Whos taken the splines off the input shaft with an RXT?
 

https://cimg9.ibsrv.net/gimg/ls1tech...fd4932b7f2.jpg
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So far its ruined 2 inputs with this clutch and 3 hubs, Mcleod warrantied it the first time and said if it happened again they would stand behind it but they arent returning my calls this time. ive looked into getting a stronger input with no luck, im basically stuck going with G force internals if i want a stronger input and that is BIG money, 5Gs for gforce to build my T56. Keep in mind im NA and making 435 at the wheels. The really bad input shaft failed after the clutch was installed for 2 months. The other that isnt as bad has 3 track days on it with a total of maybe 10 passes the rest street driving.

Search, there has definitely been at least a couple of threads on the same problem in the past year or two.

And with only 435hp... any good single plate would be more than adequate. And a single would offer you a lot more spline engagement

But it does seem McLeod do have issues with their hubs, which then in turn can damage the input....NOT a good situation.

https://cimg1.ibsrv.net/gimg/ls1tech...a7d2c0be63.jpg
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Forgot to post pics of the hubs.

I know its more clutch than i need but its the best driving clutch ive had and the pedal feel is great. I also like it because it hits the tires so hard to get that perfect amount of tire spin needed to keep it from bogging.

Not much use if it fucks itself up and the input shaft ! lol

Although in the other threads, the hub splines on one disc got completely stripped, yours just look worn.

https://ls1tech.com/forums/manual-tr...-rxt-fail.html

https://ls1tech.com/forums/manual-tr...put-shaft.html

This set is just worn however my last set the outer got completely stripped just like the 2nd input shaft i posted. its been warrantied once, maybe 10 track passes and a season worth of street driving wore this one out.

When I first put an LS1 engine in my car, supercharged way back in 2003 or so. I started abusing the life out of it around 2005, and a larger better engine etc, racing as often as I could. At around 3700lbs then I got down to 10.04 at 149mph on a Textralia OZ700, just a plain single plate.

It drove extremely well, pedal not heavy and I easily had a few hundred passes on it, best 60ft only around 1.7 though.

I put maybe 12k on that driving about and to/from racing and it was faultless and when I finally did remove it, it was really only just fully broke in ! I still keep it as a spare.

At your power level etc I cannot see any good reason to be running a metallic type twin disc. Now that isnt your problem here anyway, it's clear something about McLeod's hubs are pure shite..
But just saying a good single will easily cover what you need and have almost zero risk of spline problems.

But no, 10 passes and a year of driving have not worn it out. You should be able to to do tens of thousands of miles, hundreds of passes.....and it should still not be worn out....or barely worn at all.

That said, I'm sure a Monster, ACT or indeed many other makes of clutch would work great for you either in single or twin.

I've heard nothing but good things about Textralia and diamond clutches.

FWIW a few years ago I asked Billy @ McLeod if their hubs were made USA or offshore...he said USA

I make about 30 HP less than OP with a 4200 lb car and I run a MT ET Street at the track and have hundreds of passes behind my McLeod "Street Twin" (organic disc). This clutch hits hard and I have always feared something downstream of the clutch will fail but so far nothing. I usually leave about 2500-2700 RPM. Can't say anything bad about my McLeod and have had it for 3-4 years now. I usually only got one season out of single disc clutches and the ceramic puc type sucked for chatter in city driving

Was the input shaft that was replaced a Tremec shaft or aftermarket??

Op's car must hook hard

My OZ700 was fantastic. I then bought a triple ExoSkel to replace it when I upgraded everything at the time. I did use it for a year or two and it seemed to be trouble free.

However upon pulling everything apart after an engine failure...all was not well with the clutch. The centre hubs had moved on the rivets on 2 discs, and the little rivet washer things that hold the diaphragm pivot to the cover were starting to bend.
I tried several times to get replacement parts but to no avail so gave up.

As I didnt really intend drag racing the car I bought a ACT twin organic so it would be 100% normal to drive and that clutch lasted me for several years before it finally just let go under power during a standing 1km run. TBH it had held power extremely well until that though, I was impressed.

The clutch I then replaced that with, turned into a nightmare...wish I'd just bought another ACT instead !

Theyre both tremec input shafts, no chinese stuff here.

Im hoping theyll warranty this, either way im out a lot of money, 3 input shafts to the tune of 450 each = 1350, plus the cost of the clutch if they dont warranty it. If they dont warranty Ill have to go back to the clutch i used to run which is a ram sintered iron single disc which is going to cost me another 850.

I'd like to see footage of how you drive that thing

I don't see why a simple single like this wouldnt easily do what you need and is nowhere near 850

https://www.advancedclutch.com/produ...=p3594-c201748

Or sprung to be a little more forgiving.

https://www.advancedclutch.com/produ...=p3593-c201739

Or even this certainly has plenty of torque capacity, although if you were doing lot of hard launches, the above would probably be better

https://www.advancedclutch.com/produ...=p3592-c201731

Seems to be 15% off the prices at the minute so all in the $4xx range.

Or their range of twins, which include flywheels.

https://www.advancedclutch.com/produ...sc-clutch-kits

Looks good I like the unsprung heavy duty version only problem is they only offer one flywheel that i can see and it is too light.

What do you mean they offer one flywheel ?

The single kits bolt to the original flywheel.

Or they do offer twin kits with either a lightweight flywheel ( with holes ) or full steel flywheel

And even the one with holes is by no means light by the time it's all bolted together.

https://www.advancedclutch.com/produ...olite-600585-2 this is the only flywheel i could find and its 17lbs. my car works well with a 30lb flywheel.

Oh, you're talking about their single disc flywheels.

Just use any stock flywheel or equivalent ?

What flywheel are you using with the RXT ? Dont their kits adapt some BS to bolt to a stock flywheel ?

I bought my RXT with a mcleod flywheel, suppose i could use that but it is used. Didnt have good luck the last time i had a billet steel flywheel resurfaced.

Looks like the clutch hubs are too loose of a fit onto the shaft thus allowing accelerated wear on both parts coming into contact with each other. Did you replace the shaft with an actual new LS1 input shaft or did you just replace it with another used pull out shaft?

New tremec part

Cant believe this has happened twice nevermind once. $900 in inputs so far and about to order another. Mcleod sponsors this forum and they dont have shit to say about this junk clutch, what a joke.

after this I would like to pull mine and see what it looks like if it has spline ware at all there will be hell to pay

Some one needs to rethink this hub design, looks to me the hubs don't engage the shaft with enough area to transfer all that torque so it just wears out over time. Could probably increase the hub width quite a bit and still have room to work. I can see how the single clutch design hub would have a huge advantage as far as wear. Looks like the hubs are hard enough to wear the input shaft like that. Maybe not enough dampening on the discs.

Lots of clutches are made the same way....but dont have the same problem.

The problem is clearly McLeod.

But yes a multiplate of a better design would be good.

they're common in the JDM world, but strangely a rarity for much else. This design is superior in every way and in reality not even expensive ether. I've bought centre hubs for these, and even in rip of UK they're only around £110, so overall the cost to make a clutch like this should not be stupidly expensive.

Attachment 716726

Perhaps McLeod could lengthen the hubs on the disks to use more of the available input shaft. Using the same center, and add beef rearwards for the rear disk and forwards for the front disk would help tremendously and there looks to be plenty of room to grow contact area with a deeper hub. The hub splines do look to be very sharp as well which probably helps with chatter, but looks to be eating up the input a little too easy.

Anyways something I been thinking about lately;Theres always gains to be had guys, I dont think our typical attitudes of love/hate is the way to assist our vendors in improving their products and engaging in public discussion.

If you aint breaking? You aint racing

Considering that fact, we all need to learn how to provide feedback with more sense and respect so its not so egg shelly and walls of silence will certainly come down.

dude... timing lol. Anyways did not see this before posting, but I too think this is the way to remedy this

More engagement would be good, and yes there is no reason why there could not be more, especially when it's only a twin plate.

But I've used ACT twin plates before, which also had thin hubs...and never had any problems like that.

But if the hub is getting it's teeth sheared off and it's wrecking input shafts....that is a serious problem and warranty should be covering all that damage ! Especially when it's not an isolated case.

But absolutely there are better designs out there

McLeod is very popular among the 5.0L Coyote crowd with the MT82 which uses a 23 spline shaft that isn't very stout to begin with. I can't think of a single issue where the disc prematurely wore into the shaft splines like this. Did you replace the disc when you replaced the shafts each time? Or did you reuse the disc with a new input shaft?

The discs and the shaft were replaced the first time. Now the discs and shaft have to be replaced again. not to mention the first time this happended the input was fairly new (i swaped an lt t56 to an ls t56) so im already out 2 inputs.

How long did it take for the new disc to chew through the new input shaft?

Once those hubs were worn, they are doing to chew through a new input shaft because of excessive wear allowing the them to rock on the shaft when on and off the throttle and at idle.

The first time it happend with in a month because i was racing the car often. The second time maybe 10 track passes and 5000 easy street miles. Yeah i def wont try running these discs with a input. Ive really lost my faith in Mcleod, which sucks because i really liked this clutch except for this fatal flaw

I would contact the better business bureau about this there ripping people off with that crap.

Its definitely crossed my mind

I think I may go for a Ram RTrack twin disc

Wtf?
i fought with this RXT in my sons car for 15 months now.
Havent put more than 20 miles on it since they sent the new clutch .Now i get to look forward to ahit like this happening? This bitch coming back out.
Anyone wanna buy a basically brand new rxt?

Just read your thread on yellowbullet, youve been threw hell dealing with that clutch huh? I started a thread on there its basically the same as this one. I even emailed mcleod with a link to this thread and they havent said a word to me about it. Looks like i have a 1200 dollar paper weight and 900 worth of input shafts as paper weights as well.

A lot of people do have success with these clutches, but no way in hell should this spline issue be happening and it absolutely should be a warranty issue, including subsequent damage !

I completely agree with you

I had same problem after getting T-56 / RXT in my LS conversion & nocked spilines off input shaft because I did not have proper engaugment in pilot bushing. The fit of pilot to pilot bushing (bearing) needs to be checked for proper engaugement without clutch. Just my 2 cents worth. Forgive me for my spelling - I need spell checker.

Bad alignment of the trans/bellhousing/engine block, + input shaft into the pilot will ruin the splines in a hurry, my builder says probably half of all trans to engine alignment is wrong especially on aftermarket bell housings,, I know he spends a fair amount of time making sure the dowels are in right and he only uses solid ones..

Hmm alignment issues will surely cause a lot of grief. Mic check your input shaft ( the worn one ) and compare to new, check snout bearing. What bell you running? I have a QuickTime that has been excellent

not an alignment issue, ive owned this car since 2011 ive ran 2 ram vds clutches in it as well as an ls6 clutch, none of them had issues. Never had issues with eating the splines until i put the RXT in and its been drag raced since i bought it.

That's insane that it keeps eating input shafts. Like in the other linked threads, I can only imagine it being a metallurgical thing if other hubs from other vendors are basically the same dimension and not experiencing the same failures. If alignment issues are ruled out, there's nothing left to point the finger at.

Too much clutch. The RXT has way more torque capacity than the other two clutches, so it has the potential to hit the input shaft with way more impact/force. Looks like you exceeded what the splines could take. I doubt you have enough power to make the RXT slip as long as you need it to, so either soften it's hit or install a clutch that better matches the power that you make. Both are solutions that can make your car quicker than it is now.

^^^some good points made here

multi disc clutches do hold more power (thus slip less if at all depending on HP and RPM clutch dump)….so everything "downstream" takes a bigger hit. The first thing downstream is input shaft although generally things like u joints, gears & axles take the hit first.

Given this has happened twice to OP....maybe adjust launch technique with his combo to reduce the hit everything downstream takes. McLeod has been around for a long time and makes a good product. Not saying the best but their clutches, including the RXT is in thousands and thousands of cars.

yeah OP has been through the ringer with this problem....My $.02 is examine launch RPM & clutch release timing...if everything holds something has to give. Ideally the tires but seems that is not happening in Op's case as the input shaft is taking the hit haedest

Interesting......my RXT is starting to do the exact same thing to my liberty faceplated t56. Had a hell of a time getting the trans out of the car because the discs were hung up on the input, and when I got it out you can see wear marks like your although mine's not as bad yet. I'm making over 850rwtq in a heavy car though.....but still shouldn't be happening. I'll snap pics of my input tonight.

The RXT is capable of hitting your input shaft with over 1000ftlbs, so don't be surprised that it can damage your splines. That holding power is what you paid for. It's not McLeod's fault when spline damage occurs, especially if you did the popular F-body "drill mod" which basically eliminates the oem buffer against instant engagement. It DOESN'T MATTER if the engine only makes 450ftlbs or 850ftlbs or whatever, it's still going to draw over 1000ftlbs when you dump it. Bottom line is- if you are going to run an RXT, you really need some some sort of buffer in place to control the hit.

The ClutchMaster's buffer is basically an adjustable version of the oem orifice restriction. The downside is that it also slows down the time it takes to re-apply power after a shift.

The Magnus buffer is also basically an adjustable version of the oem orifice restriction, except that it incorporates a bypass solenoid to eliminate the restriction on the shifts. Sounds like something good to speed up the shifts, until you realize that you are back to hitting the input shaft with over 1000ftlbs after a WOT shift.

The ClutchTamer is a selective buffer that allows instant pedal release/engagement, and only dampens excessively harsh clutch engagement on both launch and each shift. It does not slow down WOT shifts, it actually speeds up WOT shifts at the dragstrip by effectively shortening clutch pedal travel. Basically it eliminates the "deadband" part of the engagement cycle, so your foot does not have to move as far.

Grant

A clutch that is closely matched to hold the engine's power will pull down engine rpm at a slower rate. The more excess clutch capacity you have, the faster engine rpm will drop when you dump the clutch. That rpm drop indicates inertia energy exiting the rotating assy.

The rate that the clutch pulls down rotating assy rpm is what determines quantity/speed of inertia energy dumped into the input shaft, which is ultimately limited by the holding power of the clutch. More clutch holding power equals a faster pulldown rate, which in-turn means a bigger inertia energy release. The buffers mentioned in my earlier post temporarily reduce the clutch's ultimate holding power as a way to reduce that pulldown rate.

Grant

BULL SHIT


In no way whatsoever should the clutch be either damaging the input shaft or it's own hub splines even more so when most users are running far less and not even abusing the thing !

Most users don't have enough traction to reach the RXT's ultimate capacity.

Grant

And again, nonsense

Many could easily apply in excess of 1000lbft with traction at high speeds....and will do.

They may not do it in 1st gear...or maybe even 2nd. But 3rd...4th...5th over 1/4, 1/2 mile, mile, whatever.

You may be here to try and sell your clutch slipper, that's fair enough but to say that in any way a clutch stripping it's own splines and that of the inputs is in any way expected or normal because it's a strong clutch is just nonsense.

it's ripping the teeth because the clutch is shit and made incorrectly. Why it's shit is a mystery when other clutch makers dont have it happen...which again proves it is their problem, not a generic problem or power/torque related.

If the "many" actually did have enough power/traction to hit the limit of the RXT at speed, they either would not be using it or would be looking for more clutch.

Even with the OP's 435 to the wheels, with enough traction the input shaft will see the full limit of an un-buffered RXT after launches and WOT shifts.

Which would be a pathetically low amount of torque unable to do any harm, relatively speaking.

I can attest to 450ish rwhp being enough to cause mass carnage. There is not much I havent broken with that kind of power. Low profile drag radials are especially brutal on drivetrain parts with a stick

A bit of wheel spin on take off makes all the difference. Matt Walter has it figured out well. You can see how much wheel spin to aim for here

You've stripped the splines off a T56 input shaft with only 450hp ?

I've put double that and more through mine with various clutches and caused no harm whatsoever.

No input shafts or output shafts for that matter just munched gears and whatnot and mostly due to dead hooking and hard shifts without any wheel spin. Did you speak with McLeod and see if they can expand the hub size?

Are you completely ignoring stored energy?

Heres a video of a test pass

Looks good, looks like a little wheel spin too. The clutch is eating the splines off for some reason. Is the torque arm still mounted to the trans?

Are you completely ignoring that this is a clutch problem from McLeod, nothing more ?

No its a tunnel mount MWC t/a

I cant think of anything else other than too small of a hub or too sharp of a finish or something like that to the clutch splines. Unfortunately I dont know what you expect McLeod to do about it, its a race part and no race part I ever bought came with a warranty. Maybe they could help you out on a new replacement or a test model for a deeper hub or something like that. Its good you posted this though, many others use and recommend that same clutch so Im not sure if we will be seeing more of this or if your case is isolated? I'll be keeping my eyes and ears open thats for sure.

what is the game plan now?

Whilst this is true....clearly the fact it is happening to only their clutches, and more strangely only one disc, has to point to a clear manufacturing defect. That must be covered under warranty.

Show another brand of clutch this has happened on this platform ?

I can totally appreciate your angry and disappointed with this problem I would be too. Best you can do is call them and see if they will work with you on a solution. Be cool though, respectful and get your story clear and straight and pics ready etc. No one sells a part and wants problems, no one. People sell parts to pay bills and no other reason. To the people working there its a means to an end and its important to keep that in mind if your trying to get them to work out a solution you will be pleased with.

That said most race suppliers will only offer you a slight discount on a new part. I know Taner took his twin disk Mcleod to 6spd records for years, then it blew up, took off part of his toe iirc. Hope you have a blow proof bell on there. I really like my quick time for piece of mind. Good luck with it all

Let us know how it goes

It hasn't happened to me, I do not use McLeod, but big companies supplying poor product does anger me...indeed any company supplying substandard product does.

and holy feck....toes are important !!! lol

it does seem to be a minefield as to why clutches seem to be a struggle, it should be bloody simple to build a good clutch !

I love the LS7 clutch. So long as your not high RPM dumping its great. Obviously for the super high hp guys its not going to hold up but its been astoundingly tough if in my experience. Katech was doing modded LS9 OEM twin disk set ups I havent followed up to see how they worked out.

Certainly for older cars, I believe the LS9's required either a taller BH or some sort of spacer to gain clearance.

Of all the twins IMO the ACT offers the best value for money. New steel flywheel and twin plate with various flywheel/disc/cover options and most are under $1200.

IMO the McLeod with their adapter to bolt to a stock flywheel and then the clutch, for more money....just seems like a crappy option. I know they also offer their own flywheel, but at higher cost again

But the LS9 units look very nice as you'd expect from an OEM setup.

I think all Monster do for the most part is adapt OEM covers and discs so they can be run as twins. Again a good concept as you then have OEM quality on the parts.

Although is is extremely annoying more companies do not offer this style of clutch for the LS. It offers the best of both worlds. Strong input shaft spline setup, with a free to move friction disc arrangement and with relatively low inertia/weight. And production cost really wont be much more ( image is obviously carbon, but there are cerametallic disc options too )
And also easily rebuildable

http://www.brewedmotorsports.com/ass...k%20clutch.jpg

That looks sweet indeed.

It's commonplace with Jap stuff, although the above was an Aussie company AFAIK.

TBH that is exactly what I had wanted and tried to buy ( fucking nightmare story ) a year or two ago, but Carbonetic no longer exist. The other company who post lots of images of that same clutch, and even their boxes have it splashed all over them...no longer make it like that. Honestly wish I'd never bought what they did offer instead but that's another story.

So I'm back on a regular triple type setup with independent discs. A friend has the OSGiken of the above with the metallic discs on his 4cyl car, and with years of use including into 8's it has been superb.
Only rebuilt once after a slight user oops...But even the actual centre hub, which looks like an expensive piece, was only like £120 or so ! You'd probably pay that for 3 small splined hubs anyway !

Although strangely full rebuild kits for them tend to be expensive.

OSG metallic version. I think you can actually buy these for the LS, although their torque rating isnt huge. Maybe a very conservative rating though, as OSG stuff is superb quality. I've seen Aussie sellers list them for the LS

https://www.nengun.com/os-giken/r-series-clutch-kit

https://image.nengun.com/catalogue/1...t-5555a0d6.png

You are ignoring the fact that 450hp can hit the input shaft with the torque limit of a 1000+ capable clutch just as easily as your 950 or so can, as long as the traction is there.

So then could 900+ hit it with 1800+ ?

And it doesnt matter a damn, the clutch is shit if that is happening.

Same here I think its the hubs, each hub only has 3/8" of spline engagement, They warrantied it once now they havent got back to me about it. as far as a game plan im probably going to go back to the clutch i used to run, a Ram VDS sintered iron with a billet steel flywheel. I dont feel like trying anything new because i dont want issues im to the point i almost dont want to race the car anymore.

OP

No doubt you are frustrated at what is going on with "your" clutch. Many run the RXT and this is the first I have seen/heard of spline damage like yours....and then twice.

McLeod sponsors this section of forum. My $.02 is dealing directly with Billy or Lee @ McLeod would yield better results than open forum. Aside from calling, if you have not email Billy

My own experience with them regarding my twin has been very good. Since they are about a hr away from me I drove there with my clutch. They fixed it in 1 hr.Turned out it had a not exactly flat FW surface so clutch discs were wearing uneven. They replaced everything but my TOB on my Street Twin under warranty

FWIW I did ask Billy if their hubs were made in USA or offshore...he said USA

Maybe there is a manufacturing error...but on 2 different clutches...???

Clearly whatever your launch techniques is...you are dead hooking and the "give" in your case is the clutch hub & input shaft spline. IDK if your issue is from inferior parts or more to do with launch technique. What rpm do you launch at and do you "dump" the clutch or slightly slow the release?

Drag racing with a stick takes its tool on DL parts especially if running a tire. I have gone through several clutches over the years in short time periods. I make less HP than you but have a heavier car. My McLeod so far has outlived all others I have tried

My old ACT twin had around the same....no problems.

my old Exoskel triple had similar...no spline problems ( other problems though...but never splines )

My current Xtreme triple has a thin hub....no spline issues.

obviously the problem is the hubs....but all other clutch makers seem to make their survive with similar widths, even if it is a bad design compared to what is possible.

No matter the power input, a clutch can only hit the input shaft up to the point that it begins to slip. If a clutch's max capacity is 1100ftlbs, that's all the input shaft will see. If you dumped a 1100ftlb clutch behind 900ftlb of engine power, the input shaft would see 900ftlb of wot engine power + the clutch would draw another 200ftlb of inertia energy to reach it's slip point. If you dumped a 1100ftlb clutch behind 450ftlb of wot engine power, the input shaft would see 450ftlb of engine power + the clutch would draw another 650ftlb of inertia energy to reach it's slip point.

Grant

The plates on my old ACT twin felt quite loose on the input shaft. I used it for several years without issue though. My current clutches discs would feel a bit tighter.