Hey guys,

I'm not a pro on anything automatic transmission related, and hoping someone here might be able to lead me in the right direction over taking it somewhere.

On the 1-2 shift going into second gear the rpm raise and then it gets into second gear. Downshifts are fine.

Just so that we are on the same page, that transmission, a 722.1xx (W4B025) although a 4-speed, starts in 2nd unless 1st is manually selected, or full throttle kickdown is applied.

Given the above, the shift that is exhibiting a flare is actually the 2-3 shift.
The most likely fault is slipping of the K1 clutch during apply. Causes can be too low a working pressure, due to either a weak or broken spring in the working pressure control valve, or in the modulator (which operates at a fixed setting). Secondary faults can be misadjustment of the control pressure linkage, and/or low governor pressure.

Ah yes 2-3 not sure what I was thinking! Always forget about that!


I've never had to mess with the trans, are any of those issues difficult to replace, or expensive?

First step is to ensure that the control pressure rod is: 1) tight on the shaft at the transmission, 2) correctly adjusted, and 3) that the bushing(s) in the rod are in good condition/not missing.

Second step is to obtain pressure readings from the trans, and compare with specifications.

Once the control pressure linkage is set, and pressures obtained, decisions can then be made as to how to proceed.

Would the K1 spring kit be a good thing to purchase as well?

https://www.ecstuning.com/b-genuine-mercedes-benz-parts/k1-accumulator-spring-kit/1262704477/?gclid=CjwKEAjwy8bABRD5osXMovTHpmQSJACfZY0FOvrPbTT6bqiV2Qy8l6CIX0h5EXfAKruF_s6YFq5tkBoCdVXw_wcB

Googling it seems this solves alot of peoples issues..... I cannot seem to find a k1 spring kit that fits my year though...

I see the k1 spring kit has helped a bunch of peoples shifting issues like mine. Does the 76-78 300d transmission use that k1 spring kit?

This says it wouldn't work for my year...

https://www.ecstuning.com/b-genuine-mercedes-benz-parts/k1-accumulator-spring-kit/1262704477/?gclid=CjwKEAjwy8bABRD5osXMovTHpmQSJACfZY0FOvrPbTT6bqiV2Qy8l6CIX0h5EXfAKruF_s6YFq5tkBoCdVXw_wcB

No, that kit is for the 722.3/.4 transmissions that were introduced in 1980/81.

Do the earlier transmissions like in my car, even use a system like that?

There is an accumulator in the 722.1, however it serves 3 hydraulic elements (B1, K1, K2) rather than just 1 (K1).

Ohh.

So chances are with my car it's probably out of adjustment, or has a nasty vacuum issue somewhere? Fun!