Starting to hate the old SDL!
 

Well, my story starts about 1 yr. ago when I bought an '86 300sdl. It's the transmission to make a long story short. I had no idea how much foolin around I'd be doing with the vacuum bull crap.. Started with changing all the hoses and orifices in Pa. where I live and took it to Miami and on the way the kickdown took a dump and replaced that. In Miami it started to not shift again, like the kickdown switch symptoms, unplugged it and made no diff. Changed the fluid and filter again and since I was heading up to Pa. for the spring I thought I would put in some Mobil 1. and adjust the bowden cable. That seemed to fix the shifting problem at the moment, not perfect mind you but good enough to get the money pit back to Pa. Bad shifting and flairing and stuck in 2nd and totally disengaging, whoop de doo, can't tell you how many times I've opened the hood. It's probably going to fall off it's hinges before I get the darn thing figured out ! Took apart the VCV and the vac. mod., (both are riveted together) didn't break anything , cleaned them out and put 'em back together. I did the VCV first and put it back on and adjusted to specs. Whatever that means... Anyway, took it for a 10 mile drive and it shifted so smooth I couldn't believe it. Went to the salvage yard and picked up a drivers side door and threw it in the trunk. As soon as I left it started acting up again and shifting like crap, stuck in 2nd gear and flairing. Took off the hose to the trans. to get back home. Then I proceeded to rebuild the vac. amplifier. Shaved the rivets off and opened the thing up. REplaced the o-rings and put it together...... no change, only for moments it shifts OK but then I have to disconnect the hose to the tranny. REadings on the mityvac to the trans mod. range from 4 to 12. It won 't stay put no matter how much I adjust the VCV. Vac pump is a constant 21. TRans mod. is holding vacuum for about 30 mins. till it drops down to 0. Do any of you guys think it's the VCV or is it a valve body problem? I did put a pint of Trans X in after I drained some atf out and it shifted great for a few days if that tells you anything. I think I hear my wife calling me for dinner,,,, you guys are probably saying,, shut the hell up already. Oh well, thats my story and I'm sticking to it. If anybody has any suggestions before I push it off a cliff I would be most thankful. - C

Sounds like you got hydraulic problems with your tranny. Either you have a problem with your governor being stuck in postion or the valve body has stuck valves.

Hows your fluid level

Fluid level is just a hair below the top line on the stick. Where is the governor? I'll ck. it out but I'm leaning more towards the valve body problem although I hate to think about that job. I did have it at a reputable transmission shop but they didn't seem to know either. I might as well have taken it to the 3 stooges and let them have a go at it. Oh well, life goes on.

How many miles on the trans? I agree it sounds like a hydraulic problem, might be time for a rebuild depending on its maintenance history and mileage.....

Well, on the odometer it is 341k. But I have no idea if the tranny was rebuilt before I bought it from a friend who got the car from an auction.

Thats pretty high miles.....most don't make it that far without a rebuild....it may very well need one...

Allrightythen, I was afraid of that. Son of a blugersvagenschnizel !

Sounds like what mine was doing, had the trans rebuilt, all the clutch plates were wore, that was at 185k miles

Yikes, to kill one of these trannys at 185k you'd have to drive like a NYC taxi driver essentially ALL the time! :D ;)

I just ordered that Superior shift correction from Makco Dist. and give that a try. I will let you all know how it goes one way or another....

valve bodies arent too hard. All you have to do is drop the pan and remove the bolts that hold the valve body. JUST REMEMBER WHERE EvERYTHING WENT.

A few companies sells rebuild kits for mercedes transmissions.

http://www.europeantransmissions.com/shop/home.php?cat=108

Thanx , when the kit arrives next week I'm gonna git-r done and report back with the results. I hope there gonna be positive...-C

Search google for other companies because I know theres a few around.

Transmission valve bodies can also get varnished up from not changing the ATF and filter often enough.

Your results may vary, but if you want to throw relatively minor amounts of money at the problem before investing in a transmission rebuild, you can change out the ATF and filter. Use Mobile 1 Synthetic ATF - it cleans very well.

I have done this on two cars already to "repair" the transmissions.

Ken300D

To tell you the truth I have changed the fluid and filter 3 times in less than a year and the last change was in April and I used Mobil 1. I did put a pint of Trans X recently and it must have loosened up something on the valve body that was stuck because it shifted as smooth as my Mazda Millenia. Then in about a week it went back to it's flairing and horrible shifting....

One car at 185K and the other went down at 210K, I thinks that's average for the 126's.....no?

200k-225k ish seems to be the magic numbers.

But some fail sooner like my old SD at 125kish, and some last much longer like my SDL.

The difference their is that the SD was strictly an around town car for its whole life. The SDL was a commuter car that was highway driven from 70k-230k miles.

The less the shift the longer they last.

My 87 300SDL is in need of a transmission rebuild too. It slips from 1st to 3rd gear and only has 198K miles. I'm the second owner, but the first was a woman!!!! :eek:

Just kidding, but apparently she had enough money for another one and let it sit for who knows how long.... bye bye interior..... say hello to rust! :mad:

I bet its not so much the number of shifts but the frequency of fluid/filter changes.....I've been doing once a year changes for 5 years and my tranny has done 45k of city driving and 20k of highway....and its shifting better now on the new Valvoline Dexron VI Synthetic that I just put in it than it ever has before....I got my 3-4 shift firm with this fluid! Its never been firm before! There's also less torque converter slip, its about 100rpm less now at highway speeds than before. Crazy stuff. Down with Mobil! (what I used to have in it)

273k on my tranny and its shifting absolutely firm and awesome...never been rebuilt