Transmission

[97GreenGTP]

I have a 97 Grandprix with 213,000 miles. So far so good. Lately, I have made couple of observation about my transmission.

1. On cold morning, the converter doesn't seem to lock for the first few miles. So the engine runs at somewhat higher rpm. Then once car warms up, then it runs fine.

2. After driving 100 or so miles, once I get into a city or have to slow down and the transmission shifts down, then it shifts up with jerks. The transmission also whines and once the converter locks, then it behaves normally.

Are there some repairs that I have to be aware of that are coming my way?

Thanks in advance.

[CrazyHorst]

The first one is normal. That's the design. I think the original rationale (from TBI engines) was to make sure the "wet" manifold had heat and could deal with a low-flow situation without stumbling. In other words...a cold metal intake manifold is a very good condenser of gas vapors which tampers with the target air/fuel ratio. Lower rpms seem to accentuate any problems therein.

On SFI engines like these are that don't have a "wet" intake manifold, I believe the idea is to get the transmission fluid flowing and heated somewhat before subjecting it to the fairly sensitive application like the TCC. The TCC actually slips via PWM at a few single-digit rpms of difference to give a more compliant "feel" to the driveline, and I think the stone-cold fluid does not perform well in that application.