93 T-100 Overdirve problem

I have a 93 toyota t-100 with overdrive, i have the usuall problem that when cold will not go into overdrive right away, but I have another problem, now when it is warmed up, like 15 miles down the freeway then i stop and take off again, it will not shift into overdrive, and it runs at 3500 rpm for 60 MPH, but then sometimes it works fine, no flashin O/D light.

How good is that transmission fluid looking? It should be reddish in color and clear. No brown/black colors! When was yer last drain/fill? Did you check yer fluid level properly (truck on a level surface, transmission at operating temp, engine running, transmission in park).

Yes it definatley is redish brownish more leaning twords a dark burgundy, doenst smell burnt, but i am sure a fluid change is necessary, and a filter, will new fluid really make a difference? or is it too late?

It wouldn't hurt to do a few drain/fills. How many miles do you have on the transmission? I don't think it's too late...just don't do a flush! If it was too late, yer transmission would be slipping like crazy. :(

Yer solenoid fer the overdrive might be sticking as I believe that it's electrically operated. You might look over yer harness while yer checking out yer transmission. Have you tried cycling yer O/D switch?

cycling my Overdrive? the transmission has about 57,000 on a rebuilt.

Cycling the switch...turn it on...then turn it off.

Rebuilt transmission? So the harness could've been tweaked when it was installed and is now just showing up. Is it still under warranty?

You could git the factory service manual and check it out to see what/where controls what. :D

yes have done that with the switch, so should i do the filter now or try just a drain and fill first.

The filter is just a coarse mesh. You could pull the pan and see but if yer shifting just fine I wouldn't worry about that. I would just do the drain/fill...drive a few miles and repeat.

my tacoma sized 83 with auto did this for some time before the od failed alltogether . i changed the od solineoid and checked the switch. no luck -would not engage od .