'81 240DL Overdrive Will Not Engage, How About 30 W oil?

[algeeba]

Good morning/afternoon.

About 6 months ago I replaced all seals (except the ones on the pressure relief valve), gaskets, and bearings on my '81 240DL overdrive. Also the seals on the solenoid valve. It barely had any reverse but it did have overdrive. Now, after replacing everything reverse works good now but I don't have overdrive. Overdrive works if it is really cold outside but once the fluid heats up it stops working.

This weekend I will remove the filter cover and check that everything looks good. Solenoid valve does work. I am using regular type "F" fluid. Should I use synthetic or will 30W oil be better? It rarely gets below 20C here in El Paso, Tx.

I would like to try a different oil, synthetic or 30W, before I have to remove the OD to possibly install the upgraded pistons and seals in the front of the OD.

Mileage is 160,000

Thanks for any recommendations.

[sseir39]

You can try the 30 weight. I had to replace pistons on mine to get it work properly, but perhaps the 30 weight will do it.