Advice for transmission

[SANDEEP]

I had posted a few days back about the reverse problem on my 300sel 89. Steve replied that the reverse clutch is shot. My mechanic things the same with another possibility that the B3 seal could be bad.

Mechanic recommends that the complete transmission be rebuit as he will be there for an estimate of 1400$ canadian. My thought is just to replace the reverse clutch for a cost of 700-800$canadian.

Car has about 250,000 kms. Mechanic says that I am taking a risk andit is not wise to take a short cut. Car presently drives perfectly in all forward gears. Need advice for which way to go from members who have been in the situation.

Thanks

[rschleicher]

Sandeep,

I was in the same situation with my '91 420SEL - no reverse gear, but all forward gear shifting was working fine. (Started out as long delay time for reverse engagement, but eventually degraded to no engagement.)

As you have been advised, this is typically a worn-out B3 reverse clutch. My car, and also yours, I think, have 722.3 transmissions, and this is a pretty typical problem for them. (Prior 722.0 to 722.2 transmissions had an externally-adjustable B3 reverse band, instead of a clutch, so slippage in reverse could be easily adjusted.)

My car had 169,000 miles, and the mechanic advised that if I intended to keep the car a long time, it would probably be best to either do a total rebuild, or else install a "new" rebuilt transmission. I didn't intend to keep the car that much longer, though, so I opted for just the B3 clutch repair/replacement, assuming that everything else appeared to be in OK shape when the transmission was opened up. (Transmission needs to be removed and opened up to repair/replace the B3 clutch.) Mechanic said that things looked pretty good on the rest of the tranny, so we just stuck with the B3 repair, as well as routine replacement of seals as the tranny was being put back together. So far I have about 5,000 miles on the fixed transmission, and it is operating fine (in both directions!).

Cost for me was quite a bit higher than you are being quoted, reflecting the generally high prices in the San Francisco Bay Area. But, it was about the same 2:1 ration between a total rebuild and just the B3 repair. In my case, the two prices were $2,600 and $1,300 (US).

Good luck!

Bob Schleicher

[Roncallo]

Mechanic recommends that the complete transmission be rebuit as he will be there for an estimate of 1400$ canadian. My thought is just to replace the reverse clutch for a cost of 700-800$canadian.

Car has about 250,000 kms. Mechanic says that I am taking a risk andit is not wise to take a short cut. Car presently drives perfectly in all forward gears. Need advice for which way to go from members who have been in the situation.

I have never overhauled a MB transmission but I have overhauled just about every american car automatic, so maybe some of the MB guys can comment on the differences. I agree with your mechanic except I cant see the reason for doubling the price for the full rebuild. Once the trans is out and appart for the reverse clutch, replacing the rest of the seals and clutches is about a two hour job (by a slow guy). In any case $1400 Canadian is ~$1000.00 US. That sounds like a great price.

John Roncallo

[Kebowers]

It's really a great value to completely disassemble, inspect, replace all the seals, and any other worn parts while you have paid to remove and partially disassemble the tranny.

If YOU are doing the work, you might ask Why do I want to do more than absolutely necessary? If you want to keep driving the car go for it--the whole thing. Its a fair price.

[SANDEEP]

Update

Tried the transmission and filter as Bob suggested but there was no improvement in the reverse situation. There was a lot of clutch residue in the oil. Got the repair done. Reverse clutches were shot. The mechanic showed them to me. He also replaced one seal. Mechanic test drove the car before the repair and as the forward shifts were very good just did the reverse. Car was out for a bill of $700. Transmission is smooth. Time will tell if my gamble paid off.
Thanks everybody