Oil for the differential

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Richard Bieling

Jun 17, 2021, 5:59:33 PMJun 17
to AuroraCobra
Greetings all, 
I just purchased an aurora cobra #81. It has been sitting for about 16 years and I would like to change all the fluids.
It was in a garage, not a barn find and is in pretty good shape. It has about 14,362 miles on it.

What oil do you recommend for the differential?

 I am going with a 80-90w weight GL4 for the top loader transmission.
Also I have the original rims for sale. the 5 bolt rears and the four bolt fronts.

Thanks again,

pet deg

Jun 17, 2021, 9:51:13 PMJun 17
to auror...@googlegroups.com
I'm pretty sure I just used the GL-4 in diff last time but I'll check tomorrow . In the meantime, how about posting some pictures of your find ? cockpit / engine / and car itself . If you don't mind me asking, where did you find it ? and where do you live ? and the big question is how much ? 

You will find a lot of guys here that will help you out, as well as all the info that has been posted on fixes and improvements.

Peter # 78

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Subject: [auroracobra] Oil for the differential
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Robert Young

Jun 18, 2021, 9:22:13 AMJun 18
to pet...@hotmail.com, auror...@googlegroups.com
Hi Peter.....you took the words out of my mouth with your questions regarding Rich's new ride - looking forward to more info and pictures of his LOW mileage Cobra, along with a bit of it's past history. I am sure that some of the members will provide him with all the information he needs regarding his new purchase. It reminds me that I also need to update my pics of #087 but still a work in progress. Bob

the web guy

Jun 18, 2021, 12:13:19 PMJun 18
to AuroraCobra
I’m happy to put up your photos on the site when you’re ready. As a shameless photography director, I always recommend crouching low with the camera at least 30’ from the car to prevent distortion. Zoom in so the car fills the frame. Low resolution is fine.

Richard Bieling

Jun 19, 2021, 1:05:32 AMJun 19
to auror...@googlegroups.com
I live in Weston Colorado.
A friend was doing work at the prior owners house and saw that he had a Triumph TR6. I am an owner of a 1976 Tr6 and while talking about his TR6 he noticed the cobra in the corner.

He told me about it and the rest is history.

I will work on a few more pictures and send it to you all as soon as I can.

The seat has a bit of wear on them and should be replaced.
The mice chewed a bit of the carpeting about  3 inch circle section on the passenger side floor

It has the mustang II front end to accommodate the 5 bolt wheels..

It starts right up and we will see how the car moves once I verify the brakes are good.

But here is a start.



pet deg

Jun 19, 2021, 1:38:42 PMJun 19
to auror...@googlegroups.com

Couldn't really remember what brand oil I used but I know it was an 85-140 mineral oil with a Posi additive , Now first make sure which rear end you have, yours should be at # 81 the Jag rear end but your close to switchover and might be a corvette rear-end.
Some guys use 75-90 but make sure to add or get Posi additive.

You tube has good videos of both differentials if you're not sure which one you have. Make sure you get the owner's manuals from Tom for both the GRX and Mark 2 a bunch of info in them.

Here's a jag site , but really any good brand ( Lucus / Valvoline etc. ) is fine. I wouldn't bother with the synthetics but that is up to you . 

Library Article: Inspection and maintenance, oil refilling procedure on rear suspension differential, LSD identification on the Jaguar XJ6 Series III. at The Jaguar Experience

Sent: Friday, June 18, 2021 9:51 PM
To: auror...@googlegroups.com <auror...@googlegroups.com>
Subject: Re: [auroracobra] Oil for the differential

Richard Bieling

Jun 30, 2021, 1:19:43 AMJun 30
to auror...@googlegroups.com
Thanks to all for the responses, greatly appreciated!

I have an LSD jaguar rear end, ( that did not sound right)  the car is listed as a GRX from the original sales title, as well as the GRX complete manual that came with the car.
I will get the 75-90 and add the posi additive.

The tranny will get the 80-90 GL4 treatment as soon as I get the oil delivered this week.
Once a few checks are complete I will take it for a ride and post a few more pictures. 

Thanks again

Someone asked what I paid for it, my reply was is a little less than I thought I was going to have to pay. Not sure what the range is for a pretty nice car, but maybe some of you would have an idea.

What information on this car is:

Charles Hillard Ford, Fort Worth Tx. bought the car in 09/11/81 ( used the car in the sales room for photo shoots with customers, painted it black at that time form the original yellow. ( there is a little yellow in the engine bay and it is a color I would not have picked ).

Russ Janeake purchased in 10/01/90 with 5814 actual mileage

T. Brooks purchased in 3/02/82  6451 actual mileage

F. Wendelken purchased ( Colorado) 7/11/98 11,965 actual mileage

Then Rich Bieling ( CO). 14,362 actual mileage, Last time it was registered from F. Wendelken was in 2008. the car just sat at 8000k feet above sea level at his house in Colorado. ( occasionally fired up but not driven, as the roads were not good).

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