myk

iTrader: (4)

Hey folks. This is for my '97Z but I wasn't sure if I should post here or in the LT1 section. Anyway I had the 4L60E in my bone stock '97Z supposedly rebuilt about 30K miles ago. Just the other day, I noticed that it's slipping as it's trying to go into 3rd and 4th/OD. Sometimes, it won't go into those higher gears so the motor just runs up in RPM's, leaving me with that wonderfully burnt fluid smell. I checked the fluid and I'm almost certain the level is proper-it's difficult to read. The A4 is obviously out of warranty but I'll be sorely disappointed if this thing needs a rebuild.

Are there any other periphery issues that could be affecting the shifting of the A4? A vaccum line, an adjustment, a valve, a solenoid, or something that won't cost $3K? Any input you guys have would be greatly appreciated. Thanks in advance!

mrvedit

Sorry, but this sounds like the notorious 3/4 clutch is worn out already. Who rebuilt it? Any idea what parts they installed for the 3/4 clutch?
A defective Pressure Control solenoid (EPC) is about the only easy-to-replace item that could cause such slippage. I know builder Dynamic396 often replaces it before pulling a customer's trans for rebuild. Perhaps a 5% chance that it might extend the life of your trans, but once the 3/4 clutch starts to slip, it wears out quickly.
Similarly, a boost valve like the Sonnax 4l60E-LB1 might reduce slippage and extend the life (at easy throttle) a bit, but you are probably looking at a rebuild in the very near future.

Sponsors FLT and Performabuilt sell a "Level 2" trans for under $1800 with shipping. (Not sure what sponsor RPM and Jake Performance sell; check them too.)

myk

iTrader: (4)

I was hoping you'd respond, and thanks for doing so quickly. In any case, you say notorious, so does this sort of thing happen often in these transmissions? What are the primary causes of the 3/4 clutch going out? I don't beat on my cars so I'm guessing the rebuild was just a hack job. To answer your question I had the work done in 2002 by an Aamco; I didn't know about LS1Tech back then and needed the car ASAP so I just went with them...

"MAC"

iTrader: (1)

mine has recently done that except all my gears was going out lol. Do you have any mods done? I would definitely get it to a good transmission shop and go ahead and pay for a rebuild or park it and try to find a 4L80E transmission those are better. Best of luck to ya.

myk

iTrader: (4)

Is the 4L80e just a bolt in? Any tuning required? What makes it better than the 4L60e? This would fit in my '97 correct?

My sensible side wants to just roll this car off of a cliff but I've always loved this stupid car, lol...

"MAC"

iTrader: (1)

LOL you should have to do some mods to get it to fit! However as you see in my signature i had to rebuild mine quit a bit unfortunately. As far as I know the 4L80E can with stand more power and more trq. I have heard they are rated at like 700hp but if they are built they can stand up wards of 1000+hp. Like i said thats what i have been told. Im sure -the transmission tunnel will need to be bigger and you will need a new trans bracket Summit racing can have the bracket at your door within a few days. However if you decide to rebuild your 60E then make sure its done right and tuned right! that also goes for the 80E as well if you opt to get that. There are more people on here that know more about the 80E than I do and im sure they will come on here and help you and probably correct something that i have said. Give it time and see what others say as well. Good luck.

mrvedit

Aamco is only going to do a stock rebuild. Unfortunately stock means soft shifting that won't disturb Miss Daisy. Soft shifting also means more slippage during the shift. Worse, it will only use 6 friction in the critical 3/4 clutch.
The proper rebuild will use 7 or 8 quality frictions, tighter clearance in the clutch pack, a drilled separator plate to apply it more quickly and a boost valve to increase line pressure across the board and make more maximum pressure available at WOT.
Generally with a performance rebuild, a 4L60E should last 3+ years at 500HP with regular track runs and spirited everyday DD.

Switching to a 4L80E is not trivial. There are many threads here on the subject. It can easily cost over $3000 including the $1000 converter. Yes, the PCM needs a different program and tuning. Trans cable mods, etc. Its all well documented here, but certainly not "bolt in".

myk

iTrader: (4)

The car is bone stock and I plan on leaving it that way. By your post I think it's safe to assume that the 4L60E will be good enough behind my LT1. In that case, I'll have to consider getting a unit from one of the sponsors or finding someone local to do a "proper" rebuild. What a pain in the ***...

"MAC"

iTrader: (1)

thanks for clearing it up i never did a 80E trans swap.

myk

iTrader: (4)

So what happened with your 60E that it needed rebuilding 3 times?

"MAC"

iTrader: (1)

well the first time my tranny blew at the drag strip because i made more power i was also told that the tuner tuned it wronged something about the pressure line, the second one was because it started slipping again and all my gears was going out. I also learned that it had 3 qrts too much transmission fluid in it as well. and the last one was because the out put shaft (thing that connects to the drive shaft, not sure if thats the correct name) locked up on me, so i had it hauled back to the transmission shop again to get it fixed.

"MAC"

iTrader: (1)

my transmission also started to break on my when i started to build my motor as well. When you make more power things will start to break so thats why i said just get a 80E because i didnt know if you was gonna build or not.

myk

iTrader: (4)

Ok, I know I'm just reaching here but could it be the shift solenoids?

mrvedit

I don't have enough experience to answer definitively, but based on your description and the prevalence of worn 3/4 clutches, I don't think so. As I understand it, if the 2-3 shift solenoid fails (stays closed) it doesn't feel like the trans is slipping under power, it feels like neutral with no hint of slippage or acceleration. Also, solenoids are more likely to burn out, putting the trans into limp mode (3rd gear).
However, it only costs $30 to replace both and they should be replaced during a rebuild anyway.