A/T - Circumstances for Modulating Pressure Test

91mercedes02

TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: March 1991


REF. NO. 27/89


SUBJECT: ALL MODELS WITH AUTOMATIC TRANSMISSION UNNECESSARY TESTING OF THE MODULATING PRESSURE


In cases of customer complaints of "poor automatic transmission performance", the modulating pressure test should only be carried out in the following circumstances:

1. Up-shift too hard or too soft in all gears (poor shift quality while driving).

Note: On diesel vehicles the vacuum line must be in good condition, properly routed and the vacuum control valve in proper working order.

2. After R & R of the vacuum modulator.

3. After a transmission repair in which the vacuum modulator was removed and/or the clutch plates or brake bands were burned (dark in appearance) and replaced.

The modulating pressure test is not required in case of:

1. Hard engagement into "D" or "R".

2. No up-shift.

3. Deviations from individual shift points.

Future warranty claims in which the modulating pressure was checked, in any of the above cases, will be reviewed more carefully.