Sun Valley Mercedes Transmissions
After our transmission has been installed, it is critical that the vacuum system is checked and repaired to insure proper operation of our transmission. The vacuum system must function properly before anty adjustments to the transmission are made.
The Mercedes Benz Diesel uses a bleed off system to regulate trhe amount of vacuum suplied to the transmission's vacuum modulator. This variable vacuum system regulates the 722.118 series transmission shift points. If the vacuum system is incorrect, the transmissions could shifdt through the gears immediately or have a late shift condition.
The variable vacuum system for the 722.3.. and 722.4.. series transmission regulates the quality of shift - how hard or soft the transmission shifts.
The supply is taken from the Power Brake Booster line vacuum "T". With the engine running, and the transmisison full of ATF, unplug the suply and install a vacuum gague. The gague's needle should jump up to 15" - 20" of vacuum. If the needle rises slowly, your supply is restricted. Remove the gague and drill the oraface with a 1/16" drill bit. Make sure you do not drill all the way through the supply tube.
Our suggestion is to run a dedicated vacuum circuit for the transmission's modulator.
Install a rubber vacuum T onto the white or medal bleed valve. Plug in a dedicated vacuum line from the power brake booster line to the other T leg. Plug in your vacuum gague into the third T leg and test the vacuum amounts.
You should see around 10" of vacuum at idle dropping consectively according to throttle position, I.E. half throttle, half vacuum, full throttle, no vacuum.
If you are getting no regulation, you will need to replace this bleed valve.
After correct vacuum amounts are verified, you can now adjust the vacuum modulator.
The 722.118 vacuum shift transmission must be adjusted to dial in the shift points.
With the vacuum supply correctly configured for variable throttle position vacuum amounts, adjust the shift points by turning the adjustment T in (clockwise) for later shift points. Back off the adjustment for earlier shifts by turning the adjustment T counter clockwise.
The vacuum modulator for all other transmissions regulate the quality of shift.
Adjust clockwise for a firmer shift and counter clockwise for a softer shift.
The Throttle Pressure Cable regulates the shift timing. The more the cable pulls, the later the shift.
Use the adjuster to tighten the cable for a later shift or loosten the cable for an earlier shift.
