89 2wd cab to 90 4x4 frame. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DINS 1 · 11-06-2022, 11:14 PM

how much wiring do i have to do to make the 89 2wd cab work on the 90 4wd frame both are 5.7 motors both are manual window lock and A/C trucks. the 89 has a 700r4 and the 90 has ath400.. i know i will have to move the 4wd shifter. that is where the wiring needs to be added to the 89. something might have to change for the transmission.

**Palf70Step** · 11-07-2022, 11:56 AM

Me, swap the wiring harness from the 4wd cab to the new cab. Not sure, there might be a high humb for the 4wd, which is not in 2wd. Never had a 4WD version of these trucks, so not sure.

**special-K** · 11-08-2022, 07:44 AM

I can't say for sure because I've never tried this. But the only thing I can think of is the differences in speed sensors on transmission, if any difference at all. The transfer case is manual. The only thing electric is the indicator. I'm sure that's simple wiring if you don't have the harness. I don't know about floor hump, but you have both to check

1976gmc20 · 11-10-2022, 12:28 PM

Quote:

The transfer case is manual.

The front axle connector is electric, run off a switch on the TC lever.

Or you could just lock it in permanently with a 1" piece of 3/4" plastic pipe like I did. Just like running with the hubs always locked in, or like my old jeep that turns all the time anyway from the factory.

11-06-2022, 11:14 PM	#1
DINS 1 Registered User Join Date: Apr 2000 Location: Webster City, Iowa USA Posts: 572	89 2wd cab to 90 4x4 frame. how much wiring do i have to do to make the 89 2wd cab work on the 90 4wd frame both are 5.7 motors both are manual window lock and A/C trucks. the 89 has a 700r4 and the 90 has ath400.. i know i will have to move the 4wd shifter. that is where the wiring needs to be added to the 89. something might have to change for the transmission. __________________ Wade "DURAMAX BURB" Burb on 2004 chevy 2500HD 4x4 Duramax chassis Long term project 2004 2500HD 4x4 crew cab GMC Duramax 4" lift 35's 79 RS Camaro

11-07-2022, 11:56 AM	#2
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 46,640	Re: 89 2wd cab to 90 4x4 frame. Me, swap the wiring harness from the 4wd cab to the new cab. Not sure, there might be a high humb for the 4wd, which is not in 2wd. Never had a 4WD version of these trucks, so not sure. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

11-08-2022, 07:44 AM	#3
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: 89 2wd cab to 90 4x4 frame. I can't say for sure because I've never tried this. But the only thing I can think of is the differences in speed sensors on transmission, if any difference at all. The transfer case is manual. The only thing electric is the indicator. I'm sure that's simple wiring if you don't have the harness. I don't know about floor hump, but you have both to check __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~



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