I have had the hypertech set on 2 for the last 3000 miles. Recently, I have been noticing some possible transmission issues. During normal daily driving, I feel a hard defueling in first and fourth. Then when going into fifth, it shifts very hard and I sometimes feel something vibrate during the shift. I have 30k miles on the tranny fluid and have changed the spin on filter twice in that time. Fluid level seems fine. Is this problem programmer related or do I have another issue? Also, when I first start out in the morning, the shifting is perfect. After the tranny and truck warm up, I start getting the shifting issues. Maybe unrelated, but two weeks ago I shifted into reverse when leaving a hotel, I wouldn't move and the the shift indicator was blank. I havn't taken it to the dealership yet, and want to well informed before I do. Anyone have some ideas for me?

Only a matter of time before your engiine light comes on. I had the same problem but when it ws cold it would slam into gear. Once the tranny temp warmed to about 120-130, it started to shift smooth. It would randomly drop into 3rd from overdrive and then back into overdrive. Finally the light came on and its been at the dealership for 6 days now. All they can tell me is that there was a loss in communication between the tranny brain and the main pcm. I run a Hypertech on level 3 and never mess with it. I have 22500 miles and this is my first problem. Not Hypertech related as it would or should have fouled it up shortly after tuning it. 15,000 miles later, I do not blame Hypertech. They said it was a bad wire somewhere between the tranny and the PCM. Hopefully I'll have it back before new years. Mine also threw 9 codes, 2 tranny related. Detune it, drive it, see how she runs, then call the dealer. What I have learned about these trucks is that there will be codes thrown but not all trip the engine light, why, I dont know. Dont wait till its too late.
Nick

Hey Nick, I think you were right. I detuned it and went to the dealership. He hooked up the tech2 and found no codes in the engine or tranny. I described the problem and the service manager told me that I needed a new "rain switch". He said there is a more technical term, but that what they liked to call them. He said on the older trucks, the switch gets wet and goes bad and the transmission loses communication and has no idea what gear the computer says it's supposed to be in, so I get shift problems. He said it was $137 and the new ones don't get damaged when it gets wet. It goes on next week. Thanks for your help. This may also answer several of the other shift problem posts on the forum.

Can you say... "NSBU switch".


LATER!

Tel 9000

If it is the NSBU switch that the service manager talked about, they are under a 100k emissions warranty. You can do a search on here for nsbu and get a lot of info.
Also, if you go to an Allison dealer like I did, the switch is around $40.00. Takes about 15 minutes to install.

The newer trucks have a more reliable NSBU switch. GM switched to them at some point. I know my truck has the new one. They are much less likely to go bad. I'm curious what went wrong with yours Tel9000.

The truck goes in on Monday, but I am concerned about the SM's diagnoses. When he checked for codes, there were none. Wouldn't there be a code if I needed a new NSBU? Would that also explain the 2 second vibration I get when the truck shifts into 5th? Also, when parking the truck in a parking lot, it seems the tranny does not want to disengage. Tranny keeps pushing a little, more than ever before, even when stopped with the brake pressed. What do you guys think?

The newer trucks have a more reliable NSBU switch. GM switched to them at some point. I know my truck has the new one. They are much less likely to go bad. I'm curious what went wrong with yours Tel9000.



According to his sig, he has an 01.

There's no rain switch.What he is referring to is the NSBU switch which transmits what gear the selector is in to the TCM. Not sure if this is what your problem is although.

If your getting a vibration in OD at Converter lock up and slow engagement chances are you have a damaged converter.You probably finished it off with the hypertech tuner.
"If" the converter is bad I would have the entire transmission done as debris is through out the case.Time for a upgrade IMO.

You don't mention how many miles

Thanks Mackin. I have 138k miles. Wouldn't the computer show some type of code for the converter or the NSBU?

According to his sig, he has an 01.

DoH!!!:o:

Thanks Mackin. I have 138k miles. Wouldn't the computer show some type of code for the converter or the NSBU?

Not always

So.......how much will a new torque converter set me back?

So.......how much will a new torque converter set me back?

Depends on what you want. PM Mike L.