delayed trans engagement on W126
 

I think I may have mentioned it already but my 89 420SEL still has the slow engagement syndrome. Park to drive, reverse to drive and so on. I did a complete fluid and filter change and found the pan to be clean, 129K on the clock and as far as I can see it has never been touched. Fluid was a bit dark and stinky but no bits and pieces in the pan like I have seen on one of my other W126's. Doesn't slip and shifts pretty decent, maybe a bit of flare though.

Anyhow, I ran across an article that described a solution to my exact problem which I will try to post here, if I am lucky. It deals with replacing a broken pressure regulator valve spring in the valve body, a seemingly easy repair. The spring supposedly breaks and winds into itself making the tranny lose line pressure.

Have any of ya'll seen this happen??

Here it is,

http://www.transmissionspecialty.com/parts/parts/68942-01.htm

126nut
Thanks for the link to the site. This is exactly what our 300SDL is doing. Slow to engage into drive, first drive of the day.

I'll have to jack up the car and look at the spring. I'll take pictures along the way.

Dave

Dave,

Mine seems to do it all the time. It actually sounds like the converter on yours is draining down, not sure what makes that happen but I have heard of it before. I will be getting mine up on a lift here in a few days and see what becomes of this suspected broken pressure regulator spring.

I am gradually working all the gremlins out of my recently acquired 420, looks like the ABS problem is fixed, new sensors did the trick, thanks to the help of the fine members this forum!!

Chas

Has anyone?
 

Has anyone tried this yet?
Is this spring in the valve body or is it accessable from outside the tranny?

My trans shifts with a flair from second to third when cold but it's fine after it's warmed up. Hoewever, I did open her up and the 2,3 flair may have been back at full throttle. I say "may" as I backed off the gas and let it shift (time to back off at 6000 RPM). I didn't try full throttle 3,4 shift as I live in a mountainous area and speeds would be just a little insane.

If any one has done this please speak up:D

Re: Has anyone?
 

The instructions say that you have to drop the pan but you don't have to pull the valve body.

Dang! Would have been a good preventive thing to do since I just changed the fluid and filter.

Sixto
95 S420
87 300SDL

How much was the kit? Was the kit from the same web site?

I sure hate to break in my new digital camera for all you guys on this fix, cause I'm just a rookie.

If anyone performs this spring repair will you please post the results and pics. Can this repair cure a problem with the trans wanting to downshift to a lower gear after warming up?

I was able to tear into my tranny this past week and don't really know what to say. I did find a broken spring but it was not the one in the Sonnax kit, I ended up getting a new spring for it out of a 772.3 shift kit locally at my supply house. Now it appears to me, and I was told by my trans supplier, that the Sonnax kit is for a five speed automatic, 722.5 or 6, not our trannies. I ordered the Sonnax spring for grins anyhow and I couldn't find the culprit for the Sonnax replacement anywhere in the valvebody, which I ended up pulling trying to find it.

Word to the wise, valve body disassembling is best left up to a professional, many small parts that come out of them. I had a ATSG manual and a keen eye or else I would have never gotten it back together correctly.

I still have a somewhat of a slow engagement problem. I will be moving on to other areas now, a pesky intermittent engine miss!!