4l60e
09-20-2008, 06:41 PM
#1
Registered User
Thread Starter
Join Date: Apr 2006
Posts: 17
4l60e
I'm going to pull my trans soon because of a persistent problem in two areas, and wanted to know what parts I should be paying attention too during the rebuild based on my symptoms. Any input on what needs updated over and above a standard seal and friction rebuild would be helpfull also. The last thing I want to do, is tear it all apart, and not see anything wrong. I guess I should mention I am a Mereceds master tech, but have only ever had 1 gm trans apart, and am not sure of which hardparts are responsible for the issues I am having.
issue 1: I have no engine braking (possible overrunn clutches?) unless the convertor is in lockup mode.
issue 2: The trans will not shift at wot. The engine will just bounce off of the rev limiter until i lift off the throttle for a second so it can shift. The shift usually feels really soft at this point..definetly not right.
issue 3: I get a helatious vibration with the convertor locked up at about 2000 rpm, but can accelerate rappidly while it is happening to get it to go away...and as long as I keep the car moving fast enough to keep the rpm's away from the 2000 rpm mark, it will be fine. This issue comes and goes, and is really not as bad as it sounds....but it shakes the whole car when it happens.
I don't beleive any are caused by serious hardpart failures as, I have been driving the car for over two years like this (it is not my everyday driver, but I have put about 8,000 miles on it since this all started).
If the car is driven "normal" (up to 3/4 throttle), you would never know anything is wrong. Nice clean, sharp shifts (will even .bark the tires between 1-2 at about 70% throttle)...no slipping etc....) I regularly drive the car 80 miles roundtrip in traffic with no issues to work (no wot operation obviously).
I might just put it up for the winter and send the trans to CPT, but thought I would feel it out first.
issue 1: I have no engine braking (possible overrunn clutches?) unless the convertor is in lockup mode.
issue 2: The trans will not shift at wot. The engine will just bounce off of the rev limiter until i lift off the throttle for a second so it can shift. The shift usually feels really soft at this point..definetly not right.
issue 3: I get a helatious vibration with the convertor locked up at about 2000 rpm, but can accelerate rappidly while it is happening to get it to go away...and as long as I keep the car moving fast enough to keep the rpm's away from the 2000 rpm mark, it will be fine. This issue comes and goes, and is really not as bad as it sounds....but it shakes the whole car when it happens.
I don't beleive any are caused by serious hardpart failures as, I have been driving the car for over two years like this (it is not my everyday driver, but I have put about 8,000 miles on it since this all started).
If the car is driven "normal" (up to 3/4 throttle), you would never know anything is wrong. Nice clean, sharp shifts (will even .bark the tires between 1-2 at about 70% throttle)...no slipping etc....) I regularly drive the car 80 miles roundtrip in traffic with no issues to work (no wot operation obviously).
I might just put it up for the winter and send the trans to CPT, but thought I would feel it out first.
09-20-2008, 07:33 PM
#2
Registered User
Join Date: Mar 2002
Location: Newark, Delaware
Posts: 3,634
No engine braking is either over-run clutches, or the over-run hub, of the input sprag. The lugs break off on occassion.
4L60E's aren't designed to shift at WOT. Put a little age on the band and / or 3-4 clutches and they really don't like it. There are several areas we concentrate on to prevent this. Increase pressure at high r's, and increase holding power and make the apply quicker.
sounds like the converter has a lock-up shudder.
Frank
CPT
4L60E's aren't designed to shift at WOT. Put a little age on the band and / or 3-4 clutches and they really don't like it. There are several areas we concentrate on to prevent this. Increase pressure at high r's, and increase holding power and make the apply quicker.
sounds like the converter has a lock-up shudder.
Frank
CPT
Thread
Thread Starter
Forum
Replies
Last Post