'92 525 Transmission Pops Out Of Drive (GM-4L30E)

[imnprsd]

Problem #1) Any ideas as to why my 4L30E tranny pops out of the drive gear occasionally? It seems to only do this after it reaches normal operating temperature....and I can force it to pop out if gear if I drive it hard...and play with the accelleration.

I have 160,000 miles on the tranny. I just bought it... And I just had the tranny fluid and filter changed to see if that would help solve my problems. It helped, but did not fix the problem.

The problem seems to be temperature/electrical in nature, or maybe it's just time for an overhaul??? However, there are no codes to refer to and the tranny works great in manual mode.... no slipping! So I'm hoping someone can point me in a direction of a "quicker fix."

Problem #2) It takes 2 seconds to engage in reverse. Why?

[imnprsd]

I'm still having this problem. The clutch packs/torque converter seems to be fine, so can anyone tell me if they fixed the popping out of gear by changing the the wiring harness and solenoids in the tranny? The problem seem like it's electrical.

[Rigmaster]

I'm having the same problem in my '92 525iT with ~188k on it. I have been told by a local shop that you can replace the valve body/solenoid assembly inside the tranny (this can be done by dropping the pan- I believe) and that should help. The tech who told me this also drives an E34 525i and he said he did this on his personal car and it made a world of difference. I'm now debating whether to do this, or just move forward with the 5 speed swap a bit sooner than planned..............


Bret.

[dacoyote]

Problem #1) Any ideas as to why my 4L30E tranny pops out of the drive gear occasionally? It seems to only do this after it reaches normal operating temperature....and I can force it to pop out if gear if I drive it hard...and play with the accelleration.

I have 160,000 miles on the tranny. I just bought it... And I just had the tranny fluid and filter changed to see if that would help solve my problems. It helped, but did not fix the problem.

The problem seems to be temperature/electrical in nature, or maybe it's just time for an overhaul??? However, there are no codes to refer to and the tranny works great in manual mode.... no slipping! So I'm hoping someone can point me in a direction of a "quicker fix."

Problem #2) It takes 2 seconds to engage in reverse. Why?

Ok.. the bad new is.. there is no "easy" fix for what is wrong.

Normally what you are talking is create by either....

A Bad Gasket (http://www.bimmer.info/bmw/sbcncsu/index.html)

A impending valve body rebuild... or she is low on fluid....

My suggestion would be the check the fuild... however miss treated autotranny's are one of those things that may not make it back off the lift.... (at least in the car)

-Charles

[imnprsd]

Bret,

I have been actively trying to find a tranny fix which will prevent me from overhauling my tranny, but so far no luck. The post which talks about a blown gasket problem seems to be the most likely problem. Please keep us informed if you find the fix.

My email address is imnprsd@yahoo.com

[imnprsd]

Okay… This is a bit long, but after a lot of backroom chat about my tranny problem I thought I would take you through the possibilities of what might be causing my tranny problem….with the hopes that some tranny expert can help me narrow down the most likely and most inexpensive fix.

Please keep this in mind while reading this entry... In my case, the "Transmission Programme" light use to come on when it popped out of drive, but after I did a fluid change it just pops out of gear from time-to-time and does not trip any codes. It’s as if electrically the tranny thinks it's in neutral… And it’s not my gear selector switch because I replaced it.

…Plus when it does pop out of gear, I just put the tranny in S3 momentarily and then put it back into drive and everything is fine again.

....And I have concluded that the tranny popping out of gear is definitely temperature related.

…Or maybe temperature as it relates to pressure or electrical failure. That’s the big question.

Here are my thoughts. If anyone wants to add there expert opinion I (we) would all appreciate knowing a little more about how transmissions work:

1) Bad gasket -- Possibly, but it seems like the problem would get worse over time or in the very least create problems of various types -- and in my tranny it only pops out of gear at 2500 RPM, and only when I do not accelerate (coast) and do not put any drive-load on the tranny. And it’s been doing this for a long time (years).

2) Throttle Position Sensor (TPS): ...but if this failed I would hope that there would be a code, and if the TPS was bad I doubt it would cause the tranny to pop out of gear... but I'm not sure of that. Anyone know?

3) Cracked drum.... Maybe but then you would think this would trigger a code for another part failure or perhaps clutch failure code???

4) Solenoid/wire harness..... Maybe? Perhaps most likely??? But which solenoid controls Drive gear?

(…Or perhaps I should ask if one solenoid controls both the drive gear and reverse?)

5) Maybe it's not a complete failure; i.e., maybe this problem solenoid ( or solenoids) are not allowing full pressure or the right pressure combinations to let the tranny work properly???? ….But will replacing the wiring harness alone fix this problem (50/50) ???

6) ....And maybe it always happens a 2500 RPM -- under no acceleration -- because this creates the right combination of "back pressure" and the troubled-solenoid can’t handle the back forces in fluid flow??? In other words, why does the application of pressure inside the tranny (as is the case when you accelerate) prevent the popping out of gear???

7) Worn valve body.... which means the solenoids can't do there job correctly? …. IF BE THE MOST LIKELY PROBLEM, I HOPE SOMEONE CAN TELL ME IF THERE IS AN OVERHAUL KIT FOR THIS CONDITION.

8) And last but not least, the ever popular wiring harness.

WHAT SAY YOU FORUM MEMBERS? My email address is imnprsd@yahoo.com.