Currently I have a 1994 LT1 Z28 with a solid roller 383, GTP Stage IV heads, custom grind Cam motion .606 lift cam with a 108.9 lsa . . . yada yada. The transmission is a 4L60E that was rebuilt about 1200 miles before I changed combo's. Prior to the new motor the tranny/convertor seemed to perform flawlessly. I don't remember all the details of the rebuild off hand, but it had the Kevlar clutches and the upgraded 3-4 clutch kit to name a few. The old combo was a bolt on LT1 with N20 that ran in the 11's @118. The tranny had a few n20 runs on it with no apparent slipping. After I blew the motor due to a lean condition I pulled it out to do this current motor. All in all, the car was down for 18 months. The heads, cam, intake was purchased off of a board member who dyno tuned his M6 car to 453rwhp/416TQ on a 383. He was also kind enough to give me a copy of this tune for my car. I know that the motor should be making close to the same power at the flywheel.

When I put everything back together I started to experience problems with the trans/convertor. Under normal driving conditions the trans shifts perfect, it's firm and no apparent slippage. If I stab the gas hard off the line it will break the tires loose . . . and it will spin them @25mph if the tranny is in 2nd gear and I roll on it. But if I try a 3/4 to full throttle blast, it will pull hard until @5k rpm's then slip and slide into the 7k rev limit. I have been working with Bryan at PCMforless and even with the shift points @5500, it will slam into the limiter and shift once I lay off a little. That being the case I think it is safe to assume that programming is out of the question.

I'm thinking it is the convertor . .. which by the way is a no-name junker 3000 stall. But, I don't want to get a new stall, swap it out and possibly have the same problem. Does anyone have any suggestions? I would really like to put a 4,000 stall in there, but I need it to shift? I have checked the fluid level and it is fine. This has been since the new combo which now has @700 miles on it.

Sorry for the length, but any help is greatly appreciated.

Thanks,
Pete.

 

I cooked two trannys within 500 miles of doing my stroker. Seemed like not enough fluid pressure at high rpms kept cooking the clutches. If you are unable to get enough line pressure programmed in, then you may have to do what I did with a vacuum reference pressure modulator that is independent of computer control. So far so good with that attempt.

 

would that converter be a GER? i think the problem is the line pressure at high rpm's dropping.i feel the best fix is a 13 vane front pump and to increase the line pressure alittle.

 

Thanks for the replies guys. I think that I'll scan a blast or two and record where the line pressure's are at.

Josh -- Where did you get the vacuum reference pressure modulator? I want to look into that.

Also -- Will, I got your email . . . will reply tonight.

Thanks,
Pete.

Anyone else?

 

Does this tranny have a stock pan? We have seen tranny probs down here with the pan drying out, over fill it by 2 quarts ansd see what happens. fixed most of them down here.

David

 

David -- Yes, it's a stock pan. I thought that overfilling the tranny was a bad thing . . . could be wrong though. I dont' want a short term solution to inevitably blow it up.

If I can't get it straightened out, it's being pulled and swapped with an M6.

 

I overfilled my a4 and it all blew out the vent tube and made a mess. I would not recomend doing that.

Now would say a deep trans pan help? Doesn't one off some truck fit the 4l60e and is cheap?

 

We have done it down here and it fixes lots of problems, not gonna hurt it, if it doesnt fix it drain it back out.

David

 

Do NOT over fill it by two Qts! very bad!

More then just a 13 vane pump you need to add a High RPM slide bounce spring.

There IS an issue some where. I am only putting out a mear 395RWHP and 423RWTQ AND stuffing a 100+ shot on top it with my 4L60E. I do my own programming and build my own units. this particualar unit has a few odd's and ends but short of a new set of 3-4 clutchs and a 2-4 band(installed at 50k) the damn thing is stock.

If you are worried about fluid add the stock 4x4 pan and filter. over filling the trans makes the fluid foam and putts air into the system and REALLY screws things up.

Next I would run a log with a friend on a run and see if the PCM is actually comanding the shift. go from there

BTW the above car pulls off consistant 6,800 shifts

 

Ellis -- Once the weather here dries up a bit I'll take it out and log a run or two . .. . after that, I'll come back here with the results and see what we all can come up with.

Thanks a lot,
Pete.