: Diff lube?



ronr
06-11-06, 05:13 PM
The FAQ site has part number 89021677 as the lube for our diff's. The dealership put 89021671 into mine last week and I didn't see the friction additive on the reciept (picked the car up after hours on Friday so I couldn't talk to anyone and they're not in on the weekend).

Does anyone know if the 71 p/n is a new lube to replace the 77 or is it just the wrong stuff? Also, does it require friction modifier like the 71 did?

ewill3rd
06-11-06, 09:18 PM
Should be 1677 if you are in the US.
Not sure what that other part number is. From recent experience what I'd do is go the parts department and get them to let you put your hands on a bottle.
Read the back. Make sure it meets GL-5 specifications.
If it says "GL-4" on the back ask them why they just ruined your rear end.
Many techs don't even understand the difference between GL-4 and GL-5 fluids. Many moons ago they came out with GL-5 for hypoid cut gears. Hypoid gears have much higher pressure requirements and a GL-4 fluid in a hypoid cut rear will cause premature failure of the gearset due to wear damage.

If it says GL-5 ask them why they didn't install the friction modifier.

If it says it's GL-5 with the modifier already mixed in, tell them thanks and go home. ;)

I don't have any data on that part number specifically. My preliminary google search shows that to be a GL-4 fluid.

The manual does not specify GL-5, but it should.
GL-4 is designed for a "straight cut" gearset. More google searching will help illustrate the difference between a straight cut gear and a hypoid gear.

patentguy
06-11-06, 09:21 PM
Is replacement of GL-5 one way to get rid of the whine?

rand49er
06-11-06, 11:14 PM
Well, Ron, this might have a silver lining to it: a new dif paid for by your dealer !!! :highfive:

ronr
06-12-06, 09:40 AM
Well, Ron, this might have a silver lining to it: a new dif paid for by your dealer !!! :highfive:
Unfortunately it's a new diff that they put it into :crybaby:

I called them this morning to check things out.

ewill3rd
06-12-06, 09:59 AM
Everything coming off the factory should have GL-5 fluid in it.
It's a specification just like you'd find on a bottle of engine oil or ATF.
Always check the specification for your application.

The problem you run into is people overbuy lubricants. Specifications change rapidly and the new fluids are backward compatible but the old stuff is not forward compatible. Places try to use up old stock by putting it in cars that it doesn't meet the specification for... then you have problems.
I can't guarantee that running GL-4 for a short time will permanently damage the rear axle but I would definitely have them change it if that's GL-4 fluid.
It won't last too long with the wrong stuff in it.
It won't hurt the bearings nor should it hurt the spider gears but it will wipe the faces off the ring and pinion if left soaking in GL-4 fluid.

As an example your engine oil is designed to meet a GM testing specification of GM4718M. That should be on the back of any bottle of oil you put in your car. If it's not then you could potentially cause engine damage.
On a non-synth car you'd be looking at a GM6094 specification.
The API starburst on the front of the bottle has the specs for engine oil as well.... usually.
You can research this kind of stuff pretty well with google.
Search for API starburst and you'll see what I mean about oil specs.

Good luck.

SBONES
06-12-06, 11:03 AM
it might be in there...it just may be how the service writer wrote it.

ronr
06-21-06, 02:13 PM
Does anyone know where I can get a GM document that says the rear is a limited slip and/or that it needs the friction modifier. The RPO codes for the '04's don't call out the diff as limited slip and the owners manual as well as the service manuals don't say anything about it needing the friction modifier.

The Tony Show
06-21-06, 02:48 PM
I just walked back to my Parts dept. and checked the GL-5 axle lube, and the PN ended in 21669. Perhaps a newer part #?

I hope so, because that's what they put in my new diff about a month ago.....

ewill3rd
06-21-06, 03:44 PM
I know of a bulletin for chatter but I haven't seen a specification that says it requires it.
The V has a limited slip rear, as you guys know.
Does yours show a G80 RPO on the decal? (spare tire cover)

ronr
06-21-06, 04:26 PM
I know of a bulletin for chatter but I haven't seen a specification that says it requires it.
The V has a limited slip rear, as you guys know.
Does yours show a G80 RPO on the decal? (spare tire cover)
I'm not sure since it's at the dealer but I'll give them a call. Does the G80 RPO referenced the limited slip differential?

I've come to realize that the tech at the dealership has a real chip on his shoulder now because I proved him wrong regarding the correct lube so he's going to require extreme proof that the friction modifier is needed before he admits being wrong again. The service manual says the friction modifier is needed if it's a limited slip but there is nothing confirming it's a limited slip and the owners manual makes no reference to the friction modifier being needed. :rant2: Thankfully I've got a service writer who's as upset with the tech as I am (if not more so).

StealthV
06-21-06, 05:57 PM
Aye G80.

http://www.cadillacfaq.com/faq/answers/rpocodes.html

ronr
06-21-06, 06:05 PM
That should be all I need. I'll let you know how it turns out :)

rand49er
06-21-06, 06:06 PM
Does anyone know where I can get a GM document that says the rear is a limited slip and/or that it needs the friction modifier. The RPO codes for the '04's don't call out the diff as limited slip and the owners manual as well as the service manuals don't say anything about it needing the friction modifier.Ron: On page 6-13 of my owner manual it says "SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 12378261 ...) ... and add 4 ounces (118 ml) of Limited-Slip Axle Lubricant Additive (GM Part No. U.S. 1052358 ...) ...", but it does not say explicitly that the V has the lim-slp dif ... unless it says it somewhere else in the manual. Hope that is of some help.

ronr
06-21-06, 06:14 PM
Ron: On page 6-13 of my owner manual it says "SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 12378261 ...) ... and add 4 ounces (118 ml) of Limited-Slip Axle Lubricant Additive (GM Part No. U.S. 1052358 ...) ...", but it does not say explicitly that the V has the lim-slp dif ... unless it says it somewhere else in the manual. Hope that is of some help.
Thanks Randy, unfortunately that was an add to the manual in '05 and my '04 maunal doesn't make reference to the additive. Of course I now have an '06 diff under the car but my friend the technician doesn't seem to think that matters.

We're down to a battle of wills :mad: and this guy hasn't figured out that I'm a red head of German descent backed by 2 engineering degrees from GMI (General Motors Institute) and a great community of folks on this forum! :)

rand49er
06-21-06, 07:45 PM
... I'm a red head of German descent backed by ... a great community of folks on this forum! :)And, he doesn't drink, folks !?!

I have two (and a half) degrees from the Univ of Mich ... maybe that's why I do. :alchi:

ewill3rd
06-22-06, 08:47 AM
Tell him to refer to this document:

PIP3152G

Also refer to
Document ID# 1702638
That document is the lubrication specification document that clearly states for a limited slip differential:


Lubrication Specifications
Capacities Application
Quantity

Metric
English

Differential Lubricant GL 75W90 G/M P/N 12378261 (Canadian P/N 10953455)

Drain and Fill with cover removed.
1.2 L
1.27 Qt

Drain and Fill with use of drain plug.
1.0 L
1.06 Qt

Important: The Limited Slip Additive container capacity is greater than the amount needed. Only add the specified amount.

Limited Slip Differential Lubricant Additive GM P/N 1052358 (Canadian P/N 992694)

Drain and Fill with cover removed.
100 ml
3.38 oz

Drain and Fill with use of drain plug.
70 ml
2.37 oz



BTW, I don't think the G80 RPO will show on the SPID label but anyone with a pulse and 3 firing neurons in their brain should realize that a CTS-V has a limited slip rear diff.

ronr
06-23-06, 09:28 AM
Thanks for everyone's help...I won! Friction modifier and new lube in, car being delivered to my home later today.