98CayenneT/A

Ok, I didn't quite know if in any way a firmer/ more solid apply of the 2-4 band or 3-4 clutch pack would help support the sprag assembly like when the overruns are on.

Yes I do have the 2-3 shift valve and had it in D3 when I let it fly from a stop.

I will ask this then..... due to needing to get out of the wot pull I let off the gas but at the wrong possible time, right in the middle of the 2-3 shift which is at 7000 rpms.

It didn't feel good when I did that, is it a good possibility that's what did it ?

mrvedit

I think we need to know for sure what broke before guessing why it broke.
I've done many runs right around 11.0 with a 625HP engine and 7000 RPM shifts and probably a hundred drag strip runs with a 525HP engine and never had a sprag (or other problem).
The Sonnax HD 2-3 shift valve does reduce the load on the forward sprang when running in D3.

BTW - Sorry for not participating lately; I'm just getting back to ls1tech after taking the summer off for numerous track events (road course racing) and keeping 4 cars track-ready for myself, my wife and "24 Hours of Lemons" team racing.

clinebarger

Mrvedit has a point, What can I say......I like talking transmissions, Even if it's hypothetical....I'm weird like that!

Installing a pressure gauge before pulling the unit is always a prudent thing to do.

I've done what you did a thousand times......Get after it & spot a hazard in the road, Patrol car etc etc and back out of it. Sure....I have killed my fair share of 4L60E's, But never from doing that.

You having it in D3 locks down the forward sprag assembly to the input drum, While there are only 2 Overruns.....They are "static" and should hold with adequate pressure.
I have seen a few broken Overrun Hub's.....The tabs that engage into the sprag assembly sheared off. But not really a common failure.

mrvedit

Yeah, if I were the supreme ruler of the universe, or at least of earth, I would require that everyone provide pressure gauge readings and a log from a scan tool before posting on this forum.
It would make diagnosing problem much easier, with less guessing.

Seriously, connecting a pressure gauge even on a trans about to be pulled and rebuilt can help identify areas that need the most careful attention, e.g. whether the pump may need to be re-machined or even replaced.

98CayenneT/A

Ok, sounds good, I won't be able to data log anything but I will post back when I get more/ better info.

Its all good, hope ya had fun. Had to be a blast to take a summer off for car events.

I was starting to get worried ya were not coming back due to enjoying reading your posts

Transmissions are kinda fun, I like learning this stuff and am not really bent about this hiccup. Really can't wait to see what I did to it lol.

Thanks much for the replays guys. I will post back when I get more info.

The snow is flying here so at least it happened at the end of the season.

98CayenneT/A

A tit more info before I get real info....I was bumping the limiter on every 1-2 shift the previous weekend at the track which had never been a problem all summer long and I let my car fly plenty of times through the 1-2 shift but I was not pulling 1.5x 60's on the street either.

mrvedit

With winter here, I hope you don't mind me hijaaking your thread to "document" some of my car events this summer.

24 Hours of Lemons in Colorado (team race) in a 1986 BMW - Here I am driving just after the start; there is some "action" just after 1:40:
Half way through the race the rear 1/3 of the camshaft broke off and we lost two cylinder; we continued and finished that way. I had the car transported to Michigan and installed a newer generation JY engine which was quite complex; basically rebuilt the entire car.

24 Hours of Lemons in Michigan two weeks ago - About 3" of rain came down. Here is a teammate driving with 94 (!) cars on the track:
Here I'm driving on the 2nd day during a lull in the rain; it's still very slippery and I have a little "trouble" on this lap:

BMW club track day - driving the 2006 C6 Corvette track car I built this summer:

BMW club track day - Here my wife is driving our 2017 M3; as a relative beginner she is with an instructor:
This was her 8th track day and she really got into it this year. I instructed her 5 of those days and she actually like me as an instructor. Since you might not believe that, here I am instructing much earlier in the year and her first time on this track (Grattan Raceway):

BMW club track day - driving my 2013 M3 at a tight track near Detroit (Waterford Raceway):

98CayenneT/A

Not at all, have at it man.

That's insane, I have never heard of a cam breaking and keep on rolling...... is that common in overhead cam cars to do that in events like that ?

Very rookie question here but in that video with your C6 vett I noticed going into every corner/ turn the tar turned black, Is that repaired road or tire rubber from cars hitting the corners ?


I do a little road racing at my power cruiser event but it's far from competitive like that but the road course is a blast. It's more of a cruise around the corners than on the straight away you can let her fly as fast as you want 3 cars wide. ( my car handles like **** anyways lol )

mrvedit

Even the mechanics at the BMW dealership (where I often hang out) thought it pretty crazy that the engine would run another 7 hours with a split cam.
A typical "24 Hours of Lemons" is actually about 8 hours of racing on Saturday and 7 hours of racing on Sunday; there is no driving at night. We noticed the loss of power late Saturday but had no idea why. So Saturday evening we opened the engine and noticed a broken valve rocker and the broken cam. The camaraderie is great in these events - other teams offered to help us replace the cam, replace the head or even replace the entire engine, but no one there had a spare. So we disconnected two injectors and drove it that way on Sunday. Slow, but we still finished in the top half.

Grattan Raceway has a lot of black patches, especially in the racing line. They are fine when dry but extremely slippery when wet.

I do enjoy non-serious road course racing. Lemons racing is competitive, but people are still reasonably friendly and not that serious. Still, going 3-wide through turns, especially in the rain, gets your full attention.

98CayenneT/A

Getting in the mood of another rebuild with the season coming up in a couple months and starting to refresh my rookie 4l60e knowledge and looking into parts to order.

My main focus will be addressing getting this thing to live with spinning it to 7000 rpms (that seemed to seriously **** it off lol ) so any tips would be very much appreciated....again

I do know at the very least the 3-4 clutch pack is toast and happened within 1500 miles while spinning it to 7000 rpms. ( Lasted 15,000 mi. only spinning to 6200 rpms with very limited clutch dust on pan drops )

Where I'm at so far.....

- adding a wide 2-4 band ( stock bw was used previously)

- thoughts on 2nd gear servo ? I'm currently running the stock 2-4 servo

- adding a 10 vane rotor in the pump. Currently using the stock 13 vane.

- adding this spring upgrade for the forward and 3-4 spring cages. https://www.summitracing.com/parts/trg-7-cs

- blocking the check ball in the input drum and drilling a bleed whole for fluid exhaust.

Any input would be again much appreciated to get this thing to stand a better chance at 7000 rpms.

mrvedit

I replaced the check ball in the input drum with a bleed hole in one build in which the 3/4 clutch wore out in one season. I blamed the blue frictions, but Chuck (owner) of Finish Line Transmissions strongly suggested that I go back to the check ball, saying that in his experience the check ball works fine even above 7500 RPM.
I also tried installing a spring-loaded check ball (forgot who made it), but it ended up rubbing against the reverse drum; when I complained to the manufacturer, they said a specific reverse drum had be used - heck with that.

Finish Line uses a billet 13 vane rotor in their top-of-the-line builds. I doubt the 10 vane increases volume by even 10%. Probably good reasons why GM spent the money to switch to 13 vanes.

Yes, the spring kit seems necessary for 7000 RPM operation. I have documented using half of the kit's springs and half stock springs, but Chuck and other pro builders say I'm overthinking it and using all the kit springs works just fine.

Using a stiffer spring in the pump is probably the most important upgrade; the Transgo part # 700PKH includes that spring and two hardened pump rings. So add that for sure.

You may need a new reverse drum to go with the wide band. (Get Carbon, not Kevlar)
The Sonnax billet 2nd gear servo is a good upgrade to go with the wide band, but not needed.

I strongly recommend the Sonnax input drum reinforcement kit. And completely removing the input shaft from the drum, and then re-inserting (pressing it) with Red Loc tite. Then install the reinforcement ring. IMHO, the area between the input shaft and the drum often starts to leak in older units and may be causing many of the premature 3/4 clutch failures in rebuilds that don't address this area. One builder documented that about half of his rebuild drums leak in this area and that the Loctite+reinforcement ring is the solution.

Perhaps Frank from PerformaBuilt would like to jump in here too.

98CayenneT/A

Sounds good man.

I do already have the input reinforcement sleeve and last rebuild checked the 3-4 circuit for leaks.

Also I do already have the Sonnax performance pack installed so would the # 700PKH still be needed or be considered a upgrade for the pump?

I will definitely be adding a new reverse input drum, wide carbon band.

Any 2-4 servo assembly you prefer?
Was going to go with the Sonnax super hold.

98CayenneT/A

Is this drilling the 2-3 feed hole in the separator plate?

mrvedit

The Sonnax Performance Pack included a stiffer pump spring; assuming you installed it, you are all set there.
I would suggest installing a pressure gauge, both on your current trans and after the rebuild. If low now, you should pay more attention to the pump. Afterwards, it help ensure the pressure is high when it should be.

I'm using the Sonnax 77911-03K "Super Hold 2nd Gear Servo", as are many of the pros. Someone might claim its overkill, but it sure doesn't hurt.

The 3rd gear feed hole should be drilled to at least .101 and many go as big as .125 without other mods. I know that Dana also drills the band release hole a bit bigger and every shift kit stiffens the servo spring a bit to ensure the band releases quickly when you speed up the apply of the 3/4 clutch.

98CayenneT/A

Yes the Sonnax spring is installed in the pump.

As far as line pressure goes... it really is not drivable as is so with that said would idle readings and a reverse reading suffice? WOT readings are really not a option until after the rebuild.

I'm definitely getting excited to see what happened to it. It was very sudden. I'm going with the 3-4 snap ring popped out. (Just a guess for fun) don't know how common that is.

Game ova

Just curious, but what did it do when it laid down?

98CayenneT/A

It was fine all summer and even at a road course event where I run it very hard. Was fine laying into it from a stop on the street also all summer long. It was not until a TNT at the end of the season that it started giving me problems. Made 8 passes and on all 8 passes it would hit the limiter on the 1-2 and the 2-3 shift which I found odd but I also was not pulling 1.5x 60's on the street either like I did all 8 passes. ( Don't know if the hard launches caused fluid starvation but I do have a deep pan and over fill )

But anyways after my TNT I drove it the next weekend and the first time I went WOT from a dig everything seemed fine. Little tire spin, the 1-2 shift was perfect then had to get out of it in the middle of the 2-3 and that was it. No more 3rd.

98CayenneT/A

Any of you guys use the sonnax valve body end plugs?

coryforsenate

iTrader: (1)

I used the ones that came with certain Sonnax kits I used. They worked fine, no problems.

bbond105

I have use the ones with O-rings and they worked great.