Just Bought A Nasty 89 S4
01-07-2015, 05:14 AM
#32
Rennlist Member
722.3 automatic no or slow reverse
No or slow engaging reverse is the most common problem in the four speed trannies. As mentioned before the B3 clutch friction discs are worn. Plus if reverse finally engages it will most of the time generate a grinding or rattling noise while driving backwards. This is the B3 actuator piston touching the K1 clutch housing.
The good news: the car will drive with no problem in all forward gears.
The bad news: there is a chance that the guide pin that keeps the B3 piston from turning breaks. One day there will be no reverse at all even after smoking a pack of cigarettes
. Once there is a significant delay until reverse engages, the B3 friction discs wear very rapidly. To fix the problem the rear axle has to come out and the tranny has to be removed.
Why am I writing this? My reverse gave up (not completely) in my GTS after 236000 km and is presently awaiting parts from our local MB dealer.
Once the automatic is out of the car the repair is not magic and certainly within the capabilities of a home mechanic. Most of the time all other parts inside are fine. My K1 clutch friction discs had no measurable wear (still at 2.1 mm) and brake band B1 had no visible wear and the factory imprinted numbers still visible. B3 clutch friction discs completely worn down to 0.9 mm (new 2,1 mm).
While the tranny is out I would highly recommend to replace all accessible seals and o-rings. PLUS the torque converter bearings!!!
I would not buy the parts from a cheaper internet source. There are aftermarket parts available but often the friction discs are of low quality. Go to your local MB dealer with the part numbers from PET, the will add "MA" to the front of the number and..... BINGO. Porsche did not change the numbers and MB will get OEM parts for you. All parts for my 722.3 cost about € 250. The hefty part is the labor (if you don´t DIY).
BTW I did not separate the final drive with the R&P. I changed the final drive ratio in my GTS not to long ago to a S4 R&P. All accessible seals were replaced with the gear ratio change.
Important!!! Especially if the car is old and the tranny is filthy from the outside. Clean, clean and clean!!! The automatic does NOT like dirt inside at all!!! You need a clean shop and some heavy duty tools (crane and balancer) to position the tranny.
The good news: the car will drive with no problem in all forward gears.
The bad news: there is a chance that the guide pin that keeps the B3 piston from turning breaks. One day there will be no reverse at all even after smoking a pack of cigarettes
. Once there is a significant delay until reverse engages, the B3 friction discs wear very rapidly. To fix the problem the rear axle has to come out and the tranny has to be removed.Why am I writing this? My reverse gave up (not completely) in my GTS after 236000 km and is presently awaiting parts from our local MB dealer.
Once the automatic is out of the car the repair is not magic and certainly within the capabilities of a home mechanic. Most of the time all other parts inside are fine. My K1 clutch friction discs had no measurable wear (still at 2.1 mm) and brake band B1 had no visible wear and the factory imprinted numbers still visible. B3 clutch friction discs completely worn down to 0.9 mm (new 2,1 mm).
While the tranny is out I would highly recommend to replace all accessible seals and o-rings. PLUS the torque converter bearings!!!
I would not buy the parts from a cheaper internet source. There are aftermarket parts available but often the friction discs are of low quality. Go to your local MB dealer with the part numbers from PET, the will add "MA" to the front of the number and..... BINGO. Porsche did not change the numbers and MB will get OEM parts for you. All parts for my 722.3 cost about € 250. The hefty part is the labor (if you don´t DIY).
BTW I did not separate the final drive with the R&P. I changed the final drive ratio in my GTS not to long ago to a S4 R&P. All accessible seals were replaced with the gear ratio change.
Important!!! Especially if the car is old and the tranny is filthy from the outside. Clean, clean and clean!!! The automatic does NOT like dirt inside at all!!! You need a clean shop and some heavy duty tools (crane and balancer) to position the tranny.
01-07-2015, 07:56 AM
#33
Three Wheelin'
Thread Starter
01-07-2015, 08:02 AM
#34
Three Wheelin'
Thread Starter
Got the air-con working today. It had no belt, I already knew that, but when i got under there I found a small piece of belt stuck between the compressor wheel and the air pump bracket. Clearly the belt has snapped at some point. I fiited the new belt and then when I looked from above I noticed the air pump adjuster bracket was at an angle and touching the air-con belt. Some wombat had the washer on the wrong side of the adjuster skewing the bracket at an angle. Swapped the fat washer around and hey presto, no touching and working air, in front and back!
02-06-2015, 10:41 PM
#36
Three Wheelin'
Thread Starter
Old girl is registered and running again. The plate issued for me was a standard South Australian licence plate but I scored with the number S928 BFB. My lads reckon the BFB stands for big fat burnout.
02-06-2015, 10:58 PM
#38
Three Wheelin'
I saw a whole series of plates which began w/ "VAJ xxxx" I'd probably have to return mine, if issued...