Allison 5sp: Odd Symptoms involving Trans and T-case

[Bfever74]

Truck is an 04 LB7. 230k miles. Original set of symptoms....
1) Service 4WD
2) No Cruise Control
3) P0500
4) P0700
5) ABS Light
5) No Speedometer reading on CTS2, but dash working fine
6) 4Lo showing on 4WD switch, or sometimes neutral

So far, I have replaced the T-case because it blew. Literally. Broke out of the casing. Also replaced the NSBU, Vehicle Speed Sensor (on t-case), and the 4WD switch. Symptoms stayed away for 4-5 weeks. Now I get them intermittently. Sometimes my cruise works, sometimes not.

caveat to ABS light - Came on after changing UCA's last spring. I'm going to clean them and see if that fixes it, if not I'll replace them. But that requires time, which I don't have a lot of.

I'm curious to hear any suggestions on how these issues could or could not be related. I would rather throw parts at it myself than take to a shop to pay labor. Since the truck is 13 years old with a ton of miles, the parts probably need to be replaced anyway. So I don't get too worked up if I throw a part at it and it doesn't fix it (as long as it's not too expensive)

ps Roxyfever and I have both done some research on this without any obvious answers. Well, him more than me. One unknown is if the ABS sensors in the front wheels can cause the vehicle speed sensor code to light up.

I'm all ears. Thanks!

 

[roxyfever]

Anyone have any ideas?

 

[mac2881994]

I had a front wheel speed sensor rub the wire in two on my 04.5 LLY and it light up the ABS light on the dash. I don't remember if it threw any other codes. One of the plastic clips that hold the wire to the stock UCA's broke and allowed the wire to rub on the inner sidewall until it broke in two. It would randomly light up the ABS light when hitting big bumps prior to it completely breaking.

 

[PureHybrid]

Do you have a scanner that will read codes from all the modules? Should be something stored in the transfer case module if your service 4wd is still coming on.

 

[roxyfever]

I think all he has is the cts2 for a code reader. What reader would read all the modules?

 

[PureHybrid]

My v2 scanner will, a good snapon or tech2

 

[Bfever74]

I had a front wheel speed sensor rub the wire in two on my 04.5 LLY and it light up the ABS light on the dash. I don't remember if it threw any other codes. One of the plastic clips that hold the wire to the stock UCA's broke and allowed the wire to rub on the inner sidewall until it broke in two. It would randomly light up the ABS light when hitting big bumps prior to it completely breaking.

Thanks for the info. I'm pulling the front wheels off this weekend, hopefully I can figure something out. I new the sensors affected ABS (kinda obvious I guess), but I didn't know the vehicle speed circuit (speedometer and cruise control) would require any input from those two things.

 

[Bfever74]

My v2 scanner will, a good snapon or tech2

I just have a PPE Programmer and a CTS2. I have noticed that the PPE clears the codes better. Sometimes the CTS2 won't clear them. It's weird.

I would love to know why the Service 4WD keeps coming up on the DIC. I need to have that read using one of the items you listed.

Thanks!!