92 k2500 suburban 7.4L differential noise

[92burb]

There is a whining noise coming from the rear-end and I'm not sure if it's the posi or something else. At slow speed turns from a stop it seems to bind or lock up the rear-end.

 

[ak diesel driver]

Checked the fluid level?

 

[ak diesel driver]

Could also be a sign the gov-lock is giving up

 

[92burb]

Could also be a sign the gov-lock is giving up

Is the gov-lock the posi trac? And no I haven't checked the fluid yet. Low on funds and injures my shoulder working on the transmission

 

[WarWagon]

^^^ Park it till you or buddies can check it out. Rear end locking up is a great way to suddenly depart the roadway and hit the wall…

 

[MrMarty51]

^^^ Park it till you or buddies can check it out. Rear end locking up is a great way to suddenly depart the roadway and hit the wall…

….. /\_/\_/\ WHAT HE SAID /\_/\_/\ …..

 

[92burb]

^^^ Park it till you or buddies can check it out. Rear end locking up is a great way to suddenly depart the roadway and hit the wall…

Where is the filler hole? It's a 14bolt

 

[SnowDrift]

Passenger side of differential casting. 3/8" short extension will plug right into the square hole. Might need to clean it out the hole with a pick or screwdriver to get a good bite.

if you refill, use a synthetic with friction modifiers or get the additive for posi-rear.

Probably a good excuse to pull the cover off and change the oil if it hasn't been done.

 

[MrMarty51]

Yup, plug is a square female drive. Its located rearwards of the input yoke.
Usually has some dirty oily substance around it.

 

[92burb]

Yup, plug is a square female drive. Its located rearwards of the input yoke.
Usually has some dirty oily substance around it.

Thanks for the tips.

 

[MrMarty51]

Thanks for the tips.

I once busted the square drive off on a Snap On 3/8ths drive ratchet handle.
It sheared off right where the detent assembly fits into the square drive lug.
If You are going to use just a ratchet handle or a breaker bar and if that plug is really tight, be sure that the ratchet handle that You use is a cheap one. Harbor fright or some such.
Snap On dealer warrented My ratchet drive but it came with a warning, he would warranty no more for the same reason.
That was when I bought a set of the male square drive adapters. I have not broke another ratchet handle drive lug since then.
Those square drive lug adaptors looks like the square drive of a ratchet handle except there is no detent spring hole through them.

 

[ak diesel driver]

IIRC the gov-lok doesn't use and posi additives

 

[dbrannon79]

Correct. the factory gov-lock uses no additives. just run full synthetic 75w90 oil.

when you say it tries to lock at slow speeds, are you saying both rear tires try locking up or is it when you make a turn one wheel tries skipping as if it's locked wheel to wheel.

On the Gov-lock units there is a small weighted lever that is supposed to lock the spider gear assy at low speeds if it seems one wheel looses traction. it's a fully mechanical setup. there are also some clutches in there to allow some slip for when turning a corner, but those clutches can be worn out. also the weighted lever also has a spring on it that can get broken too causing it to attempt to lock up at higher speeds.

best thing to do is pull the rear cover off and drain the fluid. clean out the pumpkin while looking for any pieces, chunks, or lots of metalic glitter. if it all looks OK, then put it all together and fill with clean synthetic fluid.

while you have it apart, you should be able to see the lever on the third member housing where the spider gears are at. make sure it's not broken or warn.

Here are a couple of youtube videos explaining it better than I can.

 

[dbrannon79]

Just don't go modifying or welding on yours. guaranteed Gov-Bomb if you do!

 

[MrMarty51]

Also, a posi track type rear differential will get a vehicle totally sideways in a quick hurry.
I know of many mighty cool cars that were sideways and got against other vehicles, fences, utility poles and etc.
Not counting the ones that rolled over after they went to the ditch.