Rear End Axle Problem......

Jay-Bird · Post by **Jay-Bird** » Sun Mar 02, 2003 5:21 pm

I have a 2002 GMC Crew Cab Sonoma and when you take off from a stop when turning it has like a small shudder in the rear axle. And can I join the web site

P.S.

hossjr3@yahoo.com

Post by **HenryJ** » Sun Mar 02, 2003 6:06 pm

Jay-Bird wrote:I have a 2002 GMC Crew Cab Sonoma and when you take off from a stop when turning it has like a small shudder in the rear axle. And can I join the web site

Off the top of my head , you may be feeling the G-80 diff. being a little difficult (sticky).

We have a centrifical locker, the fly weight locks the axles during normal operation. Yours may be staying locked causing the scrubbing feeling when you make a sharp turn from a stop.

Did you change the gear lube at the first oil change as listed in the owners manual?

If not it is past time to change it.

Mine became noticably smoother after the service was done.

As for the website: email Hobie (a2b) with the information. He'll be glad to see someone from his stomp'n grounds join

seapahn · Post by **seapahn** » Sun Mar 02, 2003 6:13 pm

Yup ... as HenryJ said, sounds a lot like "normal operation" of the G80 locker. Did yours come with the locking rear differential option? If NOT, then you got a problem. But if yes, then it's probably normal.

Conman · Post by **Conman** » Sun Mar 02, 2003 6:20 pm

I have my rear end fluid changed at 3k and it def. got smoother. They did add the additive(well, they charged me atleast). It's recommended in the owners manual to replace the fluid at 3k. Check your glove box and see if you have the Code G80. If this is not the case, I'm wondering if you have a bad case of axle wrap(axle hop). Maybe you have a bad shock cause your rear to hop more. Just guessing.

Cheers,

Con

quickbiker · Post by **quickbiker** » Sun Mar 02, 2003 7:07 pm

I see you are finding your way Jay!

Rusty · Post by **Rusty** » Mon Mar 03, 2003 6:26 pm

HenryJ wrote:Did you change the gear lube at the first oil change as listed in the owners manual?

If not it is past time to change it.

Uh, I was supposed to change the rear lube at my first oil change? Whoops!

Post by **HenryJ** » Mon Mar 03, 2003 6:33 pm

You mean that you did not read the owners manual, cover-to-cover, before operating your new vehicle

Here is the thread: Locking rear (G80)

seapahn · Post by **seapahn** » Mon Mar 03, 2003 10:28 pm

GaryH wrote:
HenryJ wrote:Did you change the gear lube at the first oil change as listed in the owners manual?

If not it is past time to change it.

Uh, I was supposed to change the rear lube at my first oil change? Whoops!

Only if you have the G80 (locking diff) ... it's not a big deal if you ask me but if you plan to keep the truck for a while, it's not a bad idea.

But I was almost certain I read somewhere about NO additives or friction modifiers but I could be wrong. I just went with the regular fluid GM recommends for the rear.

Rusty · Post by **Rusty** » Tue Mar 04, 2003 3:57 am

Actually, I did take it to the dealer for it's 5k mile (or whatever it's called) service. They may have done it then. I don't know. I'm at 25k now and am planning to change it again anyhow along with tranny. I will admit though that right now I don't have a clue where my owners manual is! It's somewhere in that black hole in space I call my garage.

Doogy · Post by **Doogy** » Tue Mar 04, 2003 9:44 am

What type of additive or synthetic would anyone recommend

I saw a program on TNN where they used Royal Purple and ran a vehicle on the Dyno after swapping it in the diff and other driveline components and it actually added more HP at the rear wheels. Is the stuff any good???

quickbiker · Post by **quickbiker** » Tue Mar 04, 2003 7:49 pm

Just my opinion, but from my experience, additives are a huge waste of money. Just use what is designed for it, and change at recommended intervals, and you'll have no problem. I've tried it all, synthetic, slick 50, STP, blablabla. It's all garbage. And the thing about changing your motor oil every 3k miles is all hogwash too. I change about every 6.5k - 7k miles, no problem, and use the cheapest oil I can find. Hey, it's slippery.

I've done that with my Dodge dakota, and run it to 150k miles and it ran like new. I just got rid of it, cause I really was rough with it, and the body was smashed and reshaped to many times, LOL. Plus I wanted a 4 door truck.

malkavian · Post by **malkavian** » Thu Sep 16, 2004 12:07 am

hmmm changing the diff fluid at 3k didnt know that one. I read the manual must have missed it. I have the same noise with mine starting from a dead stop makeing a tight turn. Ill be doing the change this weekend though.

Post by **HenryJ** » Thu Sep 16, 2004 4:58 am

malkavian wrote:hmmm changing the diff fluid at 3k didnt know that one.... must have missed it...

It is on page 7-8 in my 2001 owners manual, next to the second bullet.
Welcome

glad you found us!

coffeedrnkr · Post by **coffeedrnkr** » Tue Sep 21, 2004 6:48 am

The limited slip additive really does work though.

My grandpa took his f150 back to ford to get all his fluids changed and when he got it back his rear end grinded and howled every time he turned a corner. He took it back and it turned out to be that they didn't add the limited slip stuff and his clutch packs were grinding in the limited. when he took it back they added the stuff and now it works perfectly.

malkavian · Post by **malkavian** » Tue Sep 21, 2004 8:28 am

changed mine last weekend and added the additive. mine dosnt do it any more.

Post by **HenryJ** » Tue Sep 21, 2004 9:46 am

coffeedrnkr wrote:The limited slip additive really does work though.

You know that the Eaton gov-lock that we have does not use friction modifiers/additives , right?

Socaldave · Post by **Socaldave** » Tue Sep 21, 2004 2:12 pm

Correct HenryJ! Do not use additives with our Eaton G80 locker...........

coffeedrnkr · Post by **coffeedrnkr** » Tue Sep 21, 2004 3:03 pm

I did not know that, never had the stock one. I have a heavy duty torsen and my doesn't need any.

malkavian · Post by **malkavian** » Tue Sep 21, 2004 9:35 pm

what the? why did they sale it to me at the dealership? crud... Do I need to change it again to get that additive out?

Post by **HenryJ** » Wed Sep 22, 2004 4:27 am

malkavian wrote:what the? why did they sale it to me at the dealership? crud... Do I need to change it again to get that additive out?

How long has it been since the dealership added it?

If it has not been too long, I'd find the recommended lubricant chart in your owners manual , show it to them and ask that they remedy the situation.

If it has been a while, I'd "bite the bullet" and change ity myself. It is not that expensive, and maybe it is time to add that differential stiffening rear cover now anyhow

malkavian · Post by **malkavian** » Thu Sep 23, 2004 7:26 am

I did it myself. I just went to the parts counter at the dealership and told the guy what I had and I needed lube and gasket for the rear end. He gave me the lube, additive, and gasket. I went home and changed it. It was in there a week. I got more lube and another gasket and changed it Tuesday night. Theres another thread I just read on here that ours has a limited slip??? Im going to do a little research and find out exactly what the rear diff is.

Maybe its a piece of a warp drive.

Ken · Post by **Ken** » Thu Sep 23, 2004 3:31 pm

Doogy wrote:What type of additive or synthetic would anyone recommend I saw a program on TNN where they used Royal Purple and ran a vehicle on the Dyno after swapping it in the diff and other driveline components and it actually added more HP at the rear wheels. Is the stuff any good???

First of all stay away from additives. I don't care if it's for engine oil, diffs, or transmissions just stay away from that stuff. Oil companies spend Millions of dollars in R&D to perfect the chemistry of a fluid and when you add an additive you cant help but upset/disrupt that chemistry.

If you want to use Synthetics, (and who wouldn't) make sure you understand the difference between them. Understand that a "Group III" Synthetic is a Petroleum based product and a "Group IV" is a true synthetic. Group IV oils are PAO (polyalphaolefins) base stock. This means 100% man made and not dinosaur juice. However due to a lawsuit by Mobil oil companies can use a Gruop III oil and legally label it "100%" synthetic (Again group III is petroleum). This simply defies the definition of "Synthetic". It gets even better, an oil company can take a "Group II" (lets say a .99 cent quart of Penzoil) add 5-10% worth of a Group III, and they can sell that to you as a "Synthetic Blend" and charge you $2.50 + for that "Blend". Also be aware there is a large difference in the quality of Group IV oil, they are not all the same different companies use different formulations/quality base stocks.