4wd conversion

01 Sierra 4.8

New member
Dec 13, 2015
28
1
3
Hey guys I have a 2002 duramax getting ready to do a 4wd conversion before too long, have all of parts just looking for passenger side bushings but other then that everything's all good to go. Figuring out the wiring at the moment I emailed Ben at BT diesel wasn't able to get the wiring harness made but I have the tcase harness and dash harness out of another truck couple wires I'm unsure of, first there's pink, purple with white stripe and grey from the buttons on the dash that I'm unsure of where they go and from the light blue kinda turquoise plug that goes to the tccm there's 2 wires (turquoise with white stripe and brown) that I'm unsure of. I have everything else figured out for the dash harness. Second is I read something to do with 4wd low you have to wore something up or tap into another harness, if anyone could help me out it'd be much appreciated thanks for your time
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,492
472
83
Central OH
Can't help you with the wiring, Ben threw a harness together for me right before he quit doing them.

The bushings can't be bought from GM, I tried, it's part of the frame assembly. Either get some from a donor truck, or like I did was make bigger holes to get some poly bushings to fit. (I trimmed the rear bushing to fit the stock hole)
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,610
1,865
113
Mid Michigan
I still think you could possibly use a leaf spring bushing for it. There are two threads here already about 4wd conversions, I think one of them had info about what he used for it.

As for wiring, no help. Are you trying to use a 263 push button case? Why not use a manual one?

Moved to TC/Axles/Drivetrain, too.
 

jpowel29

Member
Feb 1, 2008
780
0
16
Bentonville, Arkansas
It has been a long time since I looked at this on mine but I have in my notes that the "b" terminal from the t-case selector switch goes to pin 26 on ecm for 4wd signal and the "a" terminal goes to ecm pin 72. That should let the computer know when you are in 4LO, I believe. The signal wire from t-case should be able to turn on the 4wd light on instrument cluster. Again this has been quite a while back so verify this before diving in but that I what I kept.
 

01 Sierra 4.8

New member
Dec 13, 2015
28
1
3
I still think you could possibly use a leaf spring bushing for it. There are two threads here already about 4wd conversions, I think one of them had info about what he used for it.

As for wiring, no help. Are you trying to use a 263 push button case? Why not use a manual one?

Moved to TC/Axles/Drivetrain, too.

I've searched high and low for a manual case everyone that has one doesn't want to sell
 

01 Sierra 4.8

New member
Dec 13, 2015
28
1
3
Does anyone have access to all data to get the plugs might be able to figure out the wires I'm trying to find
 

01 Sierra 4.8

New member
Dec 13, 2015
28
1
3

CarolinaHD

Member
Feb 8, 2011
969
6
18
NC
2e5769b61a7d9e5bdf3d2c0a920c94fd.jpg


The harness on the bottom is the front actuator harness and the one on top is for the vss and transfer case. The single row 4 pin connector plug into each other.


20170228_102759.jpg

0c3442684488f4599105ef95e7158be1.jpg

Actuator harness connectors.




ba0ecc27c8141c386a6b7c00abf12648.jpg


2364460854a15de68bab3312e5bb4ab6.jpg

Orange connector plugs into actuator harness, purple/blue connector plugs into the truck side harness under the fuse box.

e13be19e45bcd94a67bf4b107023d170.jpg


5952ebce6cf82af8fba4a5d8fc82e00a.jpg


9e280135752d07f098dc22de6d3a8acc.jpg


The connector on top that is not currently plugged into anything gets connected to the Allison Transmission harness.
 

Attachments

  • 20170228_102759.jpg
    20170228_102759.jpg
    57.7 KB · Views: 10

CarolinaHD

Member
Feb 8, 2011
969
6
18
NC
This is all for a 2006 lbz so wiring pin locations may be a little different but the harness should be the same.
 
Last edited:

01 Sierra 4.8

New member
Dec 13, 2015
28
1
3
Also I'm sure the orange wire coming out of the smaller tccm plug goes to the 4wd fuse on the drivers door I'll tap into that but I'm going to need another wire to complete the circuit I'm not sure where I will have to run the wire to
 

CarolinaHD

Member
Feb 8, 2011
969
6
18
NC
Upper bushing mount welded in

0f8b1f4c0fea1b9d7cbd44603aaa399e.jpg


9bcc3bfae1d20bd8ef26a0d91b668aef.jpg


Lower bushing hole already in place from the factory

e1b2a052f73f848119d7ee6b8f4a79f9.jpg


I cut the 2 factory brackets off a frame I had for the drivers side. Someone could easily fabricate the brackets.

9f30704fe59c80bf0ab1fe7e69ba0aaa.jpg


703c8b7df46c591e8b343d98ceeb131c.jpg


On this lower mount you'll need to remove the 2 pieces of tubing that the bolts run through for the 2wd brace.

d442ee0662bde845d070c2aa6d563fcc.jpg