1982 382sl automatic transmission shifting isues

[JustJim]

My 1982 380sl automatic transmission slips when shifting from 2-3 or 3-4. If I let off the gas as soon as it starts slipping, it shifts fine. Also, when it warms up it shifts better. Anyone know how to fix this?

Thank you.

[JustJim]

Having received no suggestions, I did some checking, and apparently my problem is more of a flare than slipping. I tried Lucas automatic transmission additive, but no change. Drained the fluid and added one bottle of TransX additive to the new fluid. The condition has improved but still exists. Happens most when car is cold, once warm it shifts normally. Thinking maybe I should drain out another quart of fluid and add another TransX, but not sure if this is a good idea or not. Anyone have any experience with this? I don't want to cause other problems.

Thanks.

[Stretch]

Originally Posted by JustJim

Having received no suggestions, I did some checking, and apparently my problem is more of a flare than slipping. I tried Lucas automatic transmission additive, but no change. Drained the fluid and added one bottle of TransX additive to the new fluid. The condition has improved but still exists. Happens most when car is cold, once warm it shifts normally. Thinking maybe I should drain out another quart of fluid and add another TransX, but not sure if this is a good idea or not. Anyone have any experience with this? I don't want to cause other problems.

Thanks.

In my experience "snake oil" as it was called here a few years back doesn't do much to help - those additives are seriously expensive when you compare the fluid volume with new Dexron II

But anyway.

By 1982 I assume you've got a 722.303 or a 722.312 transmission. This means you'll have vacuum control and a Bowden cable linkage to the throttle.

Check your throttle linkages and the tension of the Bowden cable.

Check for vacuum leaks running to the dashpot on the left hand side of the transmission

Also do a simple thing => check the fluid for cleanliness - it should be perfectly clean. Check the fluid level as per the maintenance manual. (Not a simple case of just pulling the dip stick!)

[JustJim]

Checked for vacuum leaks and found none. Throttle linkages seem to be fine. Not sure what the tension should be on the Bowden cable. How do I check that?
Fluid was changed after the Lucas additive didn't fix the problem, but even the fluid I disposed of looked clean and red. The car sat for some time before I bought it, and for a few months more while I was trying to get the engine to run enough to use the car. I know the valve bodies can get sticky when they sit for a long time so thought the right additive might free it up.

[Stretch]

The tension of the Bowden cable is usually included in chapter 30-300 in the FSM - once the rest of the throttle system has been set correctly (this is very important) then the tension of the Bowden cable needs to be set so there isn't any slack (but that it isn't pulling either)