Rear end fluid
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From: LeClaire Iowa
Rear end fluid
I just had a shop change my diff fluid on 96 coupe. I told them it needed the additive. They changed the fluid and used a synthetic that claims it has the limited slip additive already in it. I did a search and everybody says to put one bottle of additive in anyway. My question: Since I have never had this type of rear end what would my symptoms be if I need to suck 4oz out and add a bottle. Thank You Dan
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I just had a shop change my diff fluid on 96 coupe. I told them it needed the additive. They changed the fluid and used a synthetic that claims it has the limited slip additive already in it. I did a search and everybody says to put one bottle of additive in anyway. My question: Since I have never had this type of rear end what would my symptoms be if I need to suck 4oz out and add a bottle. Thank You Dan
What brand & weight did they use? Perhaps someone has used the same and can mention either a good or bad experience!
Last edited by WVZR-1; Apr 24, 2017 at 05:48 PM.
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according to this, you need an additive for limited slip - BG LSII, PN 328 at a 10% ratio.
personally, I'd add in 4oz of the GM additive, however, FWIW, the FSM specifies 80W-90 GL-5 gear lube w/ limited slip additive - not 75W-140.
Last edited by Joe C; Apr 24, 2017 at 07:22 PM.
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From: LeClaire Iowa
Thank you . I will print this off and take to the shop. Dan
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What most people/your shop don't understand is that gear lube is for use in limited slip differentials AFTER you add the limited slip additive.
I just drained and refilled my 86 C4s diff last month with cheap Valvoline 80w90 GL-5 gear lube ($6 a bottle) and 4oz limited slip additive and my 31 year old diff is as quiet as a mouse and fried the both tires when i laid into it.
The only gear lube I'm aware of that you don't add limited slip additive is Royal Purple.
I just drained and refilled my 86 C4s diff last month with cheap Valvoline 80w90 GL-5 gear lube ($6 a bottle) and 4oz limited slip additive and my 31 year old diff is as quiet as a mouse and fried the both tires when i laid into it.
The only gear lube I'm aware of that you don't add limited slip additive is Royal Purple.
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From: Ashland, OH
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I'd say MAYBE - you don't know for a fact what they put there so let them explain and comment. BG does have a product 751 that would maybe have been more appropriate, maybe that's what they used and their "invoicing" does the single feature on the ticket. That would seem ODD but who knows.
There's nothing in the specification that's been posted that it's an accepted product for the use BUT if they show you otherwise then ......
It's worth a conversation!! SHOW ME I guess works. Is their an application guide by vehicle that they use and can show you?
I'd think this is more appropriate product and also the additive:
https://www.bgprod.com/catalog/drive.../#bg-product-1
What was the charge for the differential service?
Last edited by WVZR-1; Apr 25, 2017 at 09:26 AM.
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From: Ashland, OH
Thread Starter
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From: LeClaire Iowa
Thank You all very much. I will pull it out and replace with the correct fluid and the additive. Too much doubt in my mind now. To answer a question from a few posts ago the cost was $99.00. I sure wish it had a drain plug. I am aware it can be added. Dan
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If they're going to "up-sell" and provide quality/correct service that's one thing - the "up-sell" and use something other than just shouldn't be done. I'd be looking for some $$'s and maybe a correction.
Did you have them perform other services at the same time and were BG product used for those services?
What do they have to offer for correct product? I'd ask!!
Last edited by WVZR-1; Apr 25, 2017 at 11:29 AM.
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). at that price, (and for as often as you'll service the rear end), they're damn near disposable. I've used them, and they work great. as a matter of fact, I always keep a couple around the shop. for $100, i'd be spending a half-hour or so under the car, and do it myself. that way, at least you know it's right. 
the same pump sells elsewhere for $12-15.
Last edited by Joe C; Apr 25, 2017 at 12:07 PM.