ZexGX

iTrader: (28)

I've had 3 different 4L60E's in my car and they've all randomly exhibited a 3-4 clutch pack failure symptom - mis-shifting or "upshifting" instead of downshifting from a roll at moderate to full throttle. The first two transmissions died. The third one I still have in the car and is a pretty well built one, which should be able to handle the stock or less-than-stock amount of power that the engine in my car is putting out - and the issue is starting to come back.

We have ruled out the PCM tune as the issue - as the issue happened when on stock shift tables.

I'm starting to wonder if something else could be causing this, such as a bad sensor somewhere?

The TPS readings were fine, but I replaced the TPS sensor anyways. No change in the symptom.

Any other ideas?? Or am I just really unlucky and there's something wrong with this new trans as well?

ROCNDAV

iTrader: (100)

Driver

I used to go through 700R4s in my 383 IROC quite often.

I shifted that thing like a manual though, never being one to back down from a revving competitor.

I've had really good luck with my 4L60E, other than that one time that my deep pan, eibach springs and pothole combination didn't play nice together.

You can buy just a 3/4 clutch pack that uses more clutches than stock.

I've never tried it myself but that could hold up a bit better.

Do you have any tuning done, such as shift timing or pressure changes?

ZexGX

iTrader: (28)

Bump? Any other random ideas?

philsblwnz28

iTrader: (10)

I have been through 2 in a years time. I manually shift it when slowing down, passing if above 30mph, take to tack 4 times a mth. they were both a stock A4. My trans pressure is boosted in the computer and i think that what is killing my 3/4 clutch pack. It is been the 3/4 clutch pack both times. Then you will lose 2nd etc......

Gilbert@Ace Racing

Regardless of what clutches or line pressure is used or assigned the 3/4 clutches will fail first in a well built unit. However, they should last a more than a year or two in a rowdy combination that gets spanked alot.

There is much, much more to it than just installing the good parts guys. There are some builders that are better than others with these units because they specialize in them and constantly push the R&D envelope with them.

I would suggest that if the OP's tranny has been in there a short while at that power level then it's time for a new builder. If it has been in there for a few years, then it's just outlived it's usefulness and simply in need of a freshen up and the latest updates installed that will help it go even farther next time.

g

ZexGX

iTrader: (28)

The first time I experienced it was about 1.5 weeks & 300-400 miles after installation. My car is at stock LS1 power levels right now, and the builder is well-known in the area for being the "go-to" shop for 4L60Es. It may have been a random fluke. I will update this thread if it happens again.

bigmac108

There are several upgrades that need to be done to a transmission when it is rebuilt. Most often the 3/4 clutch packs' failure comes from a timing issue from the band coming off and on. The band applies in second and fourth gear. That means that going into third the band comes off and the 3/4 pack applies. If the band comes off too early then the trans very quicly goes back into 1st gear while the 3/4 pack is still applying, meaning a heafty shift and hard on the 3/4 pack. If the band stays on too late the trans goes into 4th gear for a slight second being hard on the 3/4 pack again. I tell you this to expalin a couple parts. Sonnax makes a 2-4 servo tube that helps exhaust that fluid applying the band faster. Aslo Alto and raybestos makes a nice 3/4 pack that increases the number of clutches in this pack making it stronger. In all my 4l60's i set the alto 3/4 pack up tight from (.030-.020). Also a high rev spring kit helps with this issue. Also a good shift kit is in order. If your trans guy would put those parts in it and set up that 3/4 pack tight i think this would solve your issue. (only set up the 3/4 pack tight if it is a high perform one, If it only has the stock 6 clutches then only oem specs)

ZexGX

iTrader: (28)

Thank you, I will check the tuning in the mean-time. These are the specs...

nh320

Hey there - read through your post and your 4L60E problems... you may want to compare your problems against this list of troubleshooting tips for the 4L60E. This is a very useful guide and I think it may help you out: http://www.twincharlotte.com/transmi...r-Charlotte-NC

ZexGX

iTrader: (28)

Sorry bud. Have already seen that link and it didn't help. This issue was over a year ago. The root cause was a shitty trans tune from a tuner that recently retired. I met a few other customers of his and they were also having 4L60E issues almost identical to mine. I bought HP Tuners and compared his trans tune to a stock F-body trans tune and it was all tweaked and changed. My new trans shifts fine now with a tune from Cunningham Motorsports (in SoCal).

maddoglou454

Glad you had it all resolve good luck with your new trans.

Thank You,
"Mad Dog" Lou

Mad Dog Transmissions
Phone 770-781-0949
Fax 770-781-0969

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