I'm wondering if this is normal or not. I installed my tranny in July and its been real nice so far. But I never really see 4th gear much. When its cold outside it'll stay in 4th until the fluid warms up, but then it'll shift from 3rd into 4th for maybe a second then straight to lockup. It doesnt seem to be load specific either, if I romp on it hard I still have a really short 4th gear. Example, I'll stomp it, it'll shift from 3rd into 4th at about 45-50mph just for a second then go into lockup. Also sometimes it feels I have to lift up off the gas pedal for it to get out of 3rd gear so it can shift.

Anyone else have this sort of problem? Any replies are greatly appreciated. Thank you.

 

Its normal. When its cold, the ECM will not lock up the Torque converter. Once its warm enough to engage it, the ECM will lock it up between 38-45 MPH, which, under light load, is right after 4th gear engages. Even under heavy throttle, you have to be above 80% (Power enrichment Mode) to keep the ECM from locking the converter up. If you don't like how the ECM does TCC operation, you can always install your own toggle switch, or do some EPROM burning.

 

Ahh thanks fo the reply 4L60Bliss, that pretty much confirms that I'm good to go. I always look forward to your replies as you seem to know alot about trannies. Thanks again, appreciate it.

 

I had the exact same prob but its because my speedo gears in the trans are wrong since my rearend gear change to 3.73s.