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Gear Oil Change


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#1 gvbhunt

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Posted 21 May 2008 - 10:04 AM

Ok, I am planning a fun weekend of working on cars... Need to do a couple of oil changes, rotate tires, fun stuff like that. My truck is getting close to 12k miles and the wife's 'Ho is up around 25k. I was thinking that since we plan to keep these vehicles it is probably a good idea to do more than just the standard "gonna trade it in soon" maintenance. I was thinking that a good place to start would be the front and rear axle. The engines already get a good synthetic and low micron filters so that part is covered. I figured that a good synthetic in the front and rear end would be something that they would like. My truck has the 9.5" rear and from what I can tell from the service manual and without getting under the truck is that it has a fill plug and a drain plug. My wife's I am assuming that since it is the 8.6" (I think) I am going to have to pop the cover off since it probably only has a fill plug. I have never done any maintenance to an independent front axle so I am about clueless there.

So my questions are;
1. Do I have to remove the cover on the 9.5" and does it actually have a drain plug?
2. Since I will probably have to remove the cover on the Tahoe's rear (unless I am wrong) does the cover have a seal built onto it or do I need to get a gasket or is it a RTV job?
3. Only worked on solid front axles and the service manual only shows a drain plug on the front axle. Where the heck do I fill it from and is it the same procedure? Fill till you can just feel the oil when you stick your finger into the fill plug/hole?
4. Anything else I need to consider before starting?

FYI, Truck is a 2007 Sierra VMax 4x4. Wife's is a 2007 Tahoe 5.3L 4x4. Plan on using Amsoil Severe Gear 75W90.

Thanks in advance.

Brad
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#2 slimjim2525

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Posted 21 May 2008 - 10:37 AM

Ok, I am planning a fun weekend of working on cars... Need to do a couple of oil changes, rotate tires, fun stuff like that. My truck is getting close to 12k miles and the wife's 'Ho is up around 25k. I was thinking that since we plan to keep these vehicles it is probably a good idea to do more than just the standard "gonna trade it in soon" maintenance. I was thinking that a good place to start would be the front and rear axle. The engines already get a good synthetic and low micron filters so that part is covered. I figured that a good synthetic in the front and rear end would be something that they would like. My truck has the 9.5" rear and from what I can tell from the service manual and without getting under the truck is that it has a fill plug and a drain plug. My wife's I am assuming that since it is the 8.6" (I think) I am going to have to pop the cover off since it probably only has a fill plug. I have never done any maintenance to an independent front axle so I am about clueless there.

So my questions are;
1. Do I have to remove the cover on the 9.5" and does it actually have a drain plug?
2. Since I will probably have to remove the cover on the Tahoe's rear (unless I am wrong) does the cover have a seal built onto it or do I need to get a gasket or is it a RTV job?
3. Only worked on solid front axles and the service manual only shows a drain plug on the front axle. Where the heck do I fill it from and is it the same procedure? Fill till you can just feel the oil when you stick your finger into the fill plug/hole?
4. Anything else I need to consider before starting?

FYI, Truck is a 2007 Sierra VMax 4x4. Wife's is a 2007 Tahoe 5.3L 4x4. Plan on using Amsoil Severe Gear 75W90.

Thanks in advance.

Brad

They may already come with synthetic from the factory.
2007 GMC Sierra 1500

#3 95Sierra2500

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Posted 21 May 2008 - 11:45 AM

I would check to see if they came with synthetic from the factory. Find out what fluid is recommended and find out if it's synthetic or not. If it's not, proceed with changing the fluids.

As for your rearend that has no drain plug, TYPICALLY you have to pull the cover. After that there are two trains of thought. One is to skip the gasket and just use gasket maker/RTV, the other is to buy the gasket and install it. Personally (because I hate leaks) I put a thin bead of RTV on both sides of the gasket and install it that way. I've never had a rearend leak from that. I would consider pulling the cover on your rearend that has a drain plug too, but it wouldn't be necessary (provided it really DOES have a drain plug - I haven't seen many that do).

For the IFS differentials, there should be a fill plug higher up, but it will be difficult to see. On my wife's '99 Jimmy, the plug is tucked in on the front side where it can only be seen if you remove the rock shields. My truck is the same way, though harder to see. I can only get the plug out if I bear-hug the differential case.

As for what oils to use, Amsoil and Royal Purple are about the best you can buy. HOWEVER, make sure to get the proper weight oils - don't just assume they need 75W90. If that is what the manual calls for, so be it, but there are some applications (for example, my '95 2500 or my dad's '94 3500) where the rearend calls for 85W90 or other weights. I cannot stress enough how important it is to get the proper weight oil in gear applications. Too heavy of a gear oil can lead to higher shear loads, which can break down the oil prematurely (not as big of a problem with synthetic, but still a problem), thus causing more frequent lube changes or differential failures if not monitored. Too light of a gear oil can allow the gears to wear more heavily on each other, wearing out the gears and causing differential failures. These gears are designed for particular weights of lube - Use them.
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#4 gvbhunt

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Posted 21 May 2008 - 02:46 PM

I would check to see if they came with synthetic from the factory. Find out what fluid is recommended and find out if it's synthetic or not. If it's not, proceed with changing the fluids.

As for your rearend that has no drain plug, TYPICALLY you have to pull the cover. After that there are two trains of thought. One is to skip the gasket and just use gasket maker/RTV, the other is to buy the gasket and install it. Personally (because I hate leaks) I put a thin bead of RTV on both sides of the gasket and install it that way. I've never had a rearend leak from that. I would consider pulling the cover on your rearend that has a drain plug too, but it wouldn't be necessary (provided it really DOES have a drain plug - I haven't seen many that do).

For the IFS differentials, there should be a fill plug higher up, but it will be difficult to see. On my wife's '99 Jimmy, the plug is tucked in on the front side where it can only be seen if you remove the rock shields. My truck is the same way, though harder to see. I can only get the plug out if I bear-hug the differential case.

As for what oils to use, Amsoil and Royal Purple are about the best you can buy. HOWEVER, make sure to get the proper weight oils - don't just assume they need 75W90. If that is what the manual calls for, so be it, but there are some applications (for example, my '95 2500 or my dad's '94 3500) where the rearend calls for 85W90 or other weights. I cannot stress enough how important it is to get the proper weight oil in gear applications. Too heavy of a gear oil can lead to higher shear loads, which can break down the oil prematurely (not as big of a problem with synthetic, but still a problem), thus causing more frequent lube changes or differential failures if not monitored. Too light of a gear oil can allow the gears to wear more heavily on each other, wearing out the gears and causing differential failures. These gears are designed for particular weights of lube - Use them.

You are correct. There is Syn in the rear end but oddly enough it is not in the front...

Front Axle (1500 Series)
SAE 80W-90 Axle Lubricant (GM Part No. U.S. 89021671, in Canada 89021672).
Front Axle (1500 HD, 2500, 2500 HD, and 3500 Series)
SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 89021677, in Canada 89021678) meeting GM Specification 9986115.
Rear Axle
SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 89021677, in Canada 89021678) meeting GM Specification 9986115.

Plus I found this as well...

Rear Axle Lubricant Replacement (9.5 LD Axle)
Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
Remove the rear axle drain plug.
Drain the lubricant into a suitable container.
Inspect the drain plug for excessive metal particle accumulation. This accumulation is symptomatic of extreme wear.
Clean the drain plug.

So maybe I only have to pull the cover on the Tahoe as it has the lighther rear end.

So, since it already has syn in the rear would it be a good idea just to change it for the same reason that you change the "break in" oil in the engine to get rid of the initial wear materials?

And since the front is aparently not synthetic would changing it for the same reason be a good idea, plus to change it over to Syn?

I am asking this because I am not too accustomed to changing fluids in axles. I only recently changed the front and rear in my Wrangler, which has 131k miles on it, because I had it buried in a pond and wanted to make sure that there was no moisture in it. And I have never had a problem with it (Well, not with the axles.....)

Am I on the right track?
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#5 iminaquagmire

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Posted 21 May 2008 - 03:15 PM

Yes you are. I would actually pull the cover on both, and seal them back up with some RTV. At least on yours as I don't know about the tahoe, I would also clean up and spray some undercoating on the outside of the cover. They either don't come painted from factory, or they do a very poor job. Mine is covered in rust. You do not want to have the cover rust through and lose you gear oil. BTW, the Royal Purple gear oil is some good stuff.
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#6 bobf1234

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Posted 21 May 2008 - 03:51 PM

If I were you I would just go ahead and be thorough about it... Pull the covers on both, clean all the old oil off and any metal particles. Seal them up and fill them with Royal Purple...
Thats some good stuff.

#7 gvbhunt

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Posted 27 May 2008 - 01:05 PM

Ok, just FYI for anyone that wants to do this.

2007 GMC Sierra MAX with 9.5 inch rear end DOES have a drain plug on the bottom of the axle. Makes it much easier to swap the fluid out. Changing out the front was just as easy. Remove the skid plate and you have easy access to both the drain and fill plug.

Same deal on the 07 Tahoe, front end was easy. Exactly same as the truck but it had no skid plate so it took less time. Now the rear end was a different story. No plug. Went to parts store (will not name names as O'reilley's may be monitoring this thread) and they had NO clue as to what the gasket for the rear end was, Gomer told me that his book only went to '97. It shows it in the Helm service manual but with no part number. So that will have to wait.

The rear end of the truck was pretty clean. Only has 12k miles on it and the gear oil was looking good. The front on it as well as the Tahoe both showed quite a bit of metal so I am glad that they got switched out.

Now for synthetic in the tranny and transfer case...

Also I found that there was a bit of oil above the skid plate coming off of the steering rack. What a pisser....
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Modifications: True Flow PAI, HPTuned (Removed HUGE PE Delay, Added 30 to speed limiter, modified AFM/DOD for better MPG)

#8 MS3DALE

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Posted 27 May 2008 - 01:22 PM

Also I found that there was a bit of oil above the skid plate coming off of the steering rack. What a pisser....


Theres an "EI" TSB for that.....


Service Information
Document ID: 2079333
--------------------------------------------------------------------------------

#07-02-32-002D: EI07082 - Power Steering Fluid Leaking from Power Steering Gear/Rack Assembly (Engineering Information) - (Mar 12, 2008)


Subject: EI07082 -- Power Steering Fluid Leaking from Power Steering Gear/Rack Assembly (Engineering Information)


Models: 2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2008 Chevrolet Impala

2007-2008 GMC Denali, Sierra, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL

1500 Series Only



Attention: Proceed with this bulletin ONLY if the customer has commented about this concern AND the EI number is listed in GMVIS, otherwise disregard the bulletin and proceed with diagnostics found in the published service information. **THIS IS NOT A RECALL**

Refer to Service Bulletin 04-00-89-053A for more detail on the use of Engineering Information Bulletins.



--------------------------------------------------------------------------------

This bulletin is being revised to add the 2008 Chevrolet Impala, part information and engineering contact information for the Impala. Please discard Corporate Bulletin Number 07-02-32-002C (Section 02 -- Steering).


--------------------------------------------------------------------------------

Condition
Some customers may comment on a fluid leak. Upon investigation, the technician may find fluid leaking from the power steering system.

What Action to Take
Important: All potential leaks should be completely cleaned and identified before attempting to repair or replace any power steering components.

Start diagnosis by inspecting the fluid level in the Power Steering Reservoir. If the fluid level is NOT low, a careful analysis of the condition is necessary as it may involve a different type of fluid leak.
Visually inspect the components where the fluid has accumulated.
Completely clean off any fluid residue from the suspect components.
Apply tracing powder to the suspect components. This is an effective way to determine the source of a leak. As an alternative, fluorescent dye (such as Kent Moore J 28431-6) may be added to the power steering fluid.
Start the vehicle and allow the power steering system to reach normal operating temperatures.
Turn the steering wheel to the stops in each direction while bumping the steering wheel against the stops 3-4 times. This will build maximum steering system pressure and help identify the source of the leak if present.
Determine the source of the leak.
If a repeatable leak is found, use the following tables to determine if the condition is repaired and what corrective action is needed.
Repairable Leaks
Source of Leak
Correction

Pressure feed and return hoses/lines
Replace seals, hose, or line set

Power steering pump
Reseal or replace pump if necessary

Cylinder gear/rack lines
Replace O-ring seals or rack lines


Non- Repairable Leaks
Source of Leak
Correction

Porosity leak in the gear/rack housing
Replace steering gear/rack

Leak from tie rod boots

Pinion seal

Repeatable leak at steering gear adjuster plug*
See note below


*If fluid is observed at the adjuster plug during the initial visual inspection, then refer to the following:


Seepage at the adjuster plug may not necessarily indicate an active leak. Power steering fluid is used during the manufacturing of the gear/rack. The fluid used at assembly is pushed into the pinion area during assembly. The adjuster plug and the area below the pinion are not positively sealed. Fluid trapped in this area during assembly may seep from the adjuster plug. The rack should not be replaced for this condition.

You can distinguish seepage from an active leak by removing the left tie rod boot clamp and inspecting for the presence of fluid at the inner tie rod.

If no fluid is found in the left tie rod boot, replace the boot clamp and clean the seepage from the rack. No further action is needed.

If fluid is found in the left tie rod boot, replace the gear assembly.

Engineer Contact Information:
Contact the appropriate engineer for additional information or guidance before repairing the vehicle. This call may result in a personal visit to your dealership or a special request to return parts that exhibit unique conditions. In either case, you should receive a response back within 2 hours on what action to take the same business day of your call (Eastern Daylight Time).


If you do not receive a response from engineering, then proceed to repair the vehicle. Use normal diagnostics and claim the repair work under the appropriate warranty labor operation.

GM Engineering is working to determine the root cause of the above conditions. GM Engineering has a need to obtain information during diagnosis and BEFORE repair. As a result, this information will be used by engineering to "root cause" the customer's concern and develop/validate a field fix.

Parts Information
Fullsize Truck and SUV: Part Number
Description

15254058
Pipe Kit, Steering Gear

15254059
Pipe Kit, Steering Gear

11562064
Clamp, Crimp

(Boot to Rack)

11562066
Clamp, Spring

(Boot to Tie Rod)

26100863
Seal, Power Steering Gear Inlet and Outlet Hose

26081619
Seal, Steering Gear Cylinder Pipe

(O-ring)


Impala: Part Number
Description

26065126
Pipe Kit, Steering Gear (Short)

26055484
Pipe Kit, Steering Gear (Long)

26035404
Boot Kit, Steering Gear


Warranty Information
Important: DO NOT use the labor operation listed below if engineering did not respond.

For vehicles repaired under engineering direction, use:

Labor Operation
Description
Labor Time

E9451*
Engineering Information-Power Steering Leak
0.6 hr

Add
Repair per Engineer Direction
Use Actual Repair Order Clock Time

*This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


2008 General Motors Corporation. All rights reserved.

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#9 slimjim2525

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Posted 27 May 2008 - 01:31 PM

Ok, just FYI for anyone that wants to do this.

2007 GMC Sierra MAX with 9.5 inch rear end DOES have a drain plug on the bottom of the axle. Makes it much easier to swap the fluid out. Changing out the front was just as easy. Remove the skid plate and you have easy access to both the drain and fill plug.

Same deal on the 07 Tahoe, front end was easy. Exactly same as the truck but it had no skid plate so it took less time. Now the rear end was a different story. No plug. Went to parts store (will not name names as O'reilley's may be monitoring this thread) and they had NO clue as to what the gasket for the rear end was, Gomer told me that his book only went to '97. It shows it in the Helm service manual but with no part number. So that will have to wait.

The rear end of the truck was pretty clean. Only has 12k miles on it and the gear oil was looking good. The front on it as well as the Tahoe both showed quite a bit of metal so I am glad that they got switched out.

Now for synthetic in the tranny and transfer case...

Also I found that there was a bit of oil above the skid plate coming off of the steering rack. What a pisser....

Good job, you've encouraged me to do mine by myself. I can't believe the donkeys only had a twelve year old manual.
2007 GMC Sierra 1500

#10 gvbhunt

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Posted 27 May 2008 - 01:41 PM

Thanks Rich. I am going to have to compile a list (a very short one) of stuff when I take the truck in.
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2007 GMC Sierra Z71 SLT Crew Cab 4x4 6.0L 4l70e 3.73 gears 5000k HID low beam and driving light upgrade.
Modifications: True Flow PAI, HPTuned (Removed HUGE PE Delay, Added 30 to speed limiter, modified AFM/DOD for better MPG)