Need help ASAP: Does Mobil 1 diff oil need the friction modifier?

[keeksv]

Originally Posted by trukk

My Clutch packs are binding, when I go around low speed corners. It'
s really loud. This just started about 1000 miles after this fluid change. WTF?

-Chris

Sorry Chris. Get the fluid swapped out to GM fluid and see if that helps, but I fear the worst. Did you check your fluid level?

One of the fixes for this problem with Trailblazer SS and Corvette I think was to add twice the amount of friction modifier with a fluid swap (so I wouldn't worry about anything you did with too much additive), but in the case of the TBSS at least, most people ended up having to have the center section of the rear replaced.

[trukk]

Originally Posted by ewill3rd

Chris, when are you coming back in?

I am busier than even I can believe right now but you know we'll work you in when you are ready

I'ver also been crazy busy. I need to get it in. I was hoping to kill a bunch of birds with one stone on this one. I'd like to address this issue, take car of the racla for the pinion seal, and have the Gm Racing Control arms installed all at the same time (to hopefully save on some of the labor cost.) Can you guys do the pinion seal replacement yet? it just doesn't seem to make sense to not do this at the same time.

Originally Posted by keeksv

Sorry Chris. Get the fluid swapped out to GM fluid and see if that helps, but I fear the worst. Did you check your fluid level?

One of the fixes for this problem with Trailblazer SS and Corvette I think was to add twice the amount of friction modifier with a fluid swap (so I wouldn't worry about anything you did with too much additive), but in the case of the TBSS at least, most people ended up having to have the center section of the rear replaced.

I haven't checked the fluid level. I wouldn't think that was the issue, since Bill changed the oil.

-Chris

[keeksv]

I'm sure Bill filled it, but did it stay in the diff? That's what I meant. Maybe you do need the pinion seal thing done not just as a preventative measure.

[ewill3rd]

I am not sure if I have any in stock, but we are installing the updated pinion seal for leaks under a new service bulletin that came out last month.
I am confident it will be the same as the recall parts, but the recall is not out yet.
I am sure if you see a leak of any kind I can do the seal, I like to drain and refill the diff when I do that. You want to try doing it with no friction modifier?
It doesn't matter whether we do the control arms or not at the same time except the exhaust only has to come off once.

For the love of God don't come in tomorrow!
I am on the verge of catching up but I am about 6 cars deep right now, including Rob's car.
He is itching to get back to Florida but I found a cracked control arm bushing and I can't get the replacement one until tomorrow.
I was hoping to have him done today but he's gotta stay one more day and I have a bunch to do to get him back on the road as early as I can tomorrow.
Plus I have a couple more V's and an XLR-V in here and a nice lady with a Deville that has been waiting on my since Monday... and two more jobs that came in today!

Ack! I need another helper and 2 more lifts.

[trukk]

Originally Posted by keeksv

I'm sure Bill filled it, but did it stay in the diff? That's what I meant. Maybe you do need the pinion seal thing done not just as a preventative measure.

I haven;t noticed any spotting on my driveway, so I don't think it's leaked. after the track day, I was under the car extensivly, and didn't see any leaks. Also Bill was under there, when I brought the car back after the track weekend, due to my looose toe bolt, and he didn't comment on anything looking leaky (I was also in the bay with him for about 15 minutes, looking under the car while it was up, and again so no signs of a leak).

-Chris

[ewill3rd]

I don't remember seeing any leaks, make sure to put it on the next list and I'll check it while I am working on it.
As mentioned if I see a leak we'll go after it with all we got.
I was more concerned about that funky self adjusting toe issue.
Man that was such a freaky feeling.
Glad we got that fixed!

[C66 Racing]

Originally Posted by keeksv

One of the fixes for this problem with Trailblazer SS and Corvette I think was to add twice the amount of friction modifier with a fluid swap (so I wouldn't worry about anything you did with too much additive), but in the case of the TBSS at least, most people ended up having to have the center section of the rear replaced.

However, many posters on the Corvette Forums are reporting the diff chatter also goes away when using two quarts of the AMSOIL Severe Gear 75w90 and one bottle of the AMSOIL Slip Lock Additive. For some reason, the AMSOIL fluid appears to have different friction characteristics that appear to work better with the diff's GM has been using in the last couple of years.

For those who are interested, AMSOIL recently released a very comprehensive gear lube test that included both the factory GM diff fluid as well as the Mobil 1 that started this thread:
AMSOIL Gear Lube “White Paper” (481 KB pdf file)

[ewill3rd]

You guys made me go look.

I found a new bulletin from GM that came out YESTERDAY.

I have been talking to the Brand Quality Manager for XLR for about a year on the diff chatter problem.
He said GM is coming out with a new LS fluid, it looks like it is available, which reminds me I have an XLR customer to notify!
At any rate, maybe this would be good for the V? I can call him and ask him if he has heard anything regarding this issue on the D car and see what he says if you guys want to know.

Chris, let me know if you want to try this stuff instead of what is in there or the old GM fluid.
I'd have to order some.

[ewill3rd]

The new LS fluid is out, I have some ordered.
I asked a guy at GM if it has been used to correct this issue in CTS-V, he said it was being "validated" for other carlines.
I am sure it will help.
I am almost caught up Chris.
I have to go take my VA inspector test today at lunch though, hope I pass