suloh

How to tell if my transmission lockup is working? What RPM should it be at 60mph? I understand that the rpm drops a few hundred rpm on lockup. Mine does about 2000rpm at 60mph on a highway.

I used to get the common tranny shudder (running over rubber strips feeling) when the tranny comes out of lockup into 4th on a gentle acceleration at 40 mph or so. So I did a drain and refill (2 quarts) and now there is no more shudder. Just wondering if the tranny is no longer locking up. Or perhaps the flush cured the shudder problem.

CUMan

You should be able to determine whether lockup is working by watching the tachometer as you accelerate. The RPM's would drop three times as the transmission shifted through the gears and then a fourth time as lockup engaged.

Slow13sGA

I had a problem with my tranny not shifting into 3rd this summer. The rpm's would stick at about 3000-3500k. It was a pain esp. when I was on the highway and had to keep up with traffic, it would take forever to get up to traffic speeds but I haven't had a problem with it since. Any suggestions what this could be a cause of it? Maybe a tranny flush would help? It had a drain and fill at 120k and I'm at 191k. This sound about right?

GRAND_LS 4

iTrader: (2)

Did you drain and refill all trans fluid, or just 2 qts over the past 70K???

If its only been the 2qts, then you REALLY need to change the fluid as soon as possible.

Slow13sGA

I talked to a service rep at the dealer. She didn't mention the amount that was used, only said it was drained and filled. What's the typical amount the dealer use with a drain and refill?? And would this be the cause of my rpm's sticking and not shifting into 3rd?