3-4 Shift Flare, spring kit questions on a W124
 

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.

:eek:

Sorry that's a ton of text.

I found these part numbers for the K2 piston

1262700435
1262700535

Both were about $5, however they are listed as a 190D 2.5 part that happens to interchange to the 300D, but when you pull up the 87 300D the part doesn't show up.

The guy I deal with at the dealership said that number doesn't show up in the "normal catalog" and the normal catalog has no listing for a K2 piston for the 87 300D, just a K1 part number. But he said when he pulls up those numbers in the "other catalog" they are both described as K2 parts.

I also went ahead and ordered two K1 kits. I am going to do the K1 while I am in there, and some online are saying the K1 and K2 are the same, if not I'll have a spare on the shelf for my other cars.

There were several spring changes / updates for the 722.3 transmission as well. I'm still trying to chase down what they were whunter and dieselkraut23 have been trying as well (so I understand from the threads they've started)

Post number 28

http://www.peachparts.com/shopforum/diesel-discussion/268570-3-4-flaring-shift-2.html

My understanding is in 1987 K1 and K2 may have not been the same part number but at this point they are the same. Bio300TD successfully cured a flare with a K1 kit in the K2 piston.

I wonder if my spring broke if all of the sudden I have flare and only in 1 gear.

Wouldn't an out of adjustment modulator or bowdens cable affect all gears?

The guy I deal with at the dealer is a really good guy and is very helpful (Crown in Dublin Ohio) so when he says he's looking, I believe him and he tells me there is not much information on their end for this kind of stuff.

The K2 parts that they ordered, one of them is probably the plastic holder for the spring, the K2 stuff was 50% cheaper than the spring kits. But I'll be curious to see what shows up, there is very little K2 info out there.

I used a K1 spring in the K2 slot of my '81 300SD(722.3) and it worked fine. The dealer didn't have a part # for the K2 and I had read here that the K1 works in the K2. Maybe after a little more research you'll find someone who did the same thing on your particular car.

The 3 to 4 shift didn't start flaring until I replaced the K1 on the 2 to 3 shift.