Allison Problems no 4th-5th anyone?

Hotair · December 20, 2003

Driving my truck to work the other day and the Door Locks unlocked while doin 40 mph. then i noticed my indicator for my gear selection was not working. Now i only have 1st - 3rd and reverse. Anyone ever have this problem before? Goin to the dealer on Monday, they think is some sort of control box.... any ideas?

Bob

kylant · December 20, 2003

NSBU switch!

Neutral saftey backup switch. very common problem. go over to thedieselpage.com and check out all the threads on this.

good luck

bigdogs · December 20, 2003

Not to ask a stupid question but how do you know you are in 5th gear anyway being the selector just shows D321

f7_ditch_jumper · December 21, 2003

count how many times the tranny shifts from a complete stop.

Hotair · December 21, 2003

Thanks Kylant. the diesel page was very informative. now i have an idea what to expect. hopefully they have the part instock! Thanks again!

bigdogs · December 21, 2003

Ok thanks I knew you could do that but then after reading that, thought maybe I was missing something and it showed it somewhere.

BlackSilver · December 22, 2003

count how many times the tranny shifts from a complete stop.

That may not work! Unless it's very cold out, or you're pulling and in "Tow/Haul", I think the truck starts out in 2nd gear.

kylant · December 22, 2003

hotair,

no problem. make sure you get the TAN switch. this is the updated one. they may need to clear your TCM for any trouble codes

good luck

Roofer · December 22, 2003

count how many times the tranny shifts from a complete stop.

That may not work! Unless it's very cold out, or you're pulling and in "Tow/Haul", I think the truck starts out in 2nd gear.

I think you're right on the cold part. If the tranny is still under 100, 1st and 5th don't engage.

tbyrne · December 26, 2003

I noticed the other day that mine felt like it was "catching up" when I came to a stop. Got down to about 5 MPH and felt it bang into 1st. Actually I thought I could feel it hit 2nd and then bang 1st within about 2 seconds. I haven't driven the truck much since then to pay attention to this.

Tom

2002 8.1 Silverado HD - Comp Cam, TOGs headers, Volant induction, Direct Hits ignition, 8" lift 18" wheels/tires + more

2002 8.1 Suburban -Intercooled Whipple supercharger, TOGs headers, Volant induction, 22" wheels/tires + more - 407hp/558 ft-lb torque at the rear wheels.