# Rear End service



## Pablo (Jan 9, 2009)

I have a 2006 GTO with 40k miles. Was in a quick lube place for my oil change and they asked if I wanted the rear end fluids changed. They said that the factory recomendation is every 30k miles. I could not find this in the manual... any suggestions?

:willy:


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## CChase (Dec 11, 2007)

Pablo said:


> I have a 2006 GTO with 40k miles. Was in a quick lube place for my oil change and they asked if I wanted the rear end fluids changed. They said that the factory recomendation is every 30k miles. I could not find this in the manual... any suggestions?
> 
> :willy:


Do it, although personally I'd do it myself.

This is what mine looked like after 18k:


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## jpalamar (Jul 22, 2008)

I would have it done just to be safe, also have your trans fluid done also while its in the air.


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## GTO JUDGE (May 14, 2005)

YOU NEED THE FRICTION MODIFIER. 

I DOUBT THOSE LUBE PLACES EVEN KNOW ABOUT THIS. 

If you trust them enough, take the F.M. with you and watch and make sure they add it.


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## jpalamar (Jul 22, 2008)

Once my rear starst to whine, I'm taking it to one of those shops and letting them put the wrong fluid in, then making then buy a new rear when its fails  Just messing.

On a side note, one of my friends works for Sears while he is in school. He said they got a new machine that is supposed to be a universal diff/tranny fluid machine. Apparently it works with all cars.

I haven't been brave enough to test it though.


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## Poncho Dan (Jun 30, 2009)

I bet that bottle smells like burned crayons pretty bad.


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## CChase (Dec 11, 2007)

Poncho Dan said:


> I bet that bottle smells like burned crayons pretty bad.


Burned crayons mixed with some 3 month old bananas.


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## Pablo (Jan 9, 2009)

Thanks for all the advice...going to get it changed (with friction modifier)
.....


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## AlanSr (Jan 4, 2008)

Does Royal Purple come with Friction modifier?


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## chilliwhiggerE (Mar 10, 2009)

I am servicing my differential next week when I install my Harrop mount and FULL bushing kit. I'm using 75/140 Amsoil Severe Gear. It already has the friction modifier in it. 75/140 is the factory viscosity.


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## Cobra126 (Sep 24, 2009)

chilliwhiggerE said:


> I am servicing my differential next week when I install my Harrop mount and FULL bushing kit. I'm using 75/140 Amsoil Severe Gear. It already has the friction modifier in it. 75/140 is the factory viscosity.


 Are you sure the Amsoil will be OK in the GTO rear? When I tried to find some on their site, they showed no rcommendations for the GTO's.


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## chilliwhiggerE (Mar 10, 2009)

Cobra126 said:


> Are you sure the Amsoil will be OK in the GTO rear? When I tried to find some on their site, they showed no rcommendations for the GTO's.


I conferred about this with a representative for Amsoil on another site and he said it should be good as long as you make sure to get the 75W/140. Some retarded people tried to run thinner lube and ran into chatter problems but said that adding some more modifier cleared it up. I cannot tell you from personal experience but I will know shortly. I'll keep you posted.
The link is in this thread for the Lube http://www.gtoforum.com/f2/what-do-u-consider-abuse-23830/


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## chilliwhiggerE (Mar 10, 2009)

I used the Amsoil without the modifier for a week now and have experienced no problems. Posi all day long.


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## GTO JUDGE (May 14, 2005)

chilliwhiggerE said:


> I used the Amsoil without the modifier for a week now and have experienced no problems. Posi all day long.


Let us know in a few months if the rear diff is still silent. There is a reason the F.M. is to be installed. If the noise begins and it stays even after you decide to install it.... think about the short cut ya took. Not flaming... just my .02


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## FastFrank (Jun 12, 2009)

The Amsoil rep I contacted recommended using the OEM GM stuff. He said that Amsoil does not have a comparable product for our diffs. The Amsoil website says the same thing...
AMSOIL Online Product Application Guide - 2004%7cPONTIAC%7cGTO%7cG


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## jpalamar (Jul 22, 2008)

chilliwhiggerE said:


> I conferred about this with a representative for Amsoil on another site and he said it should be good as long as you make sure to get the 75W/140. Some retarded people tried to run thinner lube and ran into chatter problems but said that adding some more modifier cleared it up. I cannot tell you from personal experience but I will know shortly. I'll keep you posted.
> The link is in this thread for the Lube http://www.gtoforum.com/f2/what-do-u-consider-abuse-23830/


The new part number from GM uses 75W90 I think.



chilliwhiggerE said:


> I used the Amsoil without the modifier for a week now and have experienced no problems. Posi all day long.


Your rear is going to fail.



GTO JUDGE said:


> Let us know in a few months if the rear diff is still silent. There is a reason the F.M. is to be installed. If the noise begins and it stays even after you decide to install it.... think about the short cut ya took. Not flaming... just my .02


:agree You better put that FM in while you still have a change. Hopefully didn't cause any $$$ damage yet.


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## UdnUdnGTO (Jan 30, 2006)

Interesting, I have not had any problems with Amzoil in my differential. I added friction modifier and I have a lot of miles on the car. It has been doing great! I don't know what to say.


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## RicanGoat (Aug 25, 2009)

would Royal Purple be a viable option? Would it require the F.M. or is the OEM GM stuff with the friction modifier the safest bet? I want to service my diff but would like to get the best I can get; no shortcuts. Thanks.


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## jpalamar (Jul 22, 2008)

RicanGoat said:


> would Royal Purple be a viable option? Would it require the F.M. or is the OEM GM stuff with the friction modifier the safest bet? I want to service my diff but would like to get the best I can get; no shortcuts. Thanks.


I'm using Royal Purple 75W140. It has the friction modifier in it already.

Just a heads up. The fill bolt is massive. I'm talking like 30mm or so. I used a big ass adjustable wrench on mine. Drain plug is the bottom bolt on the diff. Its easy as well and with RP container with the pointed tip, you just squirt it in until it oozed out, then plug her up and your done. Takes forever to drain though with it being so think.


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## chilliwhiggerE (Mar 10, 2009)

GTO JUDGE said:


> Let us know in a few months if the rear diff is still silent. There is a reason the F.M. is to be installed. If the noise begins and it stays even after you decide to install it.... think about the short cut ya took. Not flaming... just my .02


The Amsoil 75w140 that I used is the Severe Gear and is supposed to have friction modifier in it already. If I were to put the modifier in it how much would you suggest that I use? 1-2 oz ect?


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## GTO JUDGE (May 14, 2005)

chilliwhiggerE said:


> The Amsoil 75w140 that I used is the Severe Gear and is supposed to have friction modifier in it already. If I were to put the modifier in it how much would you suggest that I use? 1-2 oz ect?


Your first post said it didn't have the F.M. in it that is what I based my response on. 

If it has the F.M. in it then you should be ok and I wouldn't add any more to it. 1 oz is the correct amount though.


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## FastFrank (Jun 12, 2009)

chilliwhiggerE said:


> The Amsoil 75w140 that I used is the Severe Gear and is supposed to have friction modifier in it already. If I were to put the modifier in it how much would you suggest that I use? 1-2 oz ect?


Amsoil 75w140 does not have fm in it. You have to add it yourself.


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## Poncho Dan (Jun 30, 2009)

Is there a place I can get the Royal Purple diff fluid online? There are no places in Wisconsin (no Pep Boys here) to get it, unless I drive all the way the hell down to Illinois for it.

Edit: nevermind, I found one.


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## chilliwhiggerE (Mar 10, 2009)

GTO JUDGE said:


> Your first post said it didn't have the F.M. in it that is what I based my response on.
> 
> If it has the F.M. in it then you should be ok and I wouldn't add any more to it. 1 oz is the correct amount though.


The Amsoil site says and I quote "Should be compatible with most limited slip differentials. "IF" chatter occurs ad friction modifier". I researched another comparison of several gear oils (the exact location escapes me at this time) and it said specifically that there were modifiers in it but that some differentials may require more. I had my friend follow me in his (quiet) acura tl last night and he said he heard nothing from the rear so I'm taking a wait and see in this one. If something changes I will post it in this thread immediately. If it does go wonky on me I'll get 3.73 to 1's in there! LOL 
I only drive 12 miles a day average at speeds below 50 mph and I am constantly listening to the car so if anything happens I'll know immediately. (believe me I am highly conscious of my car)


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## FastFrank (Jun 12, 2009)

chilliwhiggerE said:


> The Amsoil site says and I quote "Should be compatible with most limited slip differentials. "IF" chatter occurs ad friction modifier".


What you quoted conflicts with the recommended fluids that the Amsoil website provides. I posted a link in an earlier post. Here is a capture from that website that states that there is no Amsoil product recommendation, and that they recommend using the GM product.


Differential, Rear......GL-5*
ALL TEMPS......75W-140 [3]
* No AMSOIL Product Recommendation*
Fluids
Power Steering Fluid......AF3
Synthetic Universal Automatic Transmission Fluid (ATFQT)
Power Steering Fluid......AF3
Torque-Drive Synthetic Transmission Fluid (ATD1G)
Brake Fluid......HBH
 AMSOIL Brake Fluid DOT-4 (BF4SN)
Clutch Fluid......HBH
AMSOIL Brake Fluid DOT-4 (BF4SN)
[1] SAE 10W-30 is preferred.
[2] GM recommends Part No. 88861800 (Canada 88861801)
or equivalent for manual transmission, transfer
case applications.
*[3] Use GM part no. 89021809 Axle lubricant 75W-140.
Plus 1 ounce of friction modifier 7098 GM part
no.89021958 or equivalent*


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## GTO JUDGE (May 14, 2005)

chilliwhiggerE said:


> The Amsoil site says and I quote "Should be compatible with most limited slip differentials. "IF" chatter occurs ad friction modifier". I researched another comparison of several gear oils (the exact location escapes me at this time) and it said specifically that there were modifiers in it but that some differentials may require more. I had my friend follow me in his (quiet) acura tl last night and he said he heard nothing from the rear so I'm taking a wait and see in this one. If something changes I will post it in this thread immediately. If it does go wonky on me I'll get 3.73 to 1's in there! LOL
> I only drive 12 miles a day average at speeds below 50 mph and I am constantly listening to the car so if anything happens I'll know immediately. (believe me I am highly conscious of my car)


Whether you install it or not is up to you. I believe Frank has provided you Amzoil's recommendation. 

[The Amsoil site says and I quote "Should be compatible with most limited slip differentials.]
Operative word there is: *should* I can't say you'll experience chatter however after 5 years of people reporting rear end chatter it would stand to reason there is a more than likely chance at some point you will. I got it at 9500 miles with a new rear. Time will tell whether you'll eventually get it. IMO if the product label doesn't specifically say the F.M. is in the oil, I would add it if at the very least, for peace of mind. It is required by GM.


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## CChase (Dec 11, 2007)

I haven't heard any complaints about the new GM fluid with FM in it.


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## chilliwhiggerE (Mar 10, 2009)

GTO JUDGE said:


> Whether you install it or not is up to you. I believe Frank has provided you Amzoil's recommendation.
> 
> [The Amsoil site says and I quote "Should be compatible with most limited slip differentials.]
> Operative word there is: *should* I can't say you'll experience chatter however after 5 years of people reporting rear end chatter it would stand to reason there is a more than likely chance at some point you will. I got it at 9500 miles with a new rear. Time will tell whether you'll eventually get it. IMO if the product label doesn't specifically say the F.M. is in the oil, I would add it if at the very least, for peace of mind. It is required by GM.


I ordered a tube of FM it's on it's way.


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## symbian (Aug 7, 2009)

Does anyone have a DIY anywhere for this? I am a new GTO owner and want to make sure I do things the RIGHT way. Also, I assume a Pontiac / GM dealer would know that they would need to add Fm correct?


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## jpalamar (Jul 22, 2008)

symbian said:


> Does anyone have a DIY anywhere for this? I am a new GTO owner and want to make sure I do things the RIGHT way. Also, I assume a Pontiac / GM dealer would know that they would need to add Fm correct?


Don't take it to a dealer for this. It is easier then doing an oil change.

1. Remove fill plug. It is huge(like 30mm+ big). Mine also had an alumium tab with writing on it. I didn't have a socket that big so I used an adjustable wrench as it shouldn't too on there too tight.

2. Rebove the drain plug, very bottom bolt on the diff.

3. Let drain.

4. Install drang plug.

** Please make sure you check with the fluid manufacter to verify that it works with our diff and does or doesn't need FM. **

5. Fill until it oozes out. Then you know it is full.

6. Put fill bolt back on .


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## symbian (Aug 7, 2009)

jpalamar said:


> Don't take it to a dealer for this. It is easier then doing an oil change.
> 
> 1. Remove fill plug. It is huge(like 30mm+ big). Mine also had an alumium tab with writing on it. I didn't have a socket that big so I used an adjustable wrench as it shouldn't too on there too tight.
> 
> ...


What exactly fluid did you use? Did you add FM? Where do you buy it? Sorry for the newb questions but I want to get it right.


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## CChase (Dec 11, 2007)

Just use the GM with the FM in it if you want to do it right. Everything else is a gamble.


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## jpalamar (Jul 22, 2008)

symbian said:


> What exactly fluid did you use? Did you add FM? Where do you buy it? Sorry for the newb questions but I want to get it right.


I justed RP 75W-140. Bought it at Pep-Boys for $17.99 a quart. It already has FM in it.



http://www.royalpurple.com/gear-oil.html said:


> Max-Gear is an ultra-tough automotive gear oil. It’s designed to maximize power and provide unsurpassed protection to heavily loaded gears. It makes gears run smoother, quieter, cooler and longer without overhauls.
> 
> Max-Gear outperforms other gear oils because it combines the highest quality synthetic oils with Royal Purple’s proprietary Synslide additive technology.
> 
> Max-Gear is recommended for use in truck, motor home / RV, and automotive front or rear differentials, manual transmissions, and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary.


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## Cobra126 (Sep 24, 2009)

Anyone know the torque on the drain and fill plugs?

BTW....the Amsoil Severe Gear oil I used in my C5 DID have the FM already in it! Used it and that baby purred beautifully!


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## jpalamar (Jul 22, 2008)

Cobra126 said:


> Anyone know the torque on the drain and fill plugs?
> 
> BTW....the Amsoil Severe Gear oil I used in my C5 DID have the FM already in it! Used it and that baby purred beautifully!


I treated mine like an oil drain plug when i tightened them.


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## FastFrank (Jun 12, 2009)

Cobra126 said:


> Anyone know the torque on the drain and fill plugs?
> 
> BTW....the Amsoil Severe Gear oil I used in my C5 DID have the FM already in it! Used it and that baby purred beautifully!


Sorry, but you'll have to provide something more than your say so about this. The Amsoil website states that they do not provide a product for our diff's, and in fact recommend the GM stuff. Do you have anything to back up your claim? If the Severe Gear oil did contain FM, I don't see why Amsoil wouldn't recommend using that instead of telling us to use GM's products.


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## HP11 (Apr 11, 2009)

Cobra126 said:


> BTW....the Amsoil Severe Gear oil I used in my C5 DID have the FM already in it! Used it and that baby purred beautifully!


Not according to anything I could find anywhere on their website or on a bottle of Amsoil Severe Gear 75W-140 that I'm reading the label in front of me as I type this.....


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## Cobra126 (Sep 24, 2009)

I am talking about for my C5 Corvette I previously owned!, Not the GTO. But.... the Amsoil product I used in the Vett DID have the FM in it. Sorry for the confusion 

I just looked and still have the stuff on my shelf. It says nothing about having any additive in it, but when I was on the Vett forum and spoke to the sales rep at Amsoil, I was told that I will not need to add FM to it. I had it in there for about 25,000 miles and alway was fine. The bottle also says that if chatter occurs, use the Amsoil FM additive.


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## HP11 (Apr 11, 2009)

No confusion here. More like irrelevance or misinformation. This, not being a Vette forum makes the relevance of that quite suspect. That coupled with the fact that the product that you used couldn't have been 'Severe Gear' as is doesn't have that additive. Plus, it was *you* that said it had FM in it and that it was *you* that said you were told by an Amsoil rep that told you that you wouldn't need to add FM to it. Like I said, no coufusion here. At least, not on this end..........:cheers


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## GTOJer (Oct 20, 2006)

Here is what I have used before the Kazz:

This is from the RP website.

_Max-Gear is an ultra-tough automotive gear oil. It’s designed to maximize power and provide unsurpassed protection to heavily loaded gears. It makes gears run smoother, quieter, cooler and longer without overhauls.

Max-Gear outperforms other gear oils because it combines the highest quality synthetic oils with Royal Purple’s proprietary Synslide additive technology.

Max-Gear is recommended for use in truck, motor home / RV, and automotive front or rear differentials, manual transmissions, and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. *All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials*. No additional additives are necessary._

This made the rear end quiet and no chattering.


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## Cobra126 (Sep 24, 2009)

HP11 said:


> No confusion here. More like irrelevance or misinformation. This, not being a Vette forum makes the relevance of that quite suspect. That coupled with the fact that the product that you used couldn't have been 'Severe Gear' as is doesn't have that additive. Plus, it was *you* that said it had FM in it and that it was *you* that said you were told by an Amsoil rep that told you that you wouldn't need to add FM to it. Like I said, no coufusion here. At least, not on this end..........:cheers


Yeah I said it had the FM in it, cause I was told it! The point I am making is that I was told it did not need FM, and it didn't. Obviously whatever lubricants are in the severe gear are sufficient enough that the FM was not needed for my specific application. Anyway I am going with the RP!


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## HP11 (Apr 11, 2009)

You don't need to explain it to me......


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