I have a 73 280C that has had a cold slow to go into reverse problem for years. Once the trans. (W4B 025) warms up, all is well. I got a new reverse piston and seal from an MB parts place but need to know which side of the transmission driver or passenger) this piston is located. There are two cans (covers) about the same size on either side of the trans. and it looks like the reverse band adjustment is on the passenger side. This would lead me to believe that the "band apply" piston is on the driver's side, but I don't want to tear into without knowing for sure. I also need to know how to remove the outer can (cover), and anything else that may be pertinent to doing this job. Thanks in advance for the help.

Hello MBbuff,

This is often caused by the lock nut on the reverse band coming loose and the adjustment backing out. Check this first. Yes it is located on the passenger's side. Anyway, the adjustment should be turned in until snug then back it off 1 3/4 turns.

Replacing the pistons with the trans in the car is dificult and not usually the problem. Hopefully you will not need to go this far.

__________________
Joe Alexander
Blacklick, Ohio
1964 220SE Rally (La Carrera Panamericana someday)
1966 Unimog 404s (Swedish Army)
1969 300SEL 6.3 (sold)
1969 280SL Pagoda
1973 280SEL 4.5
1974 450SLC FIA Rally car (standard trans)
1982 300D turbo (winter driver)
1986 560SEC
1989 Unimog FLU419 (US Army)
1991 300TE (wife)
2002 SLK 32 AMG (350 hp)

I agree, the reverse band adjustment seems to cure many, many of these issues.

If you do find you need to replace the piston, maybe this will help (assume this is a 722.1xx?):

http://www.jie.com/Mercedes/4_bolt_pan.htm

Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

rs899 and ja17, thanks for the info. Actually I am told it is a W4B 025 trans., but I'll check the ID plate now that I have your info. I will check the band adjustment first. I initially didn't think it was the band, as I can rev. it when it's cold and it will fall into reverse. Then when everything is warmed up it works great. I thought maybe it was a hardened seal. Also, I recently changed the fluid, which I do religiously, and it seemed to work a little better.

Got it fixed. It was the reverse servo piston seal that was split and hardened. All works good now. Thanks for everyone's help.