Chevy & GMC Vans

there's always Smith Rocks... bust of luck.

Man, I woke up in the middle of the night and remembered something I forgot to tell you.

The Driveshaft (pinion) inputs aren't all the same! Some will have a round flange others will have a u-joint yoke. Ideally you would get one that corresponds to your original. If you can't, no biggy as they are interchangeable. However, if you need to swap the flange/yoke out, you will need a big socket, an impact wrench and/or some ingenuity to get the pinion nut off.

Also, when tightening the pinion it is somewhat critical not to get it to tight (or to loose) as this nut pre-loads the pinion bearings. It is wise to install a new nut as they are designed to be self looking/one time use (I use lock-tite on mine as well). If you don't feel comfortable with this, take it into a drivetrain shop, they should switch it out for very little $$$.

Yea, thanks for the tip. I'm aware of the u-joint style as I removed a tranny from a suburban with just that.

I plan to get there bright and early tomorrow with the goal of doing the swap on their parking lot (if they'll let me). In any case, IF I get a Blazer front drive assembly I'll definitely get the one with the flange and hopefully that's the only thing to look out for!

I also called a chevy dealership to confirm the gear ratio.

Not looking good. I don't think they have either the Astro or blazer part. I may be stuck with 2wd. Extra suck in that they don't give refunds so I'm out the cost of the tcase. Wheee!

Maybe it's due to my stubbornness, but I nearly have this thing fixed. I found a front diff from a different parts place and in the middle of the swap.

I got frustrated trying to figure out how to remove the original diff. All the bolts are out, but it's resting on the steering linkage up front and the bottom mount in the rear. There appears to be some kind of lift and twist necessary? The service manual says:

A: Slide assembly to the right. (who's right? Passenger-side?)
B: Drop the tube end and twist the carrier to clear the mounting brackets, oil pan, and steering linkage. (twist which way? Twist the tube towards the front/rear? Twist clockwise? wtf?)

Taking a breather while I nurse my wound (melon-balled my distal knuckle trying to remove the lid on the gear oil tub). I use that knuckle to jam cracks dammit!

ball wrote: (melon-balled my distal knuckle trying to remove the lid on the gear oil tub). I use that knuckle to jam cracks dammit!

Shoulda taped up! Two bolts on the drivers side, drop the idler arm. Made the job easy for me (I had both idler arms off at the time, but I bet one side will do it.

WHEW! Oh man, got all the parts on and tight now. I feel and look like I've been wrestling a walrus in a 50gal barrel full of axle grease! Getting that diff installed required some serious core strength. I also had to swap one of the bushings which was a barrel of fun without the special tool. Thankfully there is a press here and I found three scrap pieces of steel tubing which were the exact sizes I needed.

The beta that worked for me was to point the tube down and forward then shove the diff in high while the steering was turned all the way left.

No highway speeds yet, but I'm glad just to be out of there.

I did notice that if I pulled both tires inward (as though to create toe-in), the steering linkage lifted as though the idler arm bushing was loose? The idler arm pivoted upward. I don't notice the looseness when the vehicle is down and I'm steering.

Anyway, time for liquid refreshment! (after which I'll try to rally to change the rear gear oil)

well done, hope the beer was good! Here's how Moog suggests checking idlers; http://aftermarket.federalmogul.com/en- ... %20Arm.pdf

I love how I'd have to dig a 6' hole in order to inspect it them GM way

So everything appears to work and it no longer creeps which brings me to one last question before I put this thread to bed:

Why did the creep go away? I thought the connection from the tail shaft to the rear (t-case) was solid and only the front drive was viscous. I've been driving with a completely absent front drive for 1500 miles.

The tail shaft is not directly coupled on this particular transfer case. The exploded view shows this. This is not the only transfer case that has this type of setup. The resistance of the viscous connected to the front shaft, front differential and front wheels is needed to keep from creeping. It is well known that if you remove your front drive shaft with this TC you will find your vehicle at the bottom of a hill while in park with a weak ebrake.

My research on this has led me to believe this coupling problem was "one" of the reasons these were phased out starting in the mid 90's. It is one of the things that will keep me from buying a 1998 and earlier van. Don't get me wrong, these TC are very reliable, they are just not were I need them to be.

After reading thru this entire thread, I believe my Transfer case must be completely toast.

Heres why: I thought I would be able to drive the 1990 van with only 1 driveshaft....
So, I removed the front driveshaft.
Started up the engine, put in any gear the van will not move, engine just revs away.
Re-installed the front driveshaft but then removed the rear driveshaft.
Started up the engine, put in any gear the van will not move, engine just revs away.
Put BOTH driveshafts back in and the van drives, doesn't creep in park etc.
IS THIS RIGHT?