Hi. The auto box on my 1968 420 is faulty. I can acquire an auto box from a later model XJ6 4.2L which apparently has overdrive. Not sure at this stage which Borg Warner it is. Is this a direct bolt-on? Any pitfalls?

 

What year XJ6 ? The XJ auto box will be a Borg Warner, but the XJ was in production for so long, the gearboxes changed as BW developed things. So it might bolt straight on if it's an early XJ, but for later cars it needs careful checking.

 

Thx Fraser. Its apparently a 70's XJ6 Executive and it has the overdrive facility which is what bugs me. Im not sure how compatible it will be. I am finding out the exact year model. Should I be looking for a BW Model 8 exclusively?

 

AFAIK, no auto gearbox on a Jaguar ever had an overdrive facility. Overdrive was, of course, common on British manual gearbox cars in the 60s and 70s. These were made by Laycock de Normanville company. SO it sounds as if your suggested gearbox is a manual one.

According to Paul Skilleter's encyclopedic book on Jaguar saloons, the early 4.2 litre XJs had the BW Model 8 autobox then in 1970, the Model 12 was fitted. The Series 3 saloons started with the BW 65, then later it was the 66.

 

Ok so they XJ6 gearbox is definitely off the table. Most agree its not an option. My next challenge is that most macs seem to think its a BW 66 which will be good news cos Model 8 parts not available here at all. Where can I reference the box versus the Vin number? Or how do I identify it?

 

if you take it out, shops charge a lot less to rebuild them. I had a DG65 done for $250 and a XJS turbo 400 done for $400.

 

Thank you all for your help!! Incredibly there was an airlock in the box that prohibited oil circulation. We added a pint of oil and relieved the airlock and that gearbox kicked in decently! No swop happening thankfully!

Again, thank you all for your fantastic help!