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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Topic started by: BillB on April 19, 2013, 09:49:49 am

Title: Changing 4x4 to 2wd
Post by: BillB on April 19, 2013, 09:49:49 am
Hey guys, I have a 81 swb 4x4 frame with suspension, the transfer case is thrashed, front diff is shot etc....to make a long story short, I have access to a  2wd 81 3/4  lwb, want to know if the front suspension from the 3/4, 2wd will adapt to the 4x4 frame converting from a 4x4 to 2wd?  Thanks in advance, finding out here whether this can be done will sure save time and frustration if it cant be done :)
Title: Re: Changing 4x4 to 2wd
Post by: pholliday1 on April 19, 2013, 03:00:54 pm
O....Anything can be done the general school of thought is that is requires a lot of fab work. So if you have those items available then have at it.However its not considered an "easy" project what so ever
Title: Re: Changing 4x4 to 2wd
Post by: BillB on April 19, 2013, 08:01:20 pm
Thanks for the info, was hoping for a bolt on conversion, maybe time to go back to the thinking board. :-\
Title: Changing 4x4 to 2wd
Post by: Tx_Phil on April 19, 2013, 08:40:51 pm
I'm going to show my ignorance here but could you just pull the gut out of the front diff and drop the drive shaft and run it as a 2wd?

Have you looked into salvage yard parts or pick-part stuff?  I'm guessing you could repair the diff and transfer case cheaper than converting to a stock 2wd suspension when you factor in time and frustration and such.
Title: Re: Changing 4x4 to 2wd
Post by: zieg85 on April 19, 2013, 09:02:05 pm
A donor frame, nice sharp air chisel and grade 8 bolts.  I can't imagine it would be that hard to do.  Very time consuming though.  Captkaos has a build thread on here doing that same thing on a Blazer.
Title: Re: Changing 4x4 to 2wd
Post by: Irish_Alley on April 20, 2013, 07:03:57 am
most if swapping will swap from a 4x2 to 4x4 not this way around. its been over 10 years since i looked at my 86 4x2 can barely remember anything about it. but if i had to i would do like phil said and gut everything and run her
Title: Re: Changing 4x4 to 2wd
Post by: BillB on April 20, 2013, 09:15:29 am
What I am trying to do is put together a 81 swb stepside 2wd, I have all I need except the swb frame is  4x4 running gear. I am hoping to remove the front axle, springs, etc and use the front  suspension from a donor 81 3/4 lwb 2wd. The 3/4 lwd frame is in another location so I cannot compare the 2 side by side, I am thinking  the frames are  identical so I will be able to make the switch. I will pick up the 3/4 frame next week so will compare then, was just hoping that this swap had been done before so I would have my ducks in a row before I start.   Thanks.
Title: Re: Changing 4x4 to 2wd
Post by: Irish_Alley on April 20, 2013, 09:55:59 am
the frames are the same from what i compared 1/2 ton to 3/4 ton. might have to drill holes and so on but i think its all pretty simple. done a 4x2 to 4x4 and it was all pretty much cut and paste
Title: Re: Changing 4x4 to 2wd
Post by: Jason S on April 20, 2013, 11:09:59 am
Are you going to keep the 8-lug brake/wheel setup, essentially building a 3/4-ton shortbed stepside truck?
Title: Re: Changing 4x4 to 2wd
Post by: Irish_Alley on April 20, 2013, 12:18:27 pm
lol the little details; not a with 1/2 ton front he would also have to swap rears or the axle shafts if possible
Title: Re: Changing 4x4 to 2wd
Post by: BillB on April 20, 2013, 04:28:31 pm
Now to show just how quickly things can change in my square body world, if I were to replace the 4x4 front axel setup, hub to hub do I need to match gear ratios (front to rear)?  Sorry to show my ignorance here but As you can see I know very little when it comes to 4x4s. (Just an example of how little I do know) lol.   :D
Title: Re: Changing 4x4 to 2wd
Post by: zieg85 on April 20, 2013, 04:35:13 pm
The gear ratios need to match if you are going to use the 4 wheel drive.
Title: Re: Changing 4x4 to 2wd
Post by: BillB on April 20, 2013, 05:03:52 pm
Thanks zieg85, now for another show of ignorance,is there identification marks on the axels to show the gear ratio? If so where are they located?
Title: Re: Changing 4x4 to 2wd
Post by: zieg85 on April 20, 2013, 05:53:09 pm
Only sure way to tell is take the diff cover off and look at the ring gear, rotate it around, you will see 2 numbers, for example 40/13 which is a 3.08.  If they are original to the truck and you have the sticker on the inside of the glove box door it will tell you or give you a RPO code like a HE3 for example.  Report your findings.

http://www.rpocodes.com/GM-RPO-codes/gmrpocodesGthroughM.html should help you know what you have or originally came in the truck
Title: Re: Changing 4x4 to 2wd
Post by: Blazin on April 24, 2013, 12:54:36 am
If you plan to swap the 4x4 over to a 4x2 you also need to swap the rear spring shackles / hangers as well to 2 wheel drive pieces.
Title: Re: Changing 4x4 to 2wd
Post by: Jason S on April 24, 2013, 04:34:22 pm
Exactly what is wrong with your current front differential and transfer case? 
Title: Re: Changing 4x4 to 2wd
Post by: frotosride on April 24, 2013, 09:43:14 pm
Only sure way to tell is take the diff cover off and look at the ring gear, rotate it around, you will see 2 numbers, for example 40/13 which is a 3.08.  If they are original to the truck and you have the sticker on the inside of the glove box door it will tell you or give you a RPO code like a HE3 for example.  Report your findings.

http://www.rpocodes.com/GM-RPO-codes/gmrpocodesGthroughM.html should help you know what you have or originally came in the truck

ZEIG-Thanks for the website. I Knew there was one out there but I couldn't remember it for the life of me. I just finishes decoding every code that was listed and learned a lot about my truck. The best part is that it is all still original well 97.386% original...Oh and I got positract..wonder if that's just the rear diff though.
Title: Re: Changing 4x4 to 2wd
Post by: frotosride on April 24, 2013, 09:46:54 pm
Oh and good luck on the conversion. I bet that aslong as you can get the control arm frame mounts off of the donor and tack them in right on the money it shouldn't be too bad but this is definitely not just a bolt in. But Keeping it 4x4 is the best idea IMOP.
Title: Re: Changing 4x4 to 2wd
Post by: Protouring82C10 on April 30, 2013, 07:08:24 pm
Here is a good start for you and i will ship it if you're interested.

 http://desmoines.craigslist.org/pts/3776392140.html

My bad, I didn't see that you had a donor truck and good luck on the conversion.