Transmission Question - The 1999 E300 - PeachParts Mercedes-Benz Forum

jake12tech · #1 11-12-2013, 07:04 PM

The trans shifts rough from 1st to 2nd and it smooths out. Coming to a complete stop and hitting the pedal it shifts hard from 1st to 2nd. Sometimes if I catch it, it won't do it because well I caught it in time. Any ideas?
Here's the history. Oh and she doesn't leak a drip.
1): Fluid change
2): Spacer/TCM adapter new (Recent)
3): Shift linkage bushing (Recent)

Is it possible a pressure regulator spring could be this problem? Something that simple and cheap could be the fix? I know these transmissions are not known at all for catastrophic failure like an old 722.3/4. Just would like to hear some opinions as at this point I'm confident it could be a stupid spring as I've seen it before.

jay_bob · #2 11-12-2013, 07:46 PM

What happens if you put the W/S switch in W? (makes it start in 2nd)
Or if you put the lever in 1 then shift it yourself to 2nd?

There is an adaptive learning algorithm on the TCM that tailors the shifting to your driving habits. I've seen a procedure on one of the other forums that resets this back to factory default.

I'd try these things before tearing into the transmission, you've got nothing to lose.

shertex · #3 11-12-2013, 08:10 PM

Quote:

Originally Posted by jay_bob

There is an adaptive learning algorithm on the TCM that tailors the shifting to your driving habits. I've seen a procedure on one of the other forums that resets this back to factory default.

That's interesting...I wonder how long it takes to adjust to a new driver (me).

jake12tech · #4 11-12-2013, 08:40 PM

Shertex, IIRC it's the first 40 shifts that matter when the doing the trans adaption.

TMAllison · #5 11-12-2013, 09:36 PM

Quote:

Originally Posted by shertex

That's interesting...I wonder how long it takes to adjust to a new driver (me).

My recollection was 50 miles. A reset can get rid of some previously learned bad habits.

40 shifts is like a mile or two for some of us....don't think the MB engineers would have set that bar that low.

jake12tech · #6 11-12-2013, 09:54 PM

Quote:

Originally Posted by TMAllison

My recollection was 50 miles. A reset can get rid of some previously learned bad habits.

40 shifts is like a mile or two for some of us....don't think the MB engineers would have set that bar that low.

I'm not sure. That's what I heard from someone and I have a book somewhere about all of this as my books started turning up. So I will look into that. I had to reset because when my mom had it, she drove it a bit slower than me. Plus, when I drive it on the highway I punch it.

jake12tech · #7 11-12-2013, 08:36 PM

Quote:

Originally Posted by jay_bob

What happens if you put the W/S switch in W? (makes it start in 2nd)
Or if you put the lever in 1 then shift it yourself to 2nd?

There is an adaptive learning algorithm on the TCM that tailors the shifting to your driving habits. I've seen a procedure on one of the other forums that resets this back to factory default.

I'd try these things before tearing into the transmission, you've got nothing to lose.

Hmmm, I failed to list the trans adaption I did. It doesn't seem to make a difference when I switch the W/S switch either. I thought of that instantly when it first started doing it. 1st to 2nd manual shifting I did not try YET. I'm going try and pull some codes with STAR at the dealer after hours with a friend and I'll see if I get any codes.

Zulfiqar · #8 11-12-2013, 09:00 PM

This sounds like a bad 1-2 overlap valve in the valve body - Sonnax make a replacement for it with a rubber O ring on it. It takes up the wear of the original metal to metal item in there.

My car shifts very crisp from 1-2 (no jolt - but crisp) after I installed the sonnax item. Previously it was doing it a bit like a worn out GM transmission.

jake12tech · #9 11-12-2013, 09:23 PM

Quote:

Originally Posted by Zulfiqar

This sounds like a bad 1-2 overlap valve in the valve body - Sonnax make a replacement for it with a rubber O ring on it. It takes up the wear of the original metal to metal item in there.

My car shifts very crisp from 1-2 (no jolt - but crisp) after I installed the sonnax item. Previously it was doing it a bit like a worn out GM transmission.

I'm calling suppliers tomorrow it looks like then and getting the best price and ordering the parts because I think you're right. It makes perfect sense.

kinghais · #10 12-08-2013, 01:50 AM

Any updates?

jake12tech · #11 12-08-2013, 02:01 AM

Quote:

Originally Posted by kinghais

Any updates?

It's up to 155,000 miles now and it hasn't done it once in about 600 miles. I haven't torn into it yet since I've got a new-to-me 560SEC holding up the lift for a valve job.

DAR2KMR2 · #12 12-08-2013, 02:15 AM

I'd also suggest checking the transmission mount. When the rubber in the mount tears or separates the "fast" 1 to 2nd shift and the downshift when decelerating can create a loose knocking, or slop, in the driveshaft. I had a similar problem with my 1997 E300D and replacement of the transmission mount brought back smooth shifting.

jake12tech · #13 12-08-2013, 02:25 AM

Quote:

Originally Posted by DAR2KMR2

I'd also suggest checking the transmission mount. When the rubber in the mount tears or separates the "fast" 1 to 2nd shift and the downshift when decelerating can create a loose knocking, or slop, in the driveshaft. I had a similar problem with my 1997 E300D and replacement of the transmission mount brought back smooth shifting.

Awesome. Thanks for the idea. I've got to do two motor mounts, so I'll order the trans mount too.

Can't Know · #14 12-08-2013, 02:48 AM

For that year -- and that symptom -- the spring is suspect. It's another fluid change, but only a partial, and if it hasn't been that long you can reuse the filter and gasket.

It's also sensitive to fluid level, so be sure you are using the proper tool and confirming the fluid temperature.

Good luck.