|11-22-2009, 01:25 PM||eBay Motors #1 (permalink)|
Join Date: Nov 2009
Allison shift problem cured thanks all
Hi All, Newbie here. I was able to troubleshoot my 02' 2500HD Dmax LB7 5spd auto, approx. mileage 150,000K/90,000Miles .Thanks to all of the awesome articles posted - big thanks. The symptoms were as follows: over the last week the shift display wasn't showing that I was in Drive. I could shift into 3 and it would light up over the 3 but when shifting back to D, it remained unlit. The problem then amplified while plowing snow, I shifted from fwd to rev and there was a delay, then big clunk. It did this a couple times then went away. The lack of indication problem occurred through the week culminating with blocking traffic in two directions trying to back into my driveway. I shifted her into reverse and she clunked again then nothing. tried to shift from drive to reverse, didn't matter what gear I chose, it wasn't moving. The check engine light came on this time as well. Worse yet, I had to pull it into the driveway with the wife's Ford! I had thought the worst, the transmission was pooched! Thats when I googled the problem and these forums came up. It took only a few minutes and I saw a similar problem had occurred and the NSBU (Neutral Safety Backup) switch was the culprit. With a little more googling I found some pictures and the actual part number (29540479) heres the link: (If it doesnt work just google NBSU switch.)Allison 1000 Series NSBU Switch pictures from cars photos on webshots
I replaced the switch, the problem was solved. It costs approx $280 - alot cheaper than a new tranny! Replacement instructions came with the switch kit, easy to follow and only two plugs, two bolts and the linkage arm to disconnect.
|11-22-2009, 10:29 PM||eBay Motors #2 (permalink)|
Join Date: Oct 2006
Location: Irwin PA
Welcome to the forum!
Awesome! Im glad we could help you out :rockin
2006 Silverado 2500HD LBZ CC SB
Exterior: Escalade Handles, Front windows tinted to match the rear, painted bumpers & mirrors, billet grille, 305/50/20 Cooper Zeons on BMF Novakanes Death Metal, Cognito Braces, Stainless Sleeves, Train Horns
Interior: 4 Kicker 10in Subs in 2 custom box's, Autometer Ultra lite II Pyro and Boost gauges, Aeroforce Interceptor Gauge, HID Lows & Fogs, Painted accents
Performance: EFI Live Tuned by Blackout Performance, Custom Blackout Performance S475 over stock twins, 45 over stock injectors, MBRP Turbo Back Stainless Exhaust (Straight piped), Raptor Lift Pump, AFE Filter, GMAX6 kit with Suncoast 1057 converter installed by Blackout Performance
1999 Ford F-550 PowerStroke ''Wrecker'' **Jerrdan bed, S&B Intake
|02-19-2012, 09:52 AM||eBay Motors #6 (permalink)|
Join Date: Dec 2010
Thanks Mike L - problem I have is the truck will not shift into high gear - and the dealer can't figure it out - says go to Allison (at 35 mph). I suspect Neutral Safety Backup Switch as they do get crudded up and I haven't put back my fenderwells since other work. I have a p/n 29541852 - 1 connector. Trying that tomorrow as it is a $50 part.
Would like to put an aluminum cover on but someone said might get hit by a rock - steel is better (????). I did lose my tranny cooler, had to suck it up and have dealer replace - looks like a mickey mouse unit.