Trans shifting weird

[mike_dmt]

So I've been lurking around to see if anyone else has this problem: it's an '01 4.4..

A while back, I had been experiencing some RPM fluctuation at in-town cruising speeds of 35-40mph. It was relatively minor, maybe +-50 RPM. It was hardly noticeable on the tach, but I could hear it.

So, I had the trans filter and most (haven't drained and refilled again yet) of the fluid changed about 5k ago. Also had the dealer do a software update.

Now after driving it until it's warmed up, it will downshift on its own from 4th to 2nd, even if I put it in manual and try to upshift, it will stay in 2nd. It doesn't do it until it's good and warm. Maybe 30 minutes to an hour.

Unfortunately it's somewhat intermittent. Some days it's perfect, some days it's a PITA.



Any ideas?

[upallnight]

Could be the temp sensor in the trans is bad or the trans fluid getting to hot, since this only happens once the trans is warm. You will need to get the software to look at the trans fluid temp when this happens.

[mike_dmt]

I'm kind of thinking the same thing. Could it be the trans thermostat too, since it's intermittent?

I feel like if it was software, it would be fairly constant.

[mike_dmt]

I mean the TCU software.

What software do I need to pull temp readings?

[upallnight]

I think Inpa, Dis or GT1 should be able to read the trans fluid temp. If it wasn't so cold out there I would see if carsoft 6.5 and BMW Scanner 1.4 can also do this, but won't be playing around with the BM Trouble U until probably next Spring.

[mike_dmt]

Any pics of your Cuda?

[upallnight]

Sold that car long before digital camera.