A/T delay when selecting gear
06-15-2010, 08:04 PM
#17
Under the Lift
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Well, I don't think it's considered functionally abnormal until it is "several" seconds. There is a one-way clutch that changes lock/unlock state between R and D. It might be sticking.
If their is a "jolt" on partial throttle shifts as well as changes between R & D, I would check the vacuum modulator and its vacuum supply.
If their is a "jolt" on partial throttle shifts as well as changes between R & D, I would check the vacuum modulator and its vacuum supply.
06-15-2010, 09:26 PM
#18
A slight delay moving from D to R and R to D is normal in my experience.
I would follow the suggestions above and give your auto box a fluid and filter chance, check the bowden cable adjustment, check that you have vacuum at the modulator valve and have your modulation pressure adjusted by a MB auto transmission expert..You can also do it yourself if you can make a adaptor piece and fit a pressure gauge, put the car up on jack stands, get the box to operation temperature, put it in D and let it run at idle speed and adjust the modulationg pressure to the value shown in the WSM to suit your car. (note: this can be done at idle instead of driving and adjusting etc.
I did this after I changed the B2 piston, checked the clearance of the B2 brake, renewed the filter, renewed the pan gasket to the updated model, filled with new fluid and my auto now works fine, but I have a slight delay between R to D, but changing from 1-2, 2-3 and 3 to D is smooth and also back down through the gears.
WYAIT also check the safety switch location as per the WSM and also the adjustment for the gear location by checking the gear change lever to coinside with the indent position on box.
Tails 1990 928 S4 Auto
I would follow the suggestions above and give your auto box a fluid and filter chance, check the bowden cable adjustment, check that you have vacuum at the modulator valve and have your modulation pressure adjusted by a MB auto transmission expert..You can also do it yourself if you can make a adaptor piece and fit a pressure gauge, put the car up on jack stands, get the box to operation temperature, put it in D and let it run at idle speed and adjust the modulationg pressure to the value shown in the WSM to suit your car. (note: this can be done at idle instead of driving and adjusting etc.
I did this after I changed the B2 piston, checked the clearance of the B2 brake, renewed the filter, renewed the pan gasket to the updated model, filled with new fluid and my auto now works fine, but I have a slight delay between R to D, but changing from 1-2, 2-3 and 3 to D is smooth and also back down through the gears.
WYAIT also check the safety switch location as per the WSM and also the adjustment for the gear location by checking the gear change lever to coinside with the indent position on box.
Tails 1990 928 S4 Auto