synth in a posi rear

So I'm pissed off and want to solicit your comments and experiences.

My Mom rocks a 96 Camaro RS that looks showroom with 60K on it.

Highly optioned with a 3.42 Posi rear (just ran compnine on it).



She took it in for an oil change today and the aholes at Tire Plus told her the rear diff was dry, she worried and told them to fix it (I won't go into the other 4 services she declined and doesn't need). Anyway the receipt she read me said they used "Gear Glide Synthetic". No mention of a posi additive on the receipt. They whacked her for $200 for a new diff gasket and the 90W synthetic.



After a quick google, I could not find a manufacturer for "Gear Glide Synthetic gear oil", and found references on the Corvette forum that say synthetics and factory eatons don't mix well.....



Opinions and experiences please..... I told my Mom to call tomorrow and demand they swap back to Dino juice and GM additive for the rear at no charge to her, since they screwed up trying to screw her, as I doubt the rear was dry as she said there was no noise at all in the back of the car.

I can say that I personally have not had good luck with pure Synth gear oil in my stock posi units. Did that once in my old '95 AGW and that thing made noise once it got good and hot. Changed the fluid to the reg stuff and no issues at all.

Now for the OCC...(has factory posi) I used the Valvoline Dura Blend (cause I got a good deal on it) and have not had any issues for 14k miles. Its a mix, not pure Synth. I put the same stuff back in (and another bottle of additive) when I did the pinion seal swap too.

http://www.valvoline.com/products/brands/durablend/gear-oil/62

Have a look under the car. I'll bet ten that the diff cover never came off

jayoldschool wrote:

Have a look under the car. I'll bet ten that the diff cover never came off

I hear you there, I told her NOT to take it back tomorrow until I can look at it, so I suspect that is the case. So then I REALLY will be pissed

Man that would suck...but Jay has a point...

I am with Jay on this one besides I bet at most they probably threw a little gear oil on the cover to make it look like they worked on it.
IMHO
Jim Gordon

Ouch. We have those tires plus places up here. Ripoff artists to the extreme. Hope you get this worked out for your mom.

There's a really good thread over on the Garage Journal right now about the quick lube places. Some "interesting" stories...

jayoldschool wrote:

There's a really good thread over on the Garage Journal right now about the quick lube places. Some "interesting" stories...

I didn't get over to my Mom's today, but she called them and they toldher the additive was in the lube they used..... I wrote the info down but left it on my desk at work. Will investigate tomorrow and see if there is a new gasket on the diff.

Jay I should take your ten
I didn't even pull the jack out of my wagon, the gasket was fresh.
I did notice on the floor of Mum's garage, evidence of drippings but nothing that would have been considered a dry unit type of leak (car spends more time in garage then on the street).

So......was it leaking? Yeah but a drip every couple of days type of thing.

I ran compnine on it and noticed, not only did it have a G80, but also 3.42 rear. I've driven the car several times in the past, but not like today.

Research told me if I got on it hard and the oil/additive wasn't doing it's job, it'd chatter and you could feel/hear it.

ROAD TEST!

I stomped it pulling out of my Mom's development and to my surprise on very dry pavement that 3800 spun both rear wheels sporting pretty fat rubber. Car slid out into the second lane with the arse hanging out and the posi did it's thing and put it all where it was supposed to be. Heyyyyyyyyyy this little motor puts it down. The car is optioned out and I did notice on compnine sumthin' about performance pkg on the engine.

I was pleasantly surprised that I could slide it around corners with ease on dry pavement, and even got posi axle hop on one turn so I knew it was all good. All was quiet in the rear so I'd say while they overcharged her for the work, they did what they were supposed too.

Glad it worked out! And yep I really like those 3800's. Running little motors!

Glad to lose this bet. Cold one on me next time I see you!

jayoldschool wrote:

Glad to lose this bet. Cold one on me next time I see you!

Look forward to it.......hmmm saw there is a supercharger avail for this motor .....

i have a new eaton posi still in box the directions say not to use Synthetic

Sprocket wrote:

jayoldschool wrote:

Glad to lose this bet. Cold one on me next time I see you!

Look forward to it.......hmmm saw there is a supercharger avail for this motor .....

Have the needed M90 sitting on my shelf. Needs a bearing and coupler kit and you'll need the intake, injectors etc. Don't think the blower 6.5 is ever going to happen

Bill