GM Truck Club Forum banner

1 - 20 of 20 Posts

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #1 (Edited)
Here's my first post here, so let's get to it...

Ok, I'm about to purchase a 1991 Chevy Suburban 2WD with the standard SBC 350 motor in it. I would really like to have a 4WD vehicle, but since I'm getting this truck in immaculate condition and at a steal price level, I can't turn it down. I've done a little bit of researched, talked with a few of my buddies who are mechanics, and it looks pretty good that I will probably be able to convert this truck to 4 wheel drive rather painlessly. Of course, however, I want to confirm it with the experts first. :) Since it's a '91, it's still using the old manual-style transfer case, which shouldn't require any wiring. So, it looks like, it's going to be a moderatly simple job of taking the front end apartn, dropping the old driveshaft, putting the front axle in the front with CV shafts, locking hubs (I hope I can' find auto-locking hubs for it?), mounting the transfer case, and putting 2 new driveshafts in. It just seems that it can't be THAT easy to do, I've got to b missing something.. Thanks for any advice anyone can give to me.
 

·
Registered
Joined
·
2,630 Posts
The only thing you're missing is that your entire front suspension, and steering will need to be converted as well. Other wise I think you've got it covered.

You will have some minor wiring to do, but nothing too involved.
 

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #3
I'm going to have to replace the entire front suspension? I have the hydrostatic steering (or whatever the non-rack and pinion one is called). Ugh, I was hoping I wouldn't have to modify those 2 components. That's where it starts getting hairy and somewhat painful IMHO.
 

·
Registered
Joined
·
2,630 Posts
At the very least the suspension needs to be changed. The current configuration is probably coil springs. You'll never be able to get the CV axle through because the coil will block the path.

You'd need to replace:
  • Upper, and lower control arms
  • Sway bar
  • Shocks
  • Torsion bars
  • Steering knuckle/hub unit
  • new brake calipers?? (possible size difference from 2wd)
  • Tie rods, and drag-link?? (geometry of steering may be different from 2wd)
  • Cross-member may need to be replaced to accept torsion bars.
Unfortunately it's a bigger job than just throwing in the drive train.:frown:
 

·
Administrator
Joined
·
4,886 Posts
I've known guys who have started down this road and have had good luck and bad luck with the process. One found a wrecked 4WD vehicle of the same year that was rolled over and burned, but the front end was in good shape. He got it for a song and moved pieces over, took about a month and he had himself a 4x4.

Another friend started into the project hoping for a simple job, didn't understand what it took and I think ended up reversing himself mid-way and returned to a 2WD truck, much to his embarrasment when we all went off roading!
 

·
Premium Member
Joined
·
1,625 Posts
4X4 changeover

I've known guys who have started down this road and have had good luck and bad luck with the process. One found a wrecked 4WD vehicle of the same year that was rolled over and burned, but the front end was in good shape. He got it for a song and moved pieces over, took about a month and he had himself a 4x4.

Another friend started into the project hoping for a simple job, didn't understand what it took and I think ended up reversing himself mid-way and returned to a 2WD truck, much to his embarrasment when we all went off roading!
Not sure but aren’t the trany’s different.

I know my 79 GMC has a different trany, shorter tail shaft than the 2 wheel drive version would have, like I said I’m not sure.

Anyone?
 

·
Registered
Joined
·
2,630 Posts
I was just reading your other post about the paint, and I saw your signature, and it hit me.
You're going to lose your 3.08 gear ratio. You'll need to have a matching front gear. So if you wanted to keep the ratio, you'd need to find a front 3.08. I'm pretty sure that gear ratio was not an option for any 4x4's.

Also as far as your front suspension, don't limit yourself to finding a junked burb w/4x4. I'm pretty sure you can pull the parts from neighboring years 90-92 4x4 pick-ups. Actually from what I'm seeing in my book the parts are the same going back to 1988.

In my area there is a publication called "The want ad" basically people put ads in to sell their stuff. On the last 2 or 3 pages, they have a listing of vehicles being sold for parts. I'm sure you have something similar in your area. A lot of those vehicles are usually sold w/out engines. Perfect for someone like you!!:great:
 

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #8
TrailLeadr, are you suggesting that I stay with the truck I have, and find a junked burb with 4x4 and pull the parts from it? That sounds to be a great idea, as I have a body in perfect condition, with the exception that it has virtually no paint left on it. I can live with losing my 3.08s, since it's a weekend warrior, and I can accept the fuel mileage loss on something I only drive on the weekends. I'll have to look down the RPO code list, I'm sure I can find a 4x4 with something like 3.83s or 4.12s, and if not, screw it, it's a weekend warrior meant for fun, let my gas mileage (which is only 14mpg hwy/city mix) go out the window. :)
 

·
Registered
Joined
·
2,630 Posts
TrailLeadr, are you suggesting that I stay with the truck I have, and find a junked burb with 4x4 and pull the parts from it? That sounds to be a great idea, as I have a body in perfect condition, with the exception that it has virtually no paint left on it. I can live with losing my 3.08s, since it's a weekend warrior, and I can accept the fuel mileage loss on something I only drive on the weekends. I'll have to look down the RPO code list, I'm sure I can find a 4x4 with something like 3.83s or 4.12s, and if not, screw it, it's a weekend warrior meant for fun, let my gas mileage (which is only 14mpg hwy/city mix) go out the window. :)
It's certainly do-able to go from 2wd to 4wd, but just know you have your work cut out for you.
If you plan on using your weekend warrior for off roading, you'd be better of with 4.10 ratio. Less strain on the drivetrain.
I would say if you're serious about the conversion it's picking up a junker w/4wd is probably the easiest way to go. Especially if your body, and engine are in good condition.

Maybe you'll even find someone on Ebay close to your area.
 

·
Super Moderator
Joined
·
6,542 Posts
If your serious about a 2wd to 4wd conversion I agree, source a trashed Suburban with good running gear (Frame, Axles, Transmission, and Transfercase) Set your good body on the donor frame, use your engine and the donor trucks frame, transmission, axles, and transfercase. You can then sell your rolling chassis, if the donor truck has a body throw that in the deal. Trying to fab all the necessary brackets and mounts for this conversion is a chore for an experienced fabricator, not to mention trying to get the spring and steering geometry correct. I've done a couple 2wd to 4wd conversions and I'd much rather source a 4wd frame for this type job.
 

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #11
I think I may have sourced a 4wd sub. I still don't have any information on specfics about it, other than the motor's dead, or something of the sort. I'm hoping the body on it is in good condition, and with the barn doors, but we shall see. I still need to get more info on it, including cost, but I will keep ya'll informed on the progress. Also, how hard is it to pull the body off of a burb? obviously it isn't as easy as pulling the motor, unbolting the chassis to body bolts and picking it up off the truck. Does anyone have a procedure written up or anything for this? Thanks
 

·
Super Moderator
Joined
·
6,542 Posts
Actually it's not real hard to separate the body and frame. Most of the wire harness, except for the engine harness and leads to the trans & T-case stay with the body, and the fuel lines are attached to the frame.
Disconnect the steering, A/C, brake, throttle cable, engine bay wireing, fuel tank filler, and a couple of grounds and the bodys ready to be lifted.
Some tips from when I swapped the body/frame on my 97 are:
Unless you have a crane to lift with strip the interior and remove all the doors and fenders.
Have the new frame ready to accept the body, we parked the trucks end to end lifted the donor frame body onto a flatbed and then the keeper body onto its new frame.
It takes about 8 guys to lift a stripped suburban shell.
If you cant find enough people to do the lift you can jack the body up higher than the highest point on the frame, support it on saw horses then roll the frame out and roll the new frame under, I've used this method before also.
Prepping the body for removal takes about 8 hours.
 

·
Registered
Joined
·
12 Posts
TrailLeadr, are you suggesting that I stay with the truck I have, and find a junked burb with 4x4 and pull the parts from it? That sounds to be a great idea, as I have a body in perfect condition, with the exception that it has virtually no paint left on it. I can live with losing my 3.08s, since it's a weekend warrior, and I can accept the fuel mileage loss on something I only drive on the weekends. I'll have to look down the RPO code list, I'm sure I can find a 4x4 with something like 3.83s or 4.12s, and if not, screw it, it's a weekend warrior meant for fun, let my gas mileage (which is only 14mpg hwy/city mix) go out the window. :)
an '88-'94 donor vehicle should be your best bet. You can also go to a K1500 truck for the parts needed. Since it sounds like you're going to really use this truck, does that mean you'll be adding a lift kit to it or leave it stock? If you're going to lift it, i'll save you a bunch of time here. Get a trans and t-case assembly out of a 4x4, you'll need the drive shafts out of it too.

Now get yourself a dana 44 or 60 front end. Now buy the SAS kit from off road unlimited and go to a straight axle up front. You can have your lift built into your new front leaf springs. Now take the stock 10 bolt rear and throw it in the garbage. Get a 9.75" 14 bolt rear out of a K2500 suburban or 10" 14 bolt, and do the gears front and rear according to the tires you're going to run.

This is going to be the cheapest way to get where you want to go, unless you can find a rolling chassis and swap every thing over, but you'll still end up with a stock height truck and a weak IFS.

Not sure on the end result but hopefully that helps you out. If you're still looking in about 3 months, let me know because i'll be completing my SAS swap on my '94 K1500 and i'll have some extra parts left over :biggrin:
 

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #14
an '88-'94 donor vehicle should be your best bet. You can also go to a K1500 truck for the parts needed. Since it sounds like you're going to really use this truck, does that mean you'll be adding a lift kit to it or leave it stock? If you're going to lift it, i'll save you a bunch of time here. Get a trans and t-case assembly out of a 4x4, you'll need the drive shafts out of it too.
I'm having a little difficulty understanding what you're saying here. It appears that at first, you are suggesting to use a donor 4x4 chassis. Then later on in the paragraph, you're suggesting that if I really plan on doing some serious off-roading, lift it and use the existing chassis I have that is currently 2wd, and just slap a tranny and transfer case in from a 4x4.

That being said, I don't plan to do a lot of "mudding" but this truck is frequently driven "off-road" up at the boy scout camp, which is nothing but red mud. When it rains, the red mud gets very sloppy and the rain casues 5-14" deep gulleys to form in the road from erosion. At the current height of the burb, if for whatever reason, I have to cross those gulleys at a non-optimum angle, I scrape my trailer hitch on the ground, which has made me consider lifting it.

So, you are pretty accurate in your assumptions so far. I think that I want to do a suspension lift of maybe 4-6 inches, but for now keep the stock tires, since my current rubber is still at half-life and I don't have the excess cash to throw on tires at this moment. If I can keep the existing chassis, and convert it to a 4x4 without having to drill new holes in the frame, I think I'm game for it.

I can not seem to find anything that meets the terms of "SAS kit", but I'm guessing it's a suspension lift kit? I am also guessing that you are suggesting the SAS kit in conjuction with the 4x4 conversion on my existing frame because that would eliminate, or at least minimize the need to fabricate custom brackets and such on the front end, making life easier.

Thanks for all your help so far.
 

·
Super Moderator
Joined
·
6,542 Posts
I can not seem to find anything that meets the terms of "SAS kit", but I'm guessing it's a suspension lift kit? I am also guessing that you are suggesting the SAS kit in conjuction with the 4x4 conversion on my existing frame because that would eliminate, or at least minimize the need to fabricate custom brackets and such on the front end, making life easier. Thanks for all your help so far.
"SAS" is a term used by off-road crowd, it means Solid Axle Swap. Not the best description to use for this build, it usually means swapping a solid front axle in place of an IFS system. Your looking to add an axle to the front of a truck that could've come from the factory with a solid axle. There are kits to put a front axle under your truck but as I mentioned before unless you have a lot of experience with steering set-ups and axle geometry it's a nightmare. These set-ups are great for someone into hardcore wheeling that's a good mechanic, you can spend a lot of time getting things straight and working correctly. Also the 4x4 frames and 2X4 frames have some differences, 4x4 being a little stronger in the front. A typical SAS kit runs about $1000 and doesnt include the running gear, just hardware and directions, it includes welding and drilling on your frame. For your use I still think you'd be better off swapping to a rolling 4x4 chassis. You can add a lift later and use aftermarket parts designed for factory GM suspension.
 

·
Registered
Joined
·
12 Posts
"SAS" is a term used by off-road crowd, it means Solid Axle Swap. Not the best description to use for this build, it usually means swapping a solid front axle in place of an IFS system. Your looking to add an axle to the front of a truck that could've come from the factory with a solid axle. There are kits to put a front axle under your truck but as I mentioned before unless you have a lot of experience with steering set-ups and axle geometry it's a nightmare. These set-ups are great for someone into hardcore wheeling that's a good mechanic, you can spend a lot of time getting things straight and working correctly. Also the 4x4 frames and 2X4 frames have some differences, 4x4 being a little stronger in the front. A typical SAS kit runs about $1000 and doesnt include the running gear, just hardware and directions, it includes welding and drilling on your frame. For your use I still think you'd be better off swapping to a rolling 4x4 chassis. You can add a lift later and use aftermarket parts designed for factory GM suspension.

I am referring to the Straight Axle Swap, and unless you've done one in the past or have done a GM suspension lift kit, you'd be better off not advising him. I have done both before and for a mostly off road 4x4, the dana 60 is vastly superior in every way to the factory IFS setup. What I was trying to get across is that if you're going to do a <2" lift, and have a readily available chassis, then go that route because it's going to be the cheaper and seemingly easier swap to do. If you're going to lift it 4-6" like you said, you're going to buy a stock height suspension and pay for that, then you're going to either swap chassis or unbolt, cut, weld the new chassis to the old one. In the end of all this work, you wind up with what? a stock height 4x4, then go out and to get a QUALITY 6" lift, you're out 4k for that.

Plan B as I suggested if you're going to lift it, is to buy the parts already lifted. So here is my suggested parts list now knowing you want a 4-6" lift in the end.
Dana 44, or 60. You can source a junker out of a bunch of vehicles. Be sure you either a: match the existing gear ratio of your rear end, or b: (suggested) get matching ring and pinion kits front and rear for your expected tire size. 6" you can fit 35's.
ORU correct SAS kit made for your vehicle ALREADY HAS THE CORRECT GEOMETRY and parts. This can be found here.
Front leaf springs can be had from Atlas or Deaver to your specifications. ORU can help you spec them out.
Front crossover steering kit from ORU
Trans with t-case from a donor vehicle.
Front drive shaft. ORU can help you here again, they have done a TON of these conversion kits.

Compare the pricing before you start. For 99% of people the SAS is the way to go, for some that have bent frames, etc.. it makes more sense swapping out the whole chassis. You still have to deal with the whole licensing thing with the chassis swap, and that may or may not be a whole other nightmare for you. I don't know, you'd have to check your local laws and regulations about a chassis swap and how it effects the titling of the vehicle.
 

·
Registered
Joined
·
20 Posts
If your serious about a 2wd to 4wd conversion I agree, source a trashed Suburban with good running gear (Frame, Axles, Transmission, and Transfercase) Set your good body on the donor frame, use your engine and the donor trucks frame, transmission, axles, and transfercase. You can then sell your rolling chassis, if the donor truck has a body throw that in the deal. Trying to fab all the necessary brackets and mounts for this conversion is a chore for an experienced fabricator, not to mention trying to get the spring and steering geometry correct. I've done a couple 2wd to 4wd conversions and I'd much rather source a 4wd frame for this type job.
my dear friend,,,a friend of mine told me he didnt want advice he wanted money,,,,,if you do what you are talking about you gonna need some bucks,,and will have to go to mass everyday {confession},,what your gonna have to pour into it you can go find a 4 wheeler,you probably have bought the 2 wheel drive surb. thats ok,,,fix it up and sell it and look for a 4 wheel,,just some advice my dear friend from a cajun,,abuelito
 

·
Super Moderator
Joined
·
6,542 Posts
I am referring to the Straight Axle Swap, and unless you've done one in the past or have done a GM suspension lift kit, you'd be better off not advising him. I have done both before and for a mostly off road 4x4, the dana 60 is vastly superior in every way to the factory IFS setup.

Dana 44, or 60. You can source a junker out of a bunch of vehicles. Be sure you either a: match the existing gear ratio of your rear end, or b: (suggested) get matching ring and pinion kits front and rear for your expected tire size. 6" you can fit 35's.

ORU correct SAS kit made for your vehicle ALREADY HAS THE CORRECT GEOMETRY and parts. This can be found
First "Solid axle swap" and "Straight axle swap" are two terms for the same meaning!!

And yes I've done many lifts and swaps, recently on GM vehicles.

No one doubts a Dana 60 is superior to a Dana 44, in price also, and both are in some ways superior to IFS (which you may notice his truck does not and could not have).
You may have missed the point on this whole swap, it wasnt to spend lots of money to make an off-road killer, it was to make a dependable mild off-road truck that may be lifted sometime later.
ORU has a great kit, I've used them quite a few times, but no matter how great the kit is it doesnt simply bolt into existing holes, which was posted as a concern. The ORU kit (as does any kit) also requires accurate measuring for placement to ensure you have correct geometry and no binding.
Before advising him you'd be better off reading deeper into his post to find what he's really trying to do with his truck.
 

·
Super Moderator
Joined
·
6,542 Posts
my dear friend,,,a friend of mine told me he didnt want advice he wanted money,,,,,if you do what you are talking about you gonna need some bucks,,and will have to go to mass everyday {confession},,what your gonna have to pour into it you can go find a 4 wheeler,you probably have bought the 2 wheel drive surb. thats ok,,,fix it up and sell it and look for a 4 wheel,,just some advice my dear friend from a cajun,,abuelito
O.K. read the first post:
Ok, I'm about to purchase a 1991 Chevy Suburban 2WD with the standard SBC 350 motor in it. I would really like to have a 4WD vehicle, but since I'm getting this truck in immaculate condition and at a steal price level, I can't turn it down. I've done a little bit of researched, talked with a few of my buddies who are mechanics, and it looks pretty good that I will probably be able to convert this truck to 4 wheel drive rather painlessly. Of course, however, I want to confirm it with the experts first. :) Since it's a '91, it's still using the old manual-style transfer case, which shouldn't require any wiring. So, it looks like, it's going to be a moderatly simple job of taking the front end apartn, dropping the old driveshaft, putting the front axle in the front with CV shafts, locking hubs (I hope I can' find auto-locking hubs for it?), mounting the transfer case, and putting 2 new driveshafts in. It just seems that it can't be THAT easy to do, I've got to b missing something.. Thanks for any advice anyone can give to me.

The cost will be what's spent on sourcing a trashed Suburban 4x4, the rest would be his labor, if you cant find a trashed 4x4 for under $800 your looking in the wrong place. Addmitedly I'd probably buy a 4x4 in the begining, but that wasnt what he asked, he asked how to convert what he was buying.
If he wants money tell him to try a bank.
 

·
Super Moderator
Joined
·
3,369 Posts
Discussion Starter #20
The end-all would probably be the fact that yes, I have already purchased a burb that is only 2wd. I want a 4wd burb. I do very much love suburbans, and I want to create the "ultimate" burb for me. I am probably not one of the best bargain hunters when it comes to getting sweet deals on new or used items that I am looking for. The deal that I got was basically dumped into my lap, I did not seek the deal. Now, I am working on trying to make what I'd like happen, one way or another. I am looking for a project vehicle that I can make better to increase the enjoyment of the vehicle, and also have a vehicle that works well in disasters (think Katrina). IMO, the biggest thing that is stopping me from doing a SAS is the fact that I feel that I should first find/make a friend who knows more about off-roading and working on off-road vehicles to help me in this project. I am a competent wrench-turner, but I am not the best at knowing "if this is acting like that, the problem is this", but I am very open to learning. I am also to trying to find a 4x4 sub in decent condition for a decent price. As could be thought of most people, I don't want to spend a lot on the job, but I also realize that spending a decent amount of money is crucial to actually complete such a project. In my mind, I have a vision of when the burb will look like in the end, I'm just trying to figure out the "how do I get to my goal" part.
 
1 - 20 of 20 Posts
Top