stevieturbo

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 !

SLP IROC-Z

iTrader: (14)

I completely agree with you

rsmith

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.

pdxmotorhead

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..

cam

iTrader: (9)

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

SLP IROC-Z

iTrader: (14)

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.

slowpoke96z28

iTrader: (2)

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.

weedburner

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.

BALLSS

^^^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

jmm98LS1

iTrader: (28)

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.

weedburner

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

slowpoke96z28

iTrader: (2)

weedburner

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

stevieturbo

BULL ****


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 !

weedburner

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

Grant

stevieturbo

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 **** and made incorrectly. Why it's **** 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.

weedburner

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.

stevieturbo

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

cam

iTrader: (9)

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

stevieturbo

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.