Transmission - 1st jerks, 2nd soft 3rd just right.....
 

1982 300CD Turbo

Hello Everyone,

Just got my "new" 300CD up and running after 4 years of non-op out on the street in front of the PO's house. When I got her home, there was not enough ATF to register on the dipstick and there was no vacuum going to the transmission. Just drained the ATF and replaced the filter over the weekend. Filter looked old, but the pan was pretty clean with no particles. After doing this the transmission seems to move into Reverse and Park easier and faster. At first it was taking a good 3-7 seconds to engage Reverse or Drive. Now it is withing 1-3 seconds. I also now have vacuum going to the transmission and adjusted the VCV so that it is getting about 12hg at idle and 0 at full throttle.

Anyway, I think I am close, but shifting is a little off and wondering what you guys think.

First into Second is harsh for the most part. The more throttle, the harder the "jerk"

Second into Third is the opposite than First into Second. It's very soft, similar to what it feels like in a manual transmision when you press the clutch in and the gas. Too many rpms for the speed/acceleration then it "glides" into third. This "softness" seems to improve with more throttle.

Third into Forth seems to be right on the money and smooth.

Anyway, I know there is a ton of stuff out there on transmissions I have read many and feel like I am on the right track. Wondering if the "softness" is something that can be adjusted, or if it is bad to drive it like this? Or if it is just a sign that the transmission may need to be rebuilt in the future. I appreciate and value your feedback. Thanks!

Hey congrats on the new CD, I love that body style!

There are a bunch of threads on trans tuning on here, you should check them out.

That said I am far from an expert but here is my 2 cents:

It sounds like you have a vacuum gauge in the mix so that's a positive. I would guess the shifts feel progressively better because in higher gears the motor's leverage is weakened. Example, it's harder to spin the wheels going from second to third than first to second. Not that an MB diesel is much on spinning tires. Anyway I would think that you need overall softer shifting at low throttle inputs. If you have an VCV that is adjustable then try turning the adjustment nuts in very small increments to increase vacuum and see if you get a good result. Best of luck Bill

Iam not an auto trans expert, but try this site, has good info.

http://www.peterschmid.com/

Have you gone through this thread?

http://www.peachparts.com/shopforum/diesel-discussion/158216-its-critical-how-you-set-your-transmissions-vacuum-system-your-diesel-mbz.html

Charlie