When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hope it works out, did you actually find any issues?
My friends think about K1 and B3 clutchs. K1 frictions discs were used and B3 were dead. Hot spots on K1 steel plates.
These are the only used parts, maybe with oil pump. All other parts are like new.
After cleaning all parts, we change K1 steel plates and K1 and B3 friction discs. Front oil pump. All gaskets and seals.
If the failure was in the transmission, the failure will stay out right now
did you consult with Greg Brown about you valve body
I had been in contact with Greg. Very nice support
Not easy to send valve body from New Caledonia since COVID.
We have open, checked and cleaned the valve body. All ***** and springs are at the right place.
My friends think about K1 and B3 clutchs. K1 frictions discs were used and B3 were dead. Hot spots on K1 steel plates.
These are the only used parts, maybe with oil pump. All other parts are like new.
After cleaning all parts, we change K1 steel plates and K1 and B3 friction discs. Front oil pump. All gaskets and seals.
If the failure was in the transmission, the failure will stay out right now
I'm certainly hoping this fixes your problem!
I tried to post a handy chart which tells what is required from each brake band/clutch in order to make each individual "gear" function, today. However, my talents with IT stop at the power outlet in the wall, and I failed to be able to figure out how to do this. (People need to know their limitations...I certainly know mine!)
At any rate, K3 (sometimes called B3) is a dedicated reverse clutch...and if it completely fails, you are not going to move backwards. Generally, this clutch will "slip" quite a long time, before it fails completely, however your failure seems to have occurred almost instantly. This instant failure is pretty rare, unless the K3 piston blows off its retainer and thus blows out the piston seals, which you did not indicate occurring.
K1 is functional in 2nd gear, but not in the picture in 1st gear. So, if when you were having your "no reverse/no forward", if you only tried the "D" range, that could be a problem. However, if you pulled the shifter down to "2nd" gear (which should have given you 1st gear), it seems like the car should have moved forward.
All of this only means that I'm confused (which is a common issue, apparently) and still don't understand your failure mode.
As I said in the beginning, I'm sure hoping that your efforts have been successful.
One thing I'm certain you have figured out, the amount of effort to rebuild these transmissions (correctly) is extremely high. I "allow" three entire "shop days" to completely rebuild and set up one of these transmissions...and I have never accomplished this task in that amount of time!
These transmissions are, technically speaking, the most difficult item I repair, on these cars.
Thanks a lot again. Your message is very interesting.
In 8 working hours, we have only clean all parts and rebuild to K1 drum. A lot of work again before to put the transmission in the car !!!
One of the difficulties in working with the automatic transmissions is all of the different thickness clutch plates, large snap rings, shims, etc. that are required to achieve the desired clearances inside the transmission.
While the different size snap rings, shims, etc. are not terribly expensive, the quantity of the pieces that need to be "on hand" is very large.
One of the nice things about the very late autos (like your GTS has) is that most, if not all, of the Mercedes "updates" are present in these transmissions.
The real "problem child" transmissions are the '83 to '88 transmissions, which require an entire plethora of updated parts to correctly function. Very difficult to know what needs to be changed and what pieces must be changed because some other part gets changed (multiple supercessions.)
These "early" 4 speeds are very expensive (and tricky) because of these updates.
Depending on when your transmission was built, K1 and K2 drums might have "hidden" O-rings under the aluminum pieces that are riveted into the drums, which require servicing.
These O-rings get "rock hard" and leak pressurized fluid out of the piston area, causing clutch slippage.
Do you need any help in how to deal with replacing these "O-tings, or have you got this figured out?
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
K1 will have an aluminum piece, in the bottom, held in with an internal circlip. There will be a hidden O-ring under the aluminum part. You should change that O-ring.
K2 will have a riveted in aluminum part, which will need to be removed and have the O-ring replaced.
First of all my sincere best wishes for a complete recovery- taking these units apart and then getting them back together in full working order is quite something.
You have noted some worn parts but have you found a definitive fault that explains why the thing went from full working to nothing at all without any signs of degradation? Such a scenario suggests a sudden complete failure of something- apologies if I have missed something within the thread.
First of all my sincere best wishes for a complete recovery- taking these units apart and then getting them back together in full working order is quite something.
You have noted some worn parts but have you found a definitive fault that explains why the thing went from full working to nothing at all without any signs of degradation? Such a scenario suggests a sudden complete failure of something- apologies if I have missed something within the thread.
Because of the "cancel culture" and some interesting maneuvers behind the scenes to try and get me banned (yes, I'm completely aware of what you are doing), I'm very hesitant to post anything that isn't just roses and warm/fuzzy thoughts....
However, your message was the thinking that I was trying to relay to Fabien, without anything "negative" being said.
Fabien:
If I can get help with figuring out how to post this chart of pieces involved with which gears, I will try to post it.
05-16-2021, 06:28 PM
