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Oil Change And Posi-traction Service?

KurtZ66

KurtZ66

SM 2007
Full Member
Joined
Jun 3, 2002
Messages
84
Location
Atlanta, GA
I need some advice, please.
Yesterday, driving home, the change oil light comes on in my Av for the first time (about 5K miles). No problem, I'll take it in for its first oil change.
The dealership gave me a Recommended Maintenance guide that lists the first service at 3000 miles and includes Oil change, filter and lube, visual inspection and "Posi-Traction Service (optional equipment)", adding that this will add $66 to the oil change price.
Call the dealership and they say:
1) Don't listen to the oil change computer, stick to 3 mos./3000 miles for oil changes. :cautious:
2) Posi-traction is needed at first service and every 10K or 30K depending on who you listen to, and it costs $125.00!!! :7:
What gives? Anyone had this done. I searched the site and didn't find anything and the owner's manual doesn't mention it. Also looked at the GM Service link someone provided, but didn't find anything.
???
BTW-Owner's manual says change oil according to on- board computer.

Any input is appreciated.
 
That dealer is blowing smoke up your rear. He's just trying to generate money for his business. Find you another dealer or service department.
I changed my differential lube at around 1000 miles. I used Amsoil 75W-90. I have the G80 option which is the Eaton locking rearend. I never had any problems with it.
I would go by the oil life monitoring system. That's what its for. If you are worried about the mileage being to long, go to synthetic oil and filter. Synthetics last longer than regular oils. Hope this helps.
 
I guess everyone has their own idea when it comes to service times and such. I always stick to the 3 months /or 3000 miles. Once I go to synthetic,I may up that to 5000 miles but no longer than that for me. As far as the rear end service, I have always in the past done the service between 20-30k miles depending how much towing and off-roading has been done. The tranny is regularly done at 50k for myself,but like I said before,everyone has their own idea and go with what works for you. :B:
 
This has likely been covered over and over, but I thought/heard that our trucks had synthetics in the differentials from the General.
Am I living in fantasyland?
 
victory_red said:
I guess everyone has their own idea when it comes to service times and such. I always stick to the 3 months /or 3000 miles. Once I go to synthetic,I may up that to 5000 miles but no longer than that for me. As far as the rear end service, I have always in the past done the service between 20-30k miles depending how much towing and off-roading has been done. The tranny is regularly done at 50k for myself,but like I said before,everyone has their own idea and go with what works for you. ?:B:
Click to expand...


The computer in the Av only makes a "prediction" on when to change your oil based on your driving habits, not on whether or not the oil is dirty...that being said, I agree with Victory Red...go by your gut and not the fantasy of the long oil change interval...just my .02... :B: (y) ;)
 
Just change the oil,our Avalanches dont require a posi traction service because they dont have a posi traction rear differential. The locking rear differential requires no special service. Follow the owners manual,change the axle fluid often if you do alot of towingor heavy duty driving.

 
hey kcole683,the Av is available with the limited slip rear end and does require service. You can buy the limited slip additive from your dealer's parts counter and IS recomended everytime you change your rear end fluid. Not all AV's have the limited slip rear but I know mine does.
And olsontru,yes supposedly Gm does use synthetics in the differentials.
 
Hey ?VICTORY_red ..... my Z71 has a locking rear end , ?I dont think the AV is available with a posi traction. ?I may be wrong but my owners manual has no mention of a posi traction. ?I had a posi traction in my IMPALA SS and it does require special service. ?The only service required on the AVALANCHE rear end is a gear lube check and top off. ?I did this today @7438 Miles. Front axle was OK,rear was a little low....no signs of leaks .
 
MurmanZ71 said:
ALCON,

I emailed EATON WRT option code G80 maintenance requirements. ?Will post results.

Aloha,
Murman :cool:
Click to expand...
Posi traction and limited slip are the same thing. The Eaton G80 rear diff in the Z71 is a "posi-traction".
Here is a link to the Eaton website.
 
Well I looked at the Eaton website and read that there is a difference in the G80 locking differential and the posi traction....I thought they worked on different operating principals....The point is the locking diff.does not need a special service at 7500 miles other than fluid top off and does not require a special additive.
 
Thank you Steelheadchaser for making that point clear! Limited Slip,locking rear end,posi-trac, and trac-lock are all common terms used to describe the same thing. :B: :B: :B: :B:
 
kurt z66 the eaton web site had a cool av with painted clad, and the sure did have a tire up in the air.. I think, in the old days there was a POSI additive. and actuallly many years ago used whale oil... not enuf left to go around.... too many limited slips now. since 72 ive had chevys with posis or l/slips, and managed to wear out and trash a couple. you know somethings wrong when the wheels bind up going around a corner you can feel the tension and pressure in the drive train.. I until today thought you still added "posi" traatment ( about 10 ounces) when you change rear end lube.. what the other guys have posted has changed my mind, but im gonna ask a friend that is a line tech at the dealer I bought my truck at just in case..... I,m going to change my oil when I add ...mod.... a chrome or aluminum rear end cover... the rear cover sure looks close to the rear track? locating bar that is stamped steel.. wonder when rancho or somebody will make a modded track bar..... darn it one mod leads to another
 
victory_red said:
Thank you Steelheadchaser for making that point clear! ?Limited Slip,locking rear end,posi-trac, and trac-lock are all common terms used to describe the same thing. :B: :B: :B: :B:
Click to expand...
Well, almost. I wasn't going to confuse the issue any further but here I go. Real "lockers" can lock up solidly, that is if the left wheel turns one revolution, so will the right. These only work off-road. An example of these would be the ARB air locker. An other type, the Detroit locker, operates much the same as a ratchet. A Detroit is not very smooth and will usually clunk its way through turns. It too is usually used as an off-road diff.
 
You are once again right steelheadchaser.The term trac-lock is used by ford when talking about their limited slip units in their 8.8 rear-ends. They are much like the eaton units with the clutches. They also offer one like the auburn unit that uses "cones" instead of the clutches. These seem stronger but are not rebuildable like the clutch units. They are also a little bit more quieter than the detroit unit.
 
i know, what I myself have done, and last night i was thinking about my limited slip z71 diff. i dead all your guys answers, and the eaton web page... a couple times lately, i must admit, the streets were a little wet and upon turning a corner, I wound her up spinning only the right rear al the way up to the bup bup bup bup bup of the rev limiter. i read in this post that the " posi" effect is negated over 20 mph by the fly wieght that cancels the posi after 20 mph. then i said to myself when does the posi work????? off roads at low speeds RIGHT thats whhen we need it>> well what me myself and I did was, on the way home, there is one nieghbor that complained one time about the motorcycle noise woke up his baby, so...... I kinda pulled over and let the right rear be on his grass and the left on the street. I power braked it up a bit and you know what the tire on the street went chirp, chirp chirp, the tire on the street got the power do i have a posi limited slip??? yes i do cause my av told me so.... kinda taking the long way home tonite
 
posi trac and limited slip are not the same! Posi rear ends have gears locked together so both wheels get same power ALL the time. limited slip has clutch packs in the side carrier gears that transfer power to the wheel with traction so the wheel that has no traction wont turn. This from an ase master certified auto tech who also is a certiified AV nut. Limited slip diffs do have to be serviced periodicaly to maintain lubrication properties for the clutches, ther is a special additive and lube. :B:
 
rjlack,,,, have you hooked up on the..........the right tire is on something slipper, and the left one does the pulling so I know ithe rear end is biased to the traction??/ i dont get off road, but at a slippery boat ramp pulling out, my$ wheel drive Will pull me out on......theright rear and or the left rear..... now Ive got a question for the av mind what goes on up front????? is the teaction and pilling power of the front axle only 1 wheel, or will the energy shift to the wheel with the most traction like last night when I tested the rear diff?????
 
TexAVfan said:
posi trac and limited slip are not the same! Posi rear ends have gears locked together so both wheels get same power ALL the time. limited slip has clutch packs in the side carrier gears that transfer power to the wheel with traction so the wheel that has no traction wont turn. This from an ase master certified auto tech who also is a certiified AV nut. Limited slip diffs do have to be serviced periodicaly to maintain lubrication properties for the clutches, ther is a special additive and lube. :B:
Click to expand...
Actually, positraction is a GM brand name for a limited slip differential. It does not lock up solidly. If it locked up solidly, it would be pure hell on tires in an on road vehicle.
If anyone is interested in all the different types of differentials, Ring & Pinion has an excellent website that will guide you through the maze.
 
ALCON,

No word back from Eaton WRT G80 Locking axle service.

My '96 AWD Astro has the G80 axle, requires SAE 80W-90 GL5 lubricant, to be drained and filled at 3,000 miles and checked thereafter (unless towing). The repair manual specifically warns against using limited slip additive. The front axle is to be replenished as required.

IAW the AV Owner's manual, the front and rear axles lubricant levels are to be checked at 7,500 miles and replenished; 80W-90 front and 75W-90 rear, as required. No mention of limited slip additive.

I will probably drain and refill both axles at 3,000 miles. I would check to see if there are drain plugs, I hope so, but my AV is underway with the wife.

Aloha,
Murman :cool:
 
I know this is a little off the subject but has to do with differentials and there seems to be an abundance of knowledge about differentials on this post. My Av Z66 has an annoying hum that can be heard from 45 to 60 mph. It is most pronounced with light pressure on the accelerator. I've been to the Chevy dealer once. He confirmed that the hum was louder than most that he's heard - suggested that I drive it another 2000 miles which I did. He also indicated that he felt it was the differential making the hum. Since the visit to the dealer I changed the rear oil twice using synthetic 75w-90. On one of the changes I used a qt. of Lucas (in an attempt to quite down the hum). What I'd really like to know is 1. Is this normal? 2. Will it eventually go away? 3. Will there be any adverse effects on the differential?
Thanks, Ron
 
Ron,

While the Lucas products are probably very good, I would think twice about adding anything to the differentials, transfer case, and transmission not specifically recommended by GM. These pieces of equipment are not the same as their ancestors of the past. They have evolved into high-tech black boxes similar to the way the engine and its components has in the past 10 years.

The other side of the equation is the warranty issue. If you do end up having a real problem with the differential, additives, if found in the diff., would prbably void the warranty.

Just my $.02 worth.

Boo.
 
Boo:

Thanks for the input and good advice. I'll be changing to all synthetic diff. oil this afternoon.

Ron
 
ron the drive axle has 3 ways of handling power
#1 accelerating
#2coasting(float)
#3decelerating
which of the three ways does your noise come from? a baclash set up on the ring and pinion will "howl"..but it could run forever
 
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