99 Front Differential

[BOTTLEFEDCUTLASS]

Anyone have any idea how hard it is to remove the front differential? I'm getting a howling sound when I have the 4-wheel engaged. I have checked all the fluids and they all seem full except the front differential. The gear lube looks a little on the shinny side. I have removed the front drive shaft when I had it in the air to see if it would go away and it did. So I thinking I have to remove the differential to see what is going on inside. Any ideas what I might find?

[internic]

never personally done it but i think all you have to do is remove the front drive shaft and the two cv shafts, disconnect the shift-on-the-fly wiring if you have it, and then its just some very large bolts holding it to the frame. also, remove skid plates before doing any of the former.

[mjgjr72]

not that hard
jack up and secure front end
remove skid plate
disconnect front proppeller shaft
r+r tires
disconnect both front cv axles from ft diff flanges
disconnect breather tube on drivers side of diff case
disconnect actuator connector and remove wires from plastic clips on diff housing i think there are 4 black clips
support diff housing
remove diff mount bolt on drivers top and bottom of housing
remove two nuts from diff mount on passangers side of housing
lower housing slightly and push towards passsenger side
turn housing so yoke moves up and lower drivers side down and slide housing out

your done

if you plan on rebuilding diff yourself there are specialty tools needed for reassembly and setup of gears

[BOTTLEFEDCUTLASS]

I'm having a problem finding a book on the inside or guts of the differential. Any ideas were I can find this info?

[mjgjr72]

dealer manual is the only place i have seen it, but u can go and thumb through a manual at an auto store and see if they have a decent section for it

[ronnier38930]

What is the average cost to get the front differential rebuilt? I have replaced everything from front drive shaft, Yolk, and U-joints, and added oil but I still have a vibration from 45+ miles an hour.

Thanks

Originally Posted by internic

never personally done it but i think all you have to do is remove the front drive shaft and the two cv shafts, disconnect the shift-on-the-fly wiring if you have it, and then its just some very large bolts holding it to the frame. also, remove skid plates before doing any of the former.

[[email protected]]

Originally Posted by ronnier38930

What is the average cost to get the front differential rebuilt? I have replaced everything from front drive shaft, Yolk, and U-joints, and added oil but I still have a vibration from 45+ miles an hour.

Thanks

Have you checked the tires are one of the joints

[LongIslander26]

Originally Posted by BOTTLEFEDCUTLASS

Anyone have any idea how hard it is to remove the front differential? I'm getting a howling sound when I have the 4-wheel engaged. I have checked all the fluids and they all seem full except the front differential. The gear lube looks a little on the shinny side. I have removed the front drive shaft when I had it in the air to see if it would go away and it did. So I thinking I have to remove the differential to see what is going on inside. Any ideas what I might find?

Chevrolet has a TSB concerning this problem. I don't remeber exactly what it said, but they know what is causing it. I'll look into it and see what I can find.

[LongIslander26]

Here is what I found on another site I go to. It's in quotes because I copied and pasted it right from there. The authors of these quotes are GM master techs currently working at dealerships who see this all the time.

"there has been a problem with the front differentials, we have had a rash of them bind up, usually the carrier bearings go bad, in some cases it also burns up the clutches in the transfer case, the easiest way to find this out is to drop the front drive shaft and see if you can easily turn the front pinion yoke, if it is hard, then your front diff. is locked up and will need to be disassembled and redone, and from what i've seen this condition is usually noticed in 4wd mode"

"There have been many problems with the front pinion bearing galling and pitting causing humming. Just about every new 4x4 has this problem for some reason."

I have not seen this particular problem myself personally, so I have no experience at repairing this. Differentials generally aren't something you can just "Take apart and put back together", so if your experience in mechanics is limited, you may want to have it done. You may also want to pay a dealership a visit, and maybe talk to one of the parts guys or a tech to see if Chevrolet has come up with a fix for this problem, or re-engineered parts. No sense in putting new parts in it that caused the problem in the first place. Hope this helps.

[wagslick]

I also, need to replace the front differential on my 99 Silverado.... I think. (Let me know if I'm way off).

4wd is not working but the 4wd light is NOT on and I took the truck to autozone and they mentioned no 4wd related codes. I originally thought the problem was with the encoder motor and took that in for repair. Mechanic said the encoder motor works fine, however the front axle is very difficult to turn. When I try to engage 4wd, everything seems to work fine but the front wheels do not pull.

How can I be sure my 4wd problem is with the differential and not the actuator motor on the front differential?

[MT-2500]

Originally Posted by wagslick

I also, need to replace the front differential on my 99 Silverado.... I think. (Let me know if I'm way off).

4wd is not working but the 4wd light is NOT on and I took the truck to autozone and they mentioned no 4wd related codes. I originally thought the problem was with the encoder motor and took that in for repair. Mechanic said the encoder motor works fine, however the front axle is very difficult to turn. When I try to engage 4wd, everything seems to work fine but the front wheels do not pull.

How can I be sure my 4wd problem is with the differential and not the actuator motor on the front differential?

Best to start a New Thread on you problem.

AZ is not much on 4W codes.
Did they use a transfer case/transmission capable scanner or just the OBD11 code job?

Old type 2 wire actuator?
What transfer case?

The actuator has to have good 12 volts and ground when you hit 4W for it to kick in.
Does it have voltage and ground?

Have you checked fuse for 4W?
Any shift button ligt lighting up when you press 4W
Is front drive shaft locking in?

[j cAT]

Originally Posted by wagslick

I also, need to replace the front differential on my 99 Silverado.... I think. (Let me know if I'm way off).

4wd is not working but the 4wd light is NOT on and I took the truck to autozone and they mentioned no 4wd related codes. I originally thought the problem was with the encoder motor and took that in for repair. Mechanic said the encoder motor works fine, however the front axle is very difficult to turn. When I try to engage 4wd, everything seems to work fine but the front wheels do not pull.

How can I be sure my 4wd problem is with the differential and not the actuator motor on the front differential?

the encoder motor engages the front axles to the rear axles..that is it ! so how can this "MECHANIC" STATE THE ENCODER IS WORKING ...

the drive train codes need to be pulled. also check the fuses..

this will require a oem drivetrain code scanner ..a transmission repair shop should have one..I would not go back to the last guy you saw.

the front diff has a locking actuator this locks the left axle to the right axle . now you have a solid axle in the front when in any 4wd position ..so jack up the vehicle in auto 4wd.. lift one wheel off ground is it locked ? if so then we get into the transfercase..

check fluid in transfercase is it black if so a very good chance the clutches are gone, drain the transfercase fluid any metal particles/chunks? also fluid is blue in color..need 3 qts of trac II fluid..

post back with your results, have the dtc failure code also .