1992 300D no reverse
 

Anyone have an idea what would cause no reverse on a 92 300D?

Thanks

Fluid Level? Worn Linkage? Does Fwd Work? More info needed. Symptoms?

I talked to a guy a couple days ago that said there's a lock nut and adjuster bolt in the transmission that the vibration of the diesel engine can rattle it loose. He said he put the bolt back to where it was supposed to be and reverse worked again. That's all the detail he gave me but you might look into that.

Worst case might be a broken clutch band.

The manual I am looking at says reverse is engaged by actuating the B3 clutch and the one-way clutch in the geartrain. I would surmise that its in the B3, either the frictions are worn out or the piston is leaking badly. I am rebuilding one of these now...

Best case would be that it is malfunctioning due to varnish buildup in the valve body...
do a search on this forum for Trans-X for explanation.
It is a cheap first thing to try with no downside...
and the potential for real help...

Let me tell you about valve bodies, in case you have never taken one apart. There is no varnish- what there is is silt from friction material. Nothing is going to dissolve that without taking out something you are interested in keeping.

Shown below is a plate that resides between the two halves of a 722.3xx valve body. This plate, when cleaned, is simply that, a smooth plate with some holes. The image that you see is fine particles of basically friction material that has built up over the years. There is no way to remove this short of disassembly and cleaning.

What Trans-X can (and does) do is add lots of nasty solvents to your ATF.

The idea is to add these solvents, which soften and swell rubber (seals etc), and make them seal again so that all of the pressures and flows are as they should be again.

There are problems with making the seals soft and swollen, and is at best a temporary solution IMO.

Check out this thread:
http://www.peachparts.com/shopforum/diesel-discussion/203131-722-120-trans-losing-reverse.html

Worked for me :)

Nicko-

Please check your facts.

The reverse band adjustment works , and works well, for many 722.1xx, 4-bolt pan transmissions. These were used on all 240Ds , W116 300SDs , and non-turbo 300Ds.

There is no reverse band adjustment on a 722.3xx transmission, which is what the OP has. In fact, there is no reverse band, per se. It is a very different animal.

Rick

My fault, I get too used to replying to other w123 owners on here :o