Chevy & GMC Vans

So I installed my front diff yesterday and replaces all fluids with dextron 6 took it for a test drive yesterday and it ran fine no problems tried to drive to work today and all of a sudden there was a high pitch sound it sounds like its coming from the back and also the car starts to wobble real bad. also it starts pulling hard right. When I drive slow and turn left its got a jerky feel in the steering wheel.

Also the rear end was just replaced by a mechanic

Thanks

With the recent rear end replacement, were you able to drive it before the front end diff work i.e. without a wobble?

Yes I drove it 200miles back home

Make sure all your lug nuts are tight and if you have steel wheels, one isn't cracked.

OK so I can not believe what I found when I got underneath the van to double check if I didn't miss something when putting in the front diff.

Well after I checked over my work I found out I did everything right, so I figured wtf let me look over the back too where the mechanic put in the rear end, and what do I find. On the passenger side the u-shaped thing that holds together the leaf springs was complete bend in to oblivion and broken just hanging there in a awkward position and one of the leaf springs was completely flying around.

Haven't had a chance to go and get a new one, but I am pretty sure thats what was causing my wobbling and weird noises from the back hehe.

I just hope nothing else got damaged.

Man... i would like to see some pics of that if you can get some.

Ok so unfortunatly that wasnt causing my problems.

Now Im wondering if the front diff from the 93 all wheel drive I got is the wrong gear ration.

I have a 3:42 in the rear. where do I find the diff part# to check which one it is for the front, and does anyone know what ratios 93's came in.

What would the effects be on the car if the front and rear had differ ratios?

Cause right now it seems like once everything warms up I start getting weird whining noises and the car starts like wobbling I guess kinda feels like the wheels wanna go different directions.

Upon further inspection, I have a feeling that the viscous coupling in my t-case has seized up is causing my problems. I think whats happening is since the viscous coupling sized up its transferring full power between the front and rear wheels none stop even on dry ground, causing my van to become unstable since all four wheels are trying to fight each other.

This would also make sense because these problems don't seem to occur until the van warms up and goes into higher speeds and from what I have learned the viscous coupling works on the basis of the fluid heating up and helping it transfer power to the front and back.

Any thoughts or ideas on this?

From what I understand a locked up viscous clutch would be like driving a 4x4 with the transfer case engaged. You should be able to tell doing figure 8s in a parking lot. The rear will have a shorter distance to go and will try to push the front end, causing the front wheels to slip towards the outside of the turn.

Once you verify that the gear ratios are the same front/rear and you are still suspecting the TC, try pulling the front drive shaft. The van should then drive like a normal 2WD van.

seems to simple, but i would imagine after changing the front dif you could use an alignment. did you look into that at all? like i said probably too simple to be the case, but i know i over think things sometimes and overlook the basics...

Well, Im going to pick up the t-case from the same 93 I got my front diff from. The guy there is cutting me an awesome deal and its a quick job so why not.

Im actually tempted to get the rear end from that car too and then do a complete swap over since that van had 20k less miles then mine anyways hehe.

I also noticed that my rear right wheel is a 205 and not a 215 like the rest, but i doubt that would make such significant difference with the problem Im having hehe.

sxfx wrote:
I also noticed that my rear right wheel is a 205 and not a 215 like the rest, but i doubt that would make such significant difference with the problem Im having hehe.

Actually, that could be what caused all of the problems in the first place. The tires must match exactly.

The usual order of destruction is the case seizes, and then the front dif grenades. It is common to find the front dif ruined and replace it only to have the seized case ruin the new one.

sxfx wrote:I also noticed that my rear right wheel is a 205 and not a 215 like the rest

Bad, bad, bad, bad.....

Ok so if I only drove like 15 miles testing the new diff in front with the wrong rear right wheel, do you think I could have caused something to break again?

I mean I didn't beat on it or anything just couple straight away to maybe 40 max, and couple figure 8's here and there.

I'm going to be replacing the tire and T-Case on Saturday hopefully I didn't break the rear diff or front diff again.

And I just noticed the tire difference last night too. Im just glad my front diff was blown before I drove it 200 miles home.

sxfx, Lets establish some facts here.
You've got a broken spring mount on a recently replaced/repaired rear end. You drove it for 200 hundred miles with a 205 tire on one side and a 215 on the other. You replaced the front differential assembly without knowing the gear ratio. Then you drove it for what you say was only about 15 miles. Now you're getting ready to replace the transfer case. Do I have it right so far?
Man slow down and get some of the basics right first. Get 2 of the same size/brand tires on the back. Fix the mount on the rear end. Pull your front drive shaft. Figure out what the rear end & front end ratios are. Then figure out what you want to do to fix it right.

Just my TWO CENTS. Jim