3-4 Shift Flare, spring kit questions on a W124 - PeachParts Mercedes-Benz Forum

DieselPaul · #1 07-11-2012, 04:54 PM

I just drove my 1987 300D Turbo 100 miles and as I got off the highway the car coasted down, and probably shifted down into 3rd, when I came back into the throttle the revs shot up but 4th wasn't there. After a couple seconds the revs dropped down to where they should be in 4th at that speed.

Got to the store, let it cool for an hour while we shopped.

Got back in it, it flared really bad, but grabbed 4th eventually. Got on the highway, again it was a struggle to get into fourth but eventually, got into it.

Once in 4th it has no trouble staying there, and maintains the engine RPMs it always does when it is in 4th gear.

Around town I put the selector in 3rd to prevent it from shifting into 4th, the transmission did not act up at all, so I think I've narrowed it down to a 3-4 shifting problem. If I had a bowden cable problem or a modulator problem, wouldn't I have problems in other gears? I did the VCV on the side of the injection pump adjustment again to make sure it was right.

I did some reading online on my phone, so I can't post links to what I was reading, but it sounds like I may just be having a problem with a spring in the valve body.

If that is the case, which one is the 3-4 shift, K2 or B1?

Also, the part numbers for K2 and B1 seem elusive, there is a 10 page thread on benzworld about it, I didn't read the whole thing, maybe I missed it in there.

If I am pulling the pan down should I go ahead and replace all 3?

The transmission was rebuilt 70,000 miles ago and the converter was replaced (purchased the car from a friend and I have the receipt). The fluid is nice and clear, no dirt or crud, and the level is correct. I changed the fluid when the trans had about 30k on it. If one of the springs went that quickly I'm wondering if the trans shop didn't replace the pistons springs or used cheap ones, which is why I'm leaning towards replacing all 3. They aren't expensive, and if I'm dropping the pan and replacing all the fluid, I'm not opposed to doing more work with it apart.

I've also read about the Superior transmission shift kit, but it seems to just be springs the spring kits I see from Mercedes Benz come with plastic bits as well. Do those plastic parts not necessarily need done? I like the idea of firmer shifts, I do autocross this car. And the shifts stacking is a problem under partial throttle.

Sorry that's a ton of text.