Snatchy Transmission 300TE

[dickinsond]

Having just been given a 1988 300TE auto I find the change up from 2-3 and 3-4 very lumpy. If I use small throttle openings, or lift off the throttle just before the box changes then the change is fairly smooth. Down changes dont seem too bad, but also once or twice in traffic the transmission seems to be dragging and the car does sometimes stall. Any advice would be welcome.

 

[television]

The vacuum pipes off or damaged could cause most of the problems

http://www.detali.ru/cat/oem_mb2.as...14P&VIN=*&CT=GA&cat=14P&SID=27&SGR=195&SGN=09

 

[dickinsond]

Vacuum pipes

Hi Malcolm

I've had the car on ramps today and found one vacuum pipe (4mm nylon) which joins the gearbox with a sort og rubber banjo union and then disappears under the aircleaner, is this the only pipe or are there others? Do you know if theres any way of testing the pipes, by sucking or blowing down them?

Dave Dickinson

 

[roofless]

this might help http://www.mercedesshop.com/Wikka/TransVacTune

 

[wireman]

The stalling makes me think that you have a detached pipe or split rubber coupling on the engine to transmission pipe.
This pipe is used to signal engine load to the hydraulic valves in the transmission, a lot of vacuum tells it the throttle is shut, less tells it that your foot is down and want some action involving lower gears.
If the pipe is leaking you have permanent demand for action and it will be a shade rough on gear change.
Also the leak will allow air into the engine which will weaken the fuel mixture and lead to poor small throttle running.
The 4mm pipe runs from the engine side of the throttle body to the transmission.

If a vac test gauge is available tee it into the pipe and see if there is a half decent vacuum there under various driving conditions, plenty on overrun/engine braking and next to none with full clog on the throttle are to be expected.

My guess is that the rubber coupling bits are tired and leaky or just fallen off the fittings and so not doing anything. Check the 4mm tube is also undamaged.

If you suck on the transmission (lift the engine end) it should hold a vacuum, your tongue should stick to the pipe end for some time.