2004 Oldsmobile Alero - Won't shift in cold

Maintenance/Repairs
1

When the temperature goes say below 60 degrees my tranny doesn’t want to shift into overdrive right away until it warms up. And the colder the weather obviously the longer the warm-up time. Is it the tranny fluid? I always hear horror stories of changing the fluid etc or running synthetic in an older car so I’ve left it be but it’s getting that time up here in the north east

2

A transmission fluid and filter change would be the first step.

1 Like
3

That’s normal.

The computer won’t allow the transmission to engage the lock up torque converter until the engine nears operating temperature.

This is done so the engine warms up faster thereby reducing emissions.

Tester

1 Like
4

I mean the transmission won’t shift until it’s warm. The motor is warm. This varies on temp but sometimes won’t shift at all when freezing outside

5

Only overdrive

6

In that case, make sure something like a stuck open thermostat isn’t causing the problem.

Tester

7

When my automatic- truck wouldn’t shift normally from N to first gear when first starting off, when the ambient temperature was cold, it was in the shop for a complete transmission rebuild within two weeks. That’s your back-up plan. Worked well for me.

The transmission has a bevy of tubes that convey very high pressure transmission fluid to the location inside the transmission where a huge amount of force is needed to effect the shift. If the fluid pressure isn’t high enough, this is the symptom. That can be caused by a faulty transmission pump, or more often seals inside the transmission’s fluid paths are leaking. The other common cause is the clutches and bands that are used to effect the shift are worn out. If the problem is the former, there’s a pretty good chance you can get it working again just by replacing the transmission fluid. If one time helps but doesn’t solve it, try replacing it again. The fresh transmission fluid will have fresh seal conditioning chemicals. If the problem is the latter, transmission fluid changes aren’t going to be very effective, the clutches and bands will have to be replaced.