Betterov

I'm having an issue with the auto tranny in my 91 sr5 pickup. The first time I drive it in the morning it has trouble shifting from 3rd to 4th, and sometimes 2nd to 3rd. It will eventually do it, but it revs up to 3500 or so and sticks at that for longer than it normally would. This isnt a huge problem, it only happens the first drive of the day. I am just wondering if it is a sign of a big problem to come or something that might be fixed by a ATF flush.

dubbsbetty

iTrader: (2)

When was the last time you dropped the oil pan and changed the the atf/ filter in it? Flushes are usually a bad thing on anything hydraulic related; usually the valves get used to all the buildup around them in the valve body and every other little component as well. Flushing all that out will cause "looseness" around those components that became used to it's surrounding and now will react differently to operating temperatures, pressures, etc. Simply changing the atf and filter and cleaning the pan is a greater and safer security.

shimmy

I'm having the same kind of problem with mine right now too. I believe that from what I have been reading, that the transmission is designed to not shift into overdrive until the operating temperature of the vehicle is around 160 F. My Runner is taking an excessively long time to warm up to full operating temperature at the moment(15 minutes roughly), but once it does it shifts just fine. I'm thinking that perhaps my thermostat is sticky. Since the truck will eventually warm up to full temps I don't think its stuck open all the way, but it may be. So that's what I'm trying as a fix for that first. Maybe your truck is in need of a new thermostat as well. Best of luck.

ALLDATAdiy INFO

I would start by checking your ATF levels both cold and warm.

Betterov

I've had the truck for two years, its got 171,000 on it, I havent changed the ATF and I'm not sure it was done before I got it.

Shimmy, that makes some sense, I'll check that out.

Thanks