Heres my first post on here, I need help. Did some searching, couldn't find the same symptoms. This forum has been helpful with other stuff dealing with this benz so I decided to join.

Info: 1983 300SD turbo automatic

Car is new to me. I have been driving it for a few weeks. 1-2 shift has been a bit harsh, 2-3 shift has been "flaring" (where it revs up then grabs the gear) occasionally.

Today, it acted like it was slipping. After a long drive, when you pushed the accel pedal, the rpms would shoot up, the car would not accelerate at all. Instead, it began slowing down like it was in neutral, coasting.

Made it back home. If you drive the car really really softly, it shifts well through all the gears great. Any hard acceleration, and it lets go, acts like its in neutral. you can rev it to the moon and it will not accelerate, feels like neutral. When you come to a complete stop, it goes back into gear.

Messing around with the different shifter positions, it was possible sometimes for it to hold a gear, under full throttle, without slipping or disengaging (and yielding great acceleration).

I have replaced a lot of older vacuum connectors to decrease the chances of a vacuum leak. Fluid doesn't look new, will probably do a filter & flush. Fluid level is a tad higher than it needs to be on the dipstick.

Does anyone know what could be causing this and how I can fix it. I want to believe that its not a blown trans, because i can make it work under stress sometimes. Almost seems like a control problem, as if its purposely disengaging, like when your coasting at speed but the engine is at idle speed.

Please help

High fluid level is bad, very bad.

You'll need to do tests. Without knowing how long it's been slipping, you'll probably need a new trans soon.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

The harsh shift is lack of vacuum probably caused by leaks possibly by vacuum pump. Flaring can frequently be adjusted out with the bowden cable once the vacuum is correct. Ask Professor Google. I found ome trans manuals online also. Send me an email address & I'll get you a dropbox link if you can't find them.

Something like "adjust mercedes 722 transmission" should turn up what you need.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

A harsh up shift is not caused by lack of vacuum. The trans is designed to upshift with zero vac. The downshift needs vac.

I had an old Dodge did some of that when the transmission filter was stopped up. I'm not saying that's the problem but changing the fluid and filter would be my first step if I didn't know when the last service was performed.

Past that, there's a ton of information on this website to help narrow the problem.

__________________
84 300SD
85 380SE
83 528e
95 318ic

Strange. My recollection is that I adjusted the VCV to soften the up shifts on the 84SD. I'll look in the book later.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Check out this link. It's not the end all to end all but it's the best starting point on evaluating a prospective vacuum problem causing hard shifts of your transmission. The link within this link is a chunk of gold.

300SDL hard shift

__________________
84 300SD
85 380SE
83 528e
95 318ic

Junkman - I was intrigued with your comment about the vcv so I went back to my 2011 thread called "'81 300SD new tranny goes clunk." Learned a lot about the vav and modulator thanks in part to Kerry. You might want to skim it. Here is one post that I pasted below that might be informative - basically you click the modulator clockwise for a sharper shift and counterclockwise for a softer shift; the vav steps down the vac coming from the vac pump from 21 ihg to 15ihg (MB spec says the tranny is designed to operate at 15 inches). The modulator is for sharper or softer shifts.

Here is what I pasted:

"Kerry - I took your advice and drove around with the mityvac plugged to my tranny. Pumped the vac to 15" for stop lights and magically the downshift clunk went completely away - just as you suggested. So things are working.

JT - I finally wiggled the dome off the VAV after hearing from Steve Brotherton and dialed it from 9" up to 15" of vac. Took it for a drive and it is almost perfect. Shifting pretty well except for a flare in 3-4 but zero clunk on downshift. Unfortunately it has stopped bleeding off vac at WOT!!

So now I get absolutely no drop in vac when I apply the throttle. It was working perfectly before at 9" vac and bad downshift clunk. So what happened? All I did was adjust the vcv nut under the dome.

I am now guessing that the 3-4 flare and just a bit of 2-3 flare is due to the fact that the vac is now not bleeding off at WOT."


Now having thought about the entire problem, I am wondering if Fedx95's tranny might just have slipping clutches?

Sorry I have been absent. I ordered the trans filter, will be doing that job soon. Junkman was nice enough to send me some documentation that might help.

I would much rather convert the car to stickshift at this point but there arent any parts cars around me.

Fluid and filter change and the car is fixed. Shifts way better than it did before when it was "fine". Filter looked gummy, fluid wasn't as bad as i thought. There was a grey non metallic sludge stuck to the bottom of the pan that I cleaned. Has the consistency of half dried paint (bottom of a paint bucket).
I hope it holds for a long time.