* No-Reverse Solution For GM Transmission *

very nice thread neil. im gonna have to say you are definitely the transmission guru. But yeah i remember when i have to replace the mextronix ring on an e90 transmission and seeing all that kind stuff up in there, but yeah, glad i understand how it works now. You get a lot of respect from me now. Not that that means anything.

Originally Posted by photogenic

very nice thread neil. im gonna have to say you are definitely the transmission guru. But yeah i remember when i have to replace the mextronix ring on an e90 transmission and seeing all that kind stuff up in there, but yeah, glad i understand how it works now. You get a lot of respect from me now. Not that that means anything.

thank you! but did you mean to post this in this thread or the auto tear down thread? haha

sh1t. auto tear down thread. whoops.

EDIT: wait no. its supposed to be there. LOL. yeah i just took what i learned from the other thread. before i posted.

Oh haha, no worries. I feel really good inside when people say this helped them in some way. I'm humbled to have contributed something worthwhile

Amazing, thanks for the post and a priceless read

I have done hundreds of ZF overhauls with no reverse and have never seen the reverse drum shred. There is a snap ring that in my opinion is too close to the edge of the drum considering the amount of pressure that is used for reverse, The edge of the drum cracks off just above the snap ring allowing the piston to push the clutches out too far which lets the piston in the reverse drum get crooked in the bore and shears off the seal which reduces the fluid pressure. The car might still have reverse when the fluid is cold because it is thick and can still apply enough pressure to the cluthes cold but not when it warms up.

Once the piston seal is torn there is reallly no way for the drum to shred because it doesn create enough pressure to work. The forward gears will still work because that drum and clutches is only used for reverse. I see a lot of people spend lots of money gettng this fixed when they don't need to. The drum with seal kit is like $400 and they are ZF parts. I vry rarely repace the clutches even with 100k thay are usually You can get them from wittransmissions.com

The hard part is finding someone to fix the trans with customer supplied parts. The actual time for removing and overhauling is like 6.5 hours

Originally Posted by ///OSS

Amazing, thanks for the post and a priceless read

Originally Posted by tech218

I have done hundreds of ZF overhauls with no reverse and have never seen the reverse drum shred. There is a snap ring that in my opinion is too close to the edge of the drum considering the amount of pressure that is used for reverse, The edge of the drum cracks off just above the snap ring allowing the piston to push the clutches out too far which lets the piston in the reverse drum get crooked in the bore and shears off the seal which reduces the fluid pressure. The car might still have reverse when the fluid is cold because it is thick and can still apply enough pressure to the cluthes cold but not when it warms up.

Once the piston seal is torn there is reallly no way for the drum to shred because it doesn create enough pressure to work. The forward gears will still work because that drum and clutches is only used for reverse. I see a lot of people spend lots of money gettng this fixed when they don't need to. The drum with seal kit is like $400 and they are ZF parts. I vry rarely repace the clutches even with 100k thay are usually You can get them from wittransmissions.com

The hard part is finding someone to fix the trans with customer supplied parts. The actual time for removing and overhauling is like 6.5 hours

Very good information, thank you

Any insight on the reverse solenoid for GM transmission which I have here?

Wow this is great info!

Thanks so much for the definitive write-up. A quick question.
Can the solenoid in the GM trans be replaced when changing the fluid? Is this a DIY opportunity?
Thanks again.

-Thank You So much for this Info, i was already freaking out... i have a GM unit and just like u said Warms up and reverse is all good.. Now to find out how much will a indy shop will charge to replace the solenoid.. anybody knows?

Originally Posted by mujjuman

Wow this is great info!

Originally Posted by Chilton

Thanks so much for the definitive write-up. A quick question.
Can the solenoid in the GM trans be replaced when changing the fluid? Is this a DIY opportunity?
Thanks again.

If you drop the pan while changing fluid yes it can be changed very easily. Completely a diy opportunity. If you want pictures of where it is located and how easy of a job it would be, click the Inside of an Automatic Transmission link in my sig

Originally Posted by leopoldoguti

-Thank You So much for this Info, i was already freaking out... i have a GM unit and just like u said Warms up and reverse is all good.. Now to find out how much will a indy shop will charge to replace the solenoid.. anybody knows?

It really shouldnt take more than an hour or two of labor. All you have to do is drop the pan and the solenoid is literally right there. Just pop the pin and pull it out carefully then replace it. Same to you, click the Inside of an Automatic Transmission link in my sig to see if it might be a diy job for you

first.

great thread

Great thread once again, Neil.

Great write up!

I wonder if this could relate to some instances with the infamous P0741 problem. I think there is a seperate selenoid that controls the torque converter. In my case the car shifts fine, no noticable slipping, etc. Which leads me to believe the torque converter is functioning correctly. Throws the code with a bump when 5th gear is underpressure (such as hills on the highway). To me it seems as if something is not properly engaging and locking up the torque converter.

This too would be a great money saver if possible bc through all my research everyone takes it to places that just replace the torque converter for lots of $$$

Thanks for the insight!

So, please help me understand this better.

We have an October 1999 early production 2000 323i with the steptronic transmission. I don't know if it is ZF or GM, but the window sticker says the transmission is from France. Is that enough to determine what I have and which transmission problem I may face?

I also have a 2001 325 Convertible built in April 2001. Is this car at risk?

Thanks!!

Looks like your 323i has the GM transmission and your 325 has the ZF.

.

So does that mean the 2000 323i may have the solenoid issue at some point, but the 2001 325CiC is not prone to 'reverse' issues? Only the Model Year 2000 ZFs had issues, right? And I forgot to mention that the 2001's tranny was built in Germany.

Neil, thank you so much for this info. I don't have this issue (knock on wood), but will no longer worry about it. My daughter's 2000 328i is now @135k miles, and I am now ready to face this no-reverse issue when or if the time comes, lol. Note: I replaced the atf @100k miles and will replace it again @140k miles.

Lucky GM people

First time poster here

Here's my story, I get home from thanks giving dinner at my mothers stop by Ralps to buy some groceries, get into my back put the car into reverse to back out of drive way and nothing.

I put it into drive and the car does it's usual front movement and gets into gear.

I put it back into reverse nothing again. Pull out my laptop, get on here and find this thread!

I put it in neutral push the car enough to drive into first and get out of parking lot, drive around for 5 minutes. Stop put in into reverse and :excit ed:

It works!

THANK YOU so much, I was freaking out because i just bought this car.

2000 328Ci

Now all I have to do is drop the pan, and replace that solenoid!



EDIT: Spell Check