Is the mechanic right?
 

I have tranny issues. Modulator is busted or is not set to the right pressure so I have it bypassed. I'm going to have the mechanic see if he can set it today or if I need a new one. Other than that the mechanic said I need to get a used tranny valve body and that would fix my problems. Is that necessary? Is their not some other options to fix the one I have? Thanks

You modulator is "busted" and your mechanic wants to replace the valve body?

What's to say that a new modulator (which you apparently need anyway) won't fix your (unspecified) problem?

The problem is that if I connect the modulator it won't even shift into second. As it is bypassed now, it shifts through all gears but waay to quickly, especialy 2-3 and 3-4, and the shifts are incredibly soft. No drop in the rpms at all going into fourth but I do believe it engages.

Also, it doesn't want to shift down to 3rd from fourth as I slow down. Once I'm in 4th I'm stuck there until I am at an almost dead stop. What rpms should I be reading at my shift points? Adjusting the bowden does very little.

Have you also adjusted the cable? The modulator only controls the "firmness" of the shifts.

I don't believe the modulator is going to solve your issues.

If it were me, I'd find some Trans-X and run it for several hundred miles. If the valve body is suffering from varnish accumulation due to neglect, the trans-x will cure it.

I've been told that transmission additives could be deadly for the transmission. I don't like the idea of sludge and particulates getting dislodged and circulating through the transmission. Even with a new filter. Is it really safe? Is their a way to clean the valve body manually? Thanks for the suggestions.

Consider the source.

The Trans-X has proven it's mettle for others on the forum.

You don't have a cost effective alternative. There are ways of cleaning the valve body and restoring its proper function, but its not a job for the weekend mechanic.

Brian - your comment re Trans-X
 

Brian

Wanted to pick up on your comment here. I recently bought a 100K mile 380SL that had sat for a year undriven before I bought it. Most systems are operating OK but there is an annoying momentary slip on the 2/3 upshift when the tranny is cold.

I know nothing about trannys and my initial research is pointing to a sticky or sluggish valve - can't remember which one without referring to a print out at home.

Given the history of the vehicle are there any proprietary tranny degummers I should use and are safe in a Benz. We have not yet changed the tranny fluid or filter as brakes, shocks, timing chain and other priorities have come first!

Tnx, Ritchie L

Don't know much about the gassers Ritchie, but it appears that you've got a vacuum problem. A bit less vacuum to the modulator will firm the shifts and the 2-3 flare will disappear.

I wouldn't go with the Trans-X in that situation.

Thanks. It's much harder to get SL advice than it is diesel. The SD is running like a charm .... the SL is at that wonderful let's find out what else has been neglected stage....

Ah well, I'll go back to poking around the SL forum.

R

I am what I would consider a very high level DIYer. There is nothing that I have tried to fix that I have failed on.
However, valve bodies are scary. There is somewhere in the neighborhood of 50 valves, or parts of valves, 35 springs, 18 balls. Some of the valves have multiple springs and multiple valves all in one hole. To clean the valve body properly every single piece needs to come out of the it, and most importantly it all has to go back exactly as it came out.

Use some Trans-X or find a rebuilt valve body to put in it.