Need advice on what to do with a donor burb

[tvonloss]

I just came across for free a 89 suburban 3/4 ton truck that has a blowd up motor. Anyway want to grab as much off it as I can use before we send it out to pasture. I have a 90 Blazer w/35's, 10 bolts w/4.88 gears, 700r trans/241 TC. The Burban has a 10 bolt up front, th400, np241c transfer case and a semi-floating 14 bolt out back 9 1/2" and open carrier.

First I want the rear but wonder what is the most reasonably economical way to have a solid locker back there and I'll need to regear of course.

Second as I'll be needing to convert to 8 lug up front and my axle is already regeared and has all new ball joints and brakes, what will I have to change to convert to the 8 lug? I know the rotors have to go but will I have to swap knuckles also,are the calipers the same? Or do I need to swap the whole axle?

I'm just trying to figure out what I'm getting into beforehand so I don't have huge downtime. Thanks!!

O yea what about the transfer case worth saving?I know the trans is but will they have to be used together or will I be able to replace my TC when it breaks with this one? If not I'll sell em both..

 

[dremu]

The popular wisdom is that a 14b semi-floater may not be worth the hassle in your case. I for one wouldn't drop $$ on regearing one ... I'd get a full-float and be done with it. Others say they're worthwhile. I don't know what the locker options are for the SF; I know for the FF there's the Gov-Loc, the ARB, and the most popular here, the Detroit.

The front axles on these two trucks are basically identical to the knuckles. There MAY be an issue with axle splines; early 10bolts have 28 splines and the later ones are 30, and I don't remember what the cut off is.) Count them on both trucks, and if they're the same, snag the Burb's as spares for your truck. Handy things to have, the price is right, and since you're taking the front axle down anyway, you'll be in there...

The knuckles are the same, and given that you've already regeared your existing front, it does NOT make sense to switch. (I switched axles, for instance, when I did mine, as the new axle had 4.10:1's and the old 3.73:1's ... that's a no-brainer )

Switching to 8-lug is easy.

http://coloradok5.com/8lugconversion.shtml

I would grab everything from the spindles out, including the calipers. That's the spindle and related bearings, backing plate, caliper, rotor, and hub. The 1/2 ton calipers are the same size / mounting as the 3/4's, but have a smaller piston. If you've just recently put new calipers on the 1/2 and the 3/4's are scuzzy looking, you COULD try the 1/2's on the 8-lug. Pretty sure they'll fit, though I donno whether you'll like the braking.

The xfer case I'm not entirely sure about (too new for me! ); the two trannies may have different adapters to the same xfer case, so if you're gonna keep it, also save the adapter(s) between them. (I'd hang onto the t-case as they do break, and you'll kick yourself in six months if you have to go buy another one =)) If the adapters are different, you can prolly sell the TH400 one you won't need, either here or on Ebay.

Speaking of selling stuff, if you have the time, the TBI setup on the Burb is prolly worth a bit of change. (Small sales pitch: A paid membership here is a great investment! )

You should also measure the front driveshaft on the Burb; it depends on the length of the two trannies and their adapters, but it's likely close to if not the same as your Blazer's, and that means you have a spare.

Other than that, check all the little stuff on the new truck and if still good, hang onto them as trail spares (like the axle shafts above, or the steering stabilizer as those get bashed in and leak, etc etc.)

Heck, the Burb prolly has 56" springs in back, so I'd keep those, and someday put your existing rear 52"s in the front (unless they're crazy lifted) and then these 56"s in the back of your Blazer.

Also depends on how much storage space you have and what your future plans for your Blazer are ... if you're ever thinking Doubler, keep the tranny/xfer case crossmember and any skid plates the Burb has.

The 88-91 front clips are also popular with folks with the older trucks, and if in good condition with all the headlights and wiring can net you a c-note or two fairly easily. And if the Burb has barn doors they can sell too.

When you're done you may not have much left of the Burb but a tub and some glass =))

-- A

 

[tvonloss]

Thanks for your time and the good info. From what I've read both trucks (89-91) will have the 30 spline axles up front. As far as the Semi-floater out back parts are more expensive but I was just looking for a good upgrade but I think I could probably find one with better parts to start with in this case and save money in the end. I would rather the full floater, they're just nicer to work on.

I just checked it does have the 56" springs out back which is cool cause I was about to do a shackle flip on mine so they're going on at the same time. I am in no hurry to have it the way I want it but want to be able to use it in the meantime. I can come up with parts get them ready and do the work in chunks. It normally works out way cheaper when your not in a hurry.

Here's what I got so far.

 

[muddermilitia]

The 89 np-241 will be a mechanical speedo. Your 90 has an electronic speedo. Also the 241 in your blazer will have a 27-spline input while the 241 in the burb will have a 32-spline. That np-241 would probably be worth something to a guy with a M1008 that wants to get rid of his np-208. It would be a direct swap into a M1008.

 

[tvonloss]

Thanks. I didn't think it would interchange but couldn't remember what the tailshaft of a 700R looked like on a 4x4.