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Oil Change And Posi-traction Service?

gotchange:

The hum occurs when accelerating and to a lesser degree and just barely audible, on deceleration. Again, only noticeable in the speed range of about 45 to 60 mph. It's almost as if below 45 is too slow and above 60 is too high a pitch. Yes, the pitch of the hum changes from a lower sounding hum at 45 mph to a higher sound hum to 60 mph.

Thanks, Ron
 
gotchange:

I also get the hum just holding speed. I'm not sure if that's what you meant by coasting.
Ron
 
next dealer visit, mention backlash, or r&p shimming, new truck should not howl,, not your tires right?
 
Just FYI. ?I changed my oil today (960 miles on AV). ?The oil was a little darker than I would have liked to see it. ?My old experience told me to change it at 500 miles on a new vehicle (still a good practice IMO) but just didn't get to it. ?IMO if I had let the computer tell me, probally somewhere after 3000 miles, it would have been way too long for this first oil change. ?

Point is check your oil and use good judgement (experience) on what the oil looks like (this is not an all encompassing quality check of the oil...but a darn good and EASY one). ?And yes I did use syn oil...have for over 10 years...even in my lawn mower!

And BTW...
positrac...100% locked 100% of the time...good for straight line racing and SOME off road application

limited slip...just that...limits the amount of slip/wheel spin in relation to other wheel...good all round driving and off road (except mud...IMO)

Limited slip locking...will lock the wheels after a certain amount of slip (torque related also) like positrac...ideally! ?great for general road driving and when you get stuck in the mud.


Anyone remember how we used to put on the parking brake some to get unstuck from the mud? ;)
 
LexLuthor said:
And BTW...
positrac...100% locked 100% of the time...good for straight line racing and SOME off road application

limited slip...just that...limits the amount of slip/wheel spin in relation to other wheel...good all round driving and off road (except mud...IMO)

Limited slip locking...will lock the wheels after a certain amount of slip (torque related also) like positrac...ideally! ?great for general road driving and when you get stuck in the mud.


Anyone remember how we used to put on the parking brake some to get unstuck from the mud? ;)
Oh, well allow me to retort! ;D
Positraction is not 100% locked, 100% of the time. That is what is called a "spool". Positraction is a limited slip diff. Here is an excellent webite that will clear up much of confusion regarding differentials.
Ring & Pinion
 
steelhead chaser,, ever caught a bonefish??? thats the sly devil in these parts, but yep send em to the info web site posi is chevs old name for limited slip... dayamn in senior high school, my "'spool" eas done by the welder in shop class, we welded the spiders all together, nothing would come off a light like my 57 with welded up 4-56s one day one the way to school, i nailed it in second in the rain, theright tire was on dry the left on wet street , and the 57 got totaled out on a big tree. the headlights touched each other!!! still got the scars, and the memories
 
got_change:

I'm sure it's not the tires. I'll be visiting the dealership tomorrow and will mention backlash and r/p shimming. Thanks for the input.
 
got_change:

I'm sure it's not the tires. I'll be visiting the dealership tomorrow and will mention backlash and r/p shimming. Thanks for the input.

Ron
 
hey, ron, if they say they never had a problem before like yours, get them to take a ride and hear it themselves and be sure its recorede on the work order write up!
 
ROGERH,,,,,went to the trouble to post a link to Eaton [g80] differentials.......That is what we have in the Avalanche. Just go and read the link and print it and put in in you owners manual for further use........ken
 
Thanks to the thread, I now know a lot more about my rear differential, G-80 Eaton, and how it works. This leads me to the question of how does the front work in 4WD. Is there a front differential? The transfer case sends the power to the front but I am assuming that there must be a front differential to send the power to the front wheels. Is it limited slip, locking or open (standard)? Also are there any special care or oil additives needed? ???
 
got_change:

Took it in Wednesday and they replaced the following:

Gear Set - Bearing - Brg. ASM-R - Bearing - Seal - Gasket - Bearing - Spacer - Gear Lubr.

The work order indicates the ring and pinion in rear differential was replaced. They also noted an added operation - axle concern - whatever that is. Time for this job is 4.90 hours. I got my hands on a shop manual and checked out the procedures for this repair. Quite a complicated operation. Apparently the mechanic knew what he was doing. Everything is ok. What really impressed me was that the shop foreman called me early in the a.m. right after he had talked to GM to let me know that they would replace the ring and pinion. He had an opening that day and I brought it right in. Then in the afternoon I received another call telling me the job was complete and I could pick it up at my convenience. I, like many others, usually dread going to the dealer. This was a pleasant surprise. Job done right the first time and the phone calls. Perhaps I'll buy by next vehicle from them.

Today I had a muffler put on. Will post about it in the Performance section.

Thanks for you help. Ron
 
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