Truck is shifting out of lock-out too early. I think that's how you explain it :- It goes through the gears ok but when I hit about 40 mph it bogs down. Any help?

 

Anybody have any ideas? ???

 

Anybody ???

 

Since no one else seems to want to talk to you, I will try to answer your question.

This shifting into overdrive and then TC lockup at just above 40 MPH is normal. Mine does the same thing. If you are pulling a load you can lock out the OD and TC until you are ready. This is what many drivers do to keep from lugging the engine with a load.

You can delay these shifts by speeding up more rapidly.

Hope this helps

Dan

 

What RPM's does the tach. read when it's "bogged" down?

 

I'll check in the morning. It just doesn't seem right. It boggs down really bad.

 

It shift out of lock up(not sure if I got that right) at about 1500 rpms and drops down to 1000 to 1100 rpms. It's very irritating when I'm going up a hill unloaded > I have to practically floor it to get it to kick down to the right gear. It will do the same when I have 5,000 lbs. on the trailer.

 

I checked it again and it shifts out at about 35 to 40. I think that is way to slow for it to do that.

 

From what you have discribed it sounds normal to me. Mine usually locks around 35-40 MPH and engine RPM will drop to around uumm....1200 or so and it does take a substantial amount of throttle to break the lock (or kick down).

When I started driving mine it took a lot of getting used to after driving snappy gassers that shift so much more and easier.

Personally I like how these trucks stay in gear (locked) even under load, helps fuel mileage.

 

i agree, mine acts similar w/ lock-out...i never run in O/D unless im on the highway, much nicer around town when it locks out in 3rd gear instead of O/D..when mine is about to lock-up i will usually lighten the throttle pressure and let it lock up and gradually accelerate, i like this feature as u get more power w/ lock-up...just my .02

 

My 99 auto went to the dealer to have the transmission shifting software reflashed. It now shifts 3-400 rpm higher, around 2000-2100 rpms. Just a thought.

 

My '99 used to shift just like yours does until I got the re-flash because of an erratic TCC problem.The TCC problem went away but the tranny shifts totally different now-upshifts are at ~2000 or 2200 now instead of 1700-1800 also TC locks up later than before40-45 instead of 30-35.One side effect is I've lost fuel mileage.