Transmission overdrive problem
 

I'm noticing some weird problems with the auto tranny on the 99 4runner I recently bought. First thing is, when going up a hill and keeping my foot into it enough to keep it in third gear, if I turn the o/d button off, it shifts into o/d. Turn o/d back on and it shifts back into third. Seems kinda backwards. Second problem is when I'm cruising on level ground, it feels like it shifts into o/d but the rpm only drop from 2100 to 1900. Then if I switch the o/d button off and back on again, it drops to 1500rpm. It almost feels like it goes into o/d but not all the way until I either fiddle with the button or coax it by letting up on the pedal. Anyone know what this is all about?

Anyone out there have any ideas?

we need info like mileage on tranny. mods. last time it was serviced and etc./... tranny problems are hard to diagnose

Tranny has about 160000 km(100000 miles). I noticed the problem when I bought the vehicle. I tried flushing with synthetic fluid but the problem stayed the same.

I don't have a answer for the first question but here's a stab. If you sure O/D is off when it's jumping into 4th (O/D) it sounds like maybe some wires are crossed.

As for the second half, you might be just feeling the difference of the torque converter engaging/un-engaging. I know my truck feels like it shifts gears like 5 times but it's really just the torque converter. So this might not actually be a problem.

Just to clarify, in my '97 when the OD button is out, the OD is OFF (O/D light on dash illuminates). This makes 3rd the top gear. When the OD button is in, OD is available (4th gear) and the dash light extinguishes. Is this not the behavior you are experiencing?

As Joe's Toy pointed out, TC lockup will cause an additional drop in RPM. Is much more pronounced in OD on than OD off.

When you say "turn o/d button off" are you extingushing the dash light? If so, it sounds like it's working normal to me. Otherwise, like mentioned before you might have wires crossed. Your other issue is the torque converter engaging and disengaging. Mine does it cruising around 50mph in o/d, drops a few rpms to help with fuel efficiency.

When I turn o/d off(dash light comes on) and go up a hill, it will shift into o/d. I think I'll just have to take it to a shop. Thanks.