91 Turbo 4eat not shifting gears until warm ?

[KraZee]

I've had this problem for a while. When driving my suby for the 1st time ( for that day ) car wont shift between 2nd - 3rd until my temp gauge is reading normal temperature - she gets to 2nd but when I increase rpms for 3rd it 'drops out' / 'slips' to nuetral then re-engages 2nd gear. Once the temp is warm I get all 4 gears + reverse as per normal. Only happens on 1st startup or when its really cold outside regardless of time of day. Is this a gearbox or some sensor problem ?

The ATF fluid has just been recently replaced, so oil level is good.

Cheers guys

[Legacy777]

The trans is designed not to shift into overdrive (4th gear) until the tranny is up to temp. It's possible something is not working properly with that......or you have an issue going on within the transmission.

If it's inside the transmission....short of tearing it apart.....it'll be hard to diagnose the problem.

[KraZee]

OK - guess I'll start looking for a replacement. Have seen reco'd boxes (of same make) here in NZ on Trademe ranging from $1000 - $1400.

Many thanks.

[Legacy777]

No problem....sorry I don't have better news.

[Bheinen74]

the sensor which keeps it from going into 4th is a bad idea, i hate it. It has been about 0-10 degrees here now for a week, with lows below that. Tonight the windchill is to be around -30F

When I get in my car in the morning, I warm it up, so by the time i back out the drive, it (temp guage)is approaching the middle. . but when i drive the block or so to get onto the interstate, the ATF is still cold. I am instantly running at speeds about 75mph with the tranny only going to 3rd gear, and that is not good on the engine. then, after a couple miles, the ATF heats up enough for that damn sensor to tell it to shift to 4th, and it drops the rpms back to acceptable. This is a bad design in my opinion. Why would a company design a car that way, i feel like i am gonna blow my motor, or overly stress it at the 4000 rpm it is turning, until going into 4th.

[Manarius]

Gets the engine to warm up faster, prevents transmission failure - I think it was a good design idea.

[Legacy777]

The trans temp sensor is a good design. You are not going to blow up your engine. In my opinion most people are way too concerned about over revving these engines. They were designed to rev to 6500 rpm....and I'm sure there's a safety margin in there.

So you run at 3500-4000 rpm for a little bit. You'll burn a little extra gas...maybe some oil. On the flip side....if you don't have your trans fluid up to temp, you can get varnish and gummy deposits in the valves, and/or the tranny not working correctly.

[Bheinen74]

so.........heat.......and........cold, can kill the 4eat.
yuck.