While driving the 05 D/A yesterday my wife called and said the truck would not shift into 5th. She was running between 70 and 75 mph and taching around 2500 rpm it has around 2000 miles on it. Has anyone had this happen to them? If so what was the result. Have an appointment on Monday with the dealer.

Thanks in Advance

Eric Scholten
05 Silverado D/A

Check and make sure that the OD lockout feature is not activated. If you cycle the key, it should reset.

I assume you mean the button on the end of the stick quick push for tow haul mode on and off and 3 second hold for OD cancel? Yup tried this and when she called, sheturned off the OD and it red lined up around 3500.

ok, just checkin.

Looks like a trip to the stealer is in order for code retrieval

I have seen this before..I realized I had it in "3" instead of "D"... would not shift into 5th..thought something was very wrong until I figured it out. D'oh!

My truck does it from time to time. Have no idea why, no codes. It will only do it when I have no scanner in the truck. :confuzeld

Don't think it was in 3rd but I'll check. She did try the OD cancel to see if that was it but it up shifted hard and redlined kinda scared her a bit. When reading the Owners manual I thought I remember it saying that On Star can read codes, does that ring a bell with anyone? If so is it possible that this could be one of the ones they might be able to read?

If your 'broken down', the Onstar operator can read the codes and determine if it's something Gomer at the local garage can fix or if it needs to be towed to a dealer.

DEWFPO

I assume you mean the button on the end of the stick quick push for tow haul mode on and off and 3 second hold for OD cancel? Yup tried this and when she called, sheturned off the OD and it red lined up around 3500.
If it redlined, then it must have been in 5th. Could it have been cold delay on TCC lockup?

If she was in fact running at ~75 mph at around 2500 RPM, then the truck had to have been in 5th.

John is on the money. That is the RPM mine runs when cold at that speed. I have only seen it a couple times when it didn't warm up before getting on the free way. The Allison site explains it in detail. Later! Frank

Mine used to do it once and a while. Prolly 4-5 times in over 2 years. It did it when it was warmed up towing, blastin the radio then looked down and notice the tach sittin on 3 k ....ooops. I just slow down to 55 or so speed back up and all was well????? Never a problem as long as Im payin attention.

No worries

Sounds like the normal function of the Allison transmission. There are cold weather protocols in the TCM programming, one of which keeps the TC unlocked until the operating temp of the the tranny hits 100° F. I know on mine, that makes 2200-2300 RPMs at 70 MPH, so 2500 RPMs at 75 MPH would be about right.