Transmission not shifting past 2nd gear, whirring noise audible, temp gauge whacko

The transmission in my parent 2000 venture started shifting hard about a month ago now it won't shift past 2nd gear. My mother took it to a tranny shop which said it was shot and would cost $1900 to rebuild.

Anyways, ever since they got the van it felt like it was misfiring when cruising on the highway, well now that there is no third gear it no longer does this, but when it did do that the CHECK ENGINE light would come on. I think this has something to do with the tranny and has been happening since they got it. Also there is an audible whirring noise that increases with RPM's, sounds like its oming from around the middle of the engine bay, maybe a bit more to the pasenger side.

The check engine light is still on, I heard there is a throttle posistion sensor that can go bad that can cause similar troubles anyone know about this?

Also the temperature gauge goes whacko, from cold to hot very quickly and back to cold, while it goes to cold, there will be no heat coming out of the vents, but when it goes to warm heat will come out. This thing is crazy, I have less trouble with my 13 year old car that cost 2000$.

Most important is the transmission problem but any and all help is appreciated.

Thanks

the temp gauge in these are inaccurate. This is a common problem it also sounds like there could be air in the coolant system.

Now the tranny problem sounds like the torque converter. The jerking going down the road is mostlikely the TC. I would get a second opinion about the trans. I am not a transmission man, but if I had to guess it was shifting hard because the computer sensed a slip and it demanded full line pressure to limit the damage to the slipping parts. It sounds as though right now it is in "LIMP" mode. I strongly suggest getting to a different trans shop and having them get a second opinion.

Hi!

It sounds like the PCM has commanded "hot mode" e.g. due to DTC P0218 (Transmission Fluid Overtemperaure) it will freeze all shift adaptions.., lock the torque converter, full line pressure, not all gears...
In other words the PCM inhibits all functions that is expected to generate heat, slipping gears, converter fluid flow, etc.

Running in "Hot Mode" will actually cause harsh shift feel in itself due to all the measure described!, The root to the overheat may of course be in the transmission itself, but it may also be the famous intake manifold gasket, you mentioned the nervous temperaure gauge! The gasket is known problem on ventures, it is a weak part, but there is a new design available.

I suggest you to connect a scantool and read and remember the codes and then clear the codes and check engine light. Check all the fluids so you have enough coolant, engine oil and transmission fluid and no mix between them. Just drive around the block to see if the poor shiftfeel is still there.

NOTE: Don't let the engine to heat up and keep in mind that there may be other symptoms such as excessive metallic sounds, etc. that makes a test drive not a good idea!

Conclusion: Problems are many times quite entangled and sometimes different than they first seems to be, a proper diagnosis may save a lot of money avoiding not needed repairs, due to unsufficient understanding of the actual root to the cause

Good luck

/Bengt