Allison Gear Indicator Issue

[Eric Alan]

Has anyone had a problem where the transmission shifts OK, acts completely normal when cold then after driving a bit, stopping and putting the transmission into park, the gear indicator back light stops working in P N D 2 (mostly)? After the truck sits for 10-15 minutes all is back to normal....

This started with a code thrown last week during a snow storm (as was in 4Hi) all seamed OK. The dealer said it was a "transmission shift module" and just replaced it today. smile.gif

I drove out of the lot back to work and the problem is still there (as described below)... :(

After driving for 5-10 minutes and then going to park, the transmission shifts to park (it actually does) the gear indicator goes blank. I recognized this first because the doors did not automatically unlock.

Shifting after this causes the gear indicator back light to only come on in: Reverse, 1st, 3rd. The transmission shifts normally and appears to be working fine. All gears work and 4WD seams OK.

Fluid levels are fine and trans temp is normal.

Back to the dealer tomorrow, but I am a bit confused by all this.... :confused:

BTW I have 42K on the truck and without really pressing hard the service manager wrote up the part and labor as goodwill and I paid for one hour of diagnostics. (Great deal, not certain I got what I paid for though smile.gif )

Any help or thoughts would be appreciated!!!

[heartbeatcanada]

NSBU switch. I'll bet the farm on it's the neutral safety backup switch. If its still under warranty let them fix it, if its not don't buy the switch from GM, buy it from an Allison dealer as the gm dealer charges double of what you can get it at the Allison dealer. New replacement should be tan in color. Later Jeremy smile.gif

[More Power]

There's a new article in the Member's Area that discusses this very problem.

http://www.thedieselpage.com/members/features/nsbu.htm

MP

[HD-Nate]

Originally posted by heartbeatcanada:
NSBU switch. I'll bet the farm on it's the neutral safety backup switch. If its still under warranty let them fix it, if its not don't buy the switch from GM, buy it from an Allison dealer as the gm dealer charges double of what you can get it at the Allison dealer. New replacement should be tan in color. Later Jeremy smile.gif What he said :yesnod:

[Eric Alan]

Thanks Everyone! All is fixed as predicted with the NSBU switch. The dealer covered it with no issue.

As an engineer in product development and R&D this kind of product issue happens all the time. The difference between good companies, with good reputations, and those without are how they handle these issues. The car industry, as a whole, does not rank high in terms of this. :rolleyes:

I wonder what would happen if just one of them started corporately handled this issues up front???? :rolleyes:

[Maxter]

The new (tan) NSBU switchs don't seems to be alot better than the black ones. My original one died in december 2002 @ 45,000km and my new one died in december 2003 @ 89,000 km.

My waranty was over but I managed to get the switch free and paid only the labour.

It "look" like a recuring problem and the next one will be at my charge.

I guess the Canadian winters and regular plowing are part of the problem but still, GM should come up with a definitive fix for that problem.

Good luck with your new one!

JF.

[dmaxalliTech]

Maxter, make sure the switch was installed properly, with the shield in place and all. At least it lets you go longer on the switch then the black one :D