I have searched and searched and have tons of info but am a little confused on all that needs to happen. As far as the links below have led me to believe, I can use regular Dana 44 gears (of the appropriate carrier height) with a GM input to basically bolt in a higher ratio. It seems that other than the spline count, the parts are interchangable except the larger diameter bolt holes in the Jag parts.

https://www.jaguarforums.com/forum/x...d-68571/page9/

https://www.jaguarforums.com/forum/x...f-59936/page2/

https://www.jaguarforums.com/forum/x...e-diff-163049/

Dana 44 into a 19 spline Salisbury Jaguar IRS conversion parts. | phrog

Jaguar Differential Build

https://www.jaguarforums.com/forum/x...l-86527/page2/

 

I assume you are trying to increase the spline count for a taller ratio ? I Looked at this before as I would like to do myself . I don't see it possible without increasing the housing size for a larger diameter gear while maintaining proper gear intermesh surface which is very critical . Is yours the 3.58 ?

 

Some of those links are to different types of differential. There is a earlier kind that was used on the first style IRS, and the later than was used on the XJ40, X300 etc.

Some parts are interchangeable, most are not. The carriers and power lock components are quite different for example. Apparently the Dana rings gears are fittable onto the first style differential, with the modifications you mentioned.

However, lets back up a step: what do you have and what do you want to do?

 

I have a stock 3.27 Powerloc in my 95 XJR. I want steeper gears. Richmond Gears states that the regular D44 gears for the 3.73 (short) carrier and down will work on the x300.

I have already ordered a ring and pinion and the GM input that were discussed in a few of the links I posted.

Mainly, I wanted to see if anyone had done a regearing. I have parts coming and the diff is coming out in the next week.

 

I have rebuilt one in an XJS, but not changed the ratio. The standard XJ6 and VDP are a 3.58 ratio, others were available. I changed my whole diff to a 3.77 (from 3.58), just because that's what I could get with limited slip. Performance wasn't noticeably improved ( except in winter, where the limited slip made a big difference) and it cost me about 2 mpg in highway cruising mileage.

Looks like only the 3.27 and 4.09 gears are still available from Jaguar.

 

Do you remember the source if outside Jaguar ?

 

I was looking at Jaguar Classic parts, the heritage division of Jaguar. I believe Sailsbury made the diffs for Jaguar in the UK, but I have no idea if they sell parts retail - I doubt it.

Part number for the 4.09 gears is JLM1685, showing a price of £384.99

 

Found it , will have to set out another piggy bank

https://www.jaguarclassicparts.com/uk/part/JLM1685

Thanks , Parker

 

If this all works out I will post what I did to make it happen.

 

I'd be very interested to know how it goes. Last winter I took 3 diffs apart to use parts to make 1, but I used all Jaguar parts.