Rear differential walmart gear oil good or no

[TByuri]

Long story short I hit a curve and ruined my rear differential on my 2002 lt.

Went to the junk yard and got one off a 2004 ls.

I'm going to put it in tomorrow but wondering about the gear oil.

I know I'm going to need about 2.5 quarts or so but wondering if this Wal-Mart 75w90 Super Tech Syn-Blend Gear Oil will work. Pretty cheap but just want to see if its a yes or no about meeting specs or whatever.

Thanks.

 

[Playsinsnow]

I don't but I know others who use it with no ill effects.

Mobil1 with LS additive ftw if it has the G80 locker.

75w90 is the weight/spec. You'll be fine as long as the new diff passes inspection.

 

[glfredrick]

The Walmart oil is fine, but realize what it is... Walmart uses recycled oil to "recrack" and make "semi-synthetic" -- not a problem at all since the oil itself is fine after going through the refinery process again. It is a Group III type oil that is called "semi-synthetic" because of this refinery technique (and additive package) but it is still a dino-based oil, unlike the PAO-based Group IV offerings.

I've found over the years that a true synthetic oil like Group IV Amsoil to be better for two reasons -- it flows out in extremely cold temps unlike the Group III types, which use friction and viscosity modifiers (Group IV do not need to use modifiers for either friction or viscosity -- the PAO base oil does not require them) and it carries more load rating.

I just changed the oil in the diffs of my Toyota Rav4 to Amsoil severe gear 75W-90 and picked up 2 mpg. It drives away MUCH smoother (feels like it is on ball bearings) than it did with the slow-to-warm Group III version that I replaced.

 

[The_Roadie]

GM specifies full synthetic. I use Mobil 1. It's not that expensive.

 

[CaptainXL]

Went to the junk yard and got one off a 2004 ls.

Before installing you checked bearings and replaced the pinion and both left and right axle seals I hope?

 

[HARDTRAILZ]

Be sure to give it a good once over, but I am not sure why someone would recommend replaces seals that may be perfectly good. Myused axle did not get new seals when it went in. They all looked fine and have performed as such.

Mobil 1 has been the go to diff fluid for most and it is not expensive really. With my current setup I use the cheapest stuff available due to frequent changes, but if you are going to not change until typical intervals, I would spend a few extra pennies and get Mobil or similar.

 

[STLtrailbSS]

I used Royal Purple. I originally changed it with Mobil1 with ACdelco addictive and to this day I have no explination the oil disappeared changing rotors one day and checked it and the sh*t was gone pinky could not feel any fluid what so ever. Didn't touch the gasket drained the Mobil replaced with purple. Was just under the truck 2-3 moths ago getting rid of air ride royal purple has not lost a drop.

 

[jsheahawk]

+1 to Royal Purple. It's a little more expensive, but it's not an every 3,000 mile thing.

Jared

 

[TByuri]

Ok went to autozone and they only had one quart of the mobile 1 75w 90.

So I got two quarts of valvoline synpower full synthetic 75w90 limited slip vv975.

Its a 2004 rear diff am I ok before I fill it? Rear is in now. Thanks.

 

[IllogicTC]

Did you confirm that the new differential's gear ratio matched your old one? I know it's a bit late to ask now, but may as well double-check.
The LS additive is only necessary if the new differential has the G80 option installed. The vehicle it's pulled from would have this code along with the differential size code (GU6, GT4, GT5) in the glove box on the RPO sticker.

 

[TByuri]

Its off a 2004 trailblazer ls with third row seating I remember but did not check the glove box.

Ill take the rear covers off both and check the numbers.

Either way I'm good with the fluid right? The limited slip on both the mobile 1 and the valvoline wouldn't hurt it right?

Ok hard to see but I think its like a 86 on this new 04 rear reading on the gear.

And an 8.0 on my old 2002 rear. Is this going to be a problem.

I've read you can you can put the newer ones on the older 02 trailblazers but want to make sure.

 

[triz]

The Walmart oil is fine, but realize what it is... Walmart uses recycled oil to "recrack" and make "semi-synthetic" -- not a problem at all since the oil itself is fine after going through the refinery process again. It is a Group III type oil that is called "semi-synthetic" because of this refinery technique (and additive package) but it is still a dino-based oil, unlike the PAO-based Group IV offerings.

I've found over the years that a true synthetic oil like Group IV Amsoil to be better for two reasons -- it flows out in extremely cold temps unlike the Group III types, which use friction and viscosity modifiers (Group IV do not need to use modifiers for either friction or viscosity -- the PAO base oil does not require them) and it carries more load rating.

I just changed the oil in the diffs of my Toyota Rav4 to Amsoil severe gear 75W-90 and picked up 2 mpg. It drives away MUCH smoother (feels like it is on ball bearings) than it did with the slow-to-warm Group III version that I replaced.

For the OP...

AMSOIL Severe Gear® 75W-90

Couple that with an oil change and you might see another increase in MPGs.

 

[TByuri]

Ok so I opened the covers on my original damaged 2002 rear and saw that the gear said 8.0.

My new 2004 rear from an ls I think said 86. Hard to read.

I put it on and went go get gas after I filled it with the valvoline synthetic.

Is there any problem I will run into? I read around here on the old threads that the newer differentials can be used on the old trailblazers.

Any help or comments are appreciated.

 

[Playsinsnow]

Ok so I opened the covers on my original damaged 2002 rear and saw that the gear said 8.0.

My new 2004 rear from an ls I think said 86. Hard to read.

I put it on and went go get gas after I filled it with the valvoline synthetic.

Is there any problem I will run into? I read around here on the old threads that the newer differentials can be used on the old trailblazers.

Any help or comments are appreciated.

From what I understand is you put a rear diff for a larger rear axle. The swb's use an 8" axle. EXT's an 8.6. Double check the gear ratios too with the RPO code...

 

[IllogicTC]

From what I understand is you put a rear diff for a larger rear axle. The swb's use an 8" axle. EXT's an 8.6. Double check the gear ratios too with the RPO code...

The gear ratios remain the same between the two axle sizes, fortunately... I'm just curious if it's the right ratio. He doesn't have 4x4 so luckily no sweating a bind-up there, main difference is will the system be in the right calibration for VSS and other things which require velocity readings off the rear end? If he lucked out and got the exact same rear ratio, then he is absolutely good to go.

And it's a shame we don't have the GL3 axle (6.17 ratio)

 

[TByuri]

If it means anything there's 11 41 before the ratios of 8.0 and 8.6 present on both of these rears.

The numbers after are different though like 300 something and 200 something on one and the other.

 

[Playsinsnow]

You could count the grooves/teeth on the ring gear. That would tell you the size...

 

[IllogicTC]

You could count the grooves/teeth on the ring gear. That would tell you the size...

Popping the rear cover, the ring gear has a stamping telling you how many teeth there are on both the ring and pinion

If it means anything there's 11 41 before the ratios of 8.0 and 8.6 present on both of these rears.

The numbers after are different though like 300 something and 200 something on one and the other.

Both had that? Should be good to go. GM Axles have I believe a serial number, then those digits, then it says GM, then something else.

41 is the ring gear. 11 is the pinion. 41/11 = 3.73 gear ratio. That's if you got those numbers off the ring gear stamping. They may also stamp it on the outside too now, I don't know.

Tell you what, though. Get us the RPO code in your glove box - there's a big list of codes and you'll either have a GU6, GT4, or GT5 in the list. Then we know what gear ratio came stock with your truck, and if it's GT4 then my theory on that stamp is proven (if it was found on the exterior of the axle). Get that gear oil in there like you wanted, and then go on a test drive, say at 55MPH, with a friend in another car or with a GPS. Either could validate you're going 55MPH. Note that the GPS may say you're going 54 or 53 or something, this may be normal (mine does it). If it's not reading 5 over or under, you're alright.

 

[blazinlow89]

If it means anything there's 11 41 before the ratios of 8.0 and 8.6 present on both of these rears.

The numbers after are different though like 300 something and 200 something on one and the other.

This is the ring gear size, not the ratio. If you have not filled it with fluid yet then you should be able to pull the cover and read the stampings on the outside edge of the gear. Look for a long code, from what I am seeing it will say "GM" then some numbers, and possibly one with say 11-41 followed by more numbers. I am not saying this is accurate but is usually the case for OEM gears.

You could count the teeth on both the pinion and ring, then divide the ring gear number by the pinion to get your axle ratio. You could also find out the donor truck and get the rpo codes from the glove box. If it cam from a scrap yard, good luck.

However seeing as you ask about the 11 41 before the gear size, it may be safe to assume that you have the 3.73 gear ratio. If it is the same as before then sweet, you upgraded your axle and managed to keep the same ratio.

The ratio basically goes like this. Lets go with your 3.73/1 ratio, for every 3.73 turns of the pinion gear, the ring gear will turn 1 time. Lower gear ratios work better for towing and acceleration, while higher ones (like the 3.42 in my truck) would be better for gas mileage.

Illogic, I started typing that earlier and went to do some research on the stampings, walked the dog and came back to finish the post.

 

[TByuri]

Unfortunately I already had filled it and the rear came from the scrap.

Ill drive around and report back.

I put it in 2 quarts basically, had a tiny bit left.

Anybody know the exact amount for this 2004 rear end, with 11 41 8.6 stamped. Thanks all.

 

[Playsinsnow]

Check this link out.





http://gmtnation.com/f79/drivetrain-fluids-specifications-197/

Unfortunately I already had filled it and the rear came from the scrap.

Ill drive around and report back.

I put it in 2 quarts basically, had a tiny bit left.

Anybody know the exact amount for this 2004 rear end, with 11 41 8.6 stamped. Thanks all.

I just filled it until it started seeping out and plugged it when the leaking stopped. This is how you check the level, COLD (!).

 

[TByuri]

Im thinking about continuing to drive it for a day or two and then try to fill it again just in case I need a little more?

I put like 1.7quarts in. Is it a good idea to just make sure im topped off again after a day or two of driving?

 

[CaptainXL]

Im thinking about continuing to drive it for a day or two and then try to fill it again just in case I need a little more?

I put like 1.7quarts in. Is it a good idea to just make sure im topped off again after a day or two of driving?

All chevy light duty rear ends (for as long back as I can remember) say to fill the differential until the fluid starts overflowing out the hole. The last time I changed my fluid it was a tad more than 2 quarts. It depends if you are on a perfectly level surface or not. Which you should be.

 

[The_Roadie]

1.8 qts is what GM calls for on these rearends.

I seem to recall that from the shop manual as well, but dug a bit deeper just now. The 2006 Owner's Manual for instance, has fluid capacity listed only for the transfer case and not for the diffs. They say to fill them by checking level through the fill hole, and definitely on a level surface.

View attachment 32902

 

[CaptainXL]

To continue off of that, the rest of the steps are as follows:

9.If the fluid level is low, add lubricant until the level is even with the bottom edge of the fill plug opening. Use the proper fluid. Refer to Fluid and Lubricant Recommendations.

10.Install the rear axle fill plug. Tighten the rear axle fill plug to 33 Nm (24 ft. lbs.).

Obviously if you need to fill it until it is even then that means it needs to be filled up all the way and not 10mm below. 10mm below would be borderline.

 

[glfredrick]

GM specifies full synthetic. I use Mobil 1. It's not that expensive.

Mobil 1 can be Group III or Group IV depending on the product, but it IS the oil that GM specs for Vettes, etc.

 

[CajunWon]

I used Royal Purple. I originally changed it with Mobil1 with ACdelco addictive ......

With Royal Purple: Do we need to use the Ltd-Slip additive (GM P/N 1052358 or equivalent) ?

 

[CaptainXL]

With Royal Purple: Do we need to use the Ltd-Slip additive (GM P/N 1052358 or equivalent) ?

No. The website says it is already formulated for Limited Slip Differentials. So it can be used in the locking and LS diffs the same.

Max Gear - High Performance Gear Oil | Royal Purple - Synthetic Motor Oil & Performance Lubricants