You say you "filled up the tranny with fluid".

Did you top it off or refill it with the old fluid or fill it with new fluid?

The reason I ask is that I once healed a slipping OD simply by changing the fluid.

On mine, OD would always engage the first time, no problem, *if* that was within 10 minutes of starting out. Then I could drive as far as I wanted in OD. But the first time I diseagaged it, after that it would not engage solidly--it would slip.

Here is what I think was going on. Trans fluid gets thinner as it heats up. Manufacturers put in additives to limit the change in viscosity from cold to hot. Old fluid loses these additives--so on my car the hot fluid was too thin and it was bypassing the old, worn seals, and the unit couldn't maintain enough pressure to stay in OD.

Worked fine for another 50k until the main output bearing failed.

For me it took a lucky guess and a talk with my dad who's a chemical engineer.

There's something else that might help. I bet there are additives to improve the condition of the rubber in those seals. Maybe ODguru or someone else who knows transmissions can suggest something to try.

Doing both of the above would be lots easier and cheaper than rebuilding your OD unit.

Good Luck. Sorry to be so longwinded

Doug Harvey

You have failing actuating piston seals. The OD must come off the tranny to accomplish the renewal.

See the 700-900 FAQ's under the Boards Features box for a how to.

Or contact me for the instructions.

Duane

Sounds like my OD. Does it work when its cold? Does it work at higher speeds? It could be a clogged filter or bum solenoid, but most likely the seals are gone inside the unit. Then the unit can't make enough pressure to shift. If this is your problem it tends to work when its cold I asssume becuase the oil is more viscous, and it works when going faster because the pump is pumping faster.
I've already ruled out electrical problems on mine and I'm going to have a go at putting new seals in it. I have seen one apart at the junkyard and it does not look too bad.