XJ6 & XJ12 Series I, II & III 1968-1992

XJ Series 2 V12 - Tremec T56 Magnum 6 speed manual gearbox

Old Aug 24, 2024 | 03:50 AM
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Default XJ Series 2 V12 - Tremec T56 Magnum 6 speed manual gearbox

Hi - has any one fitted a Tremec T56 Magnum 6 speed manual gearbox to your XJ series 2 auto.

If so, does it fit with minimal modifications to the transmission tunnel and what other issues have you found after installation that are a concern.

Also did you change gearing so only 6th was O/d or did you stay with the standard gearing where 5th and 6th is are O/D gears.

Thanks

Garry
 
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Old Aug 24, 2024 | 12:24 PM
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Yes, I've done the only 6.0 v12 T56 magnum that I know of and a multitude of others. The earlier motors are a bit easier becasue the ignition isn't run off the flywheel. I can assist your on a consulting basis and you will have to sign a NDA. There is an expensive and slow way and there is a less elegant, but easier and lower cost way also. Both will offer excellent results from the drivers seat. PM me if interested.
 
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Old Aug 25, 2024 | 12:35 AM
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Thanks for the information that the T56 will fit a Series 2 - I appreciate there will be some mods but as long as it basically fits the tunnel without too many mods. I have access to to bellhousings, flywheels and clutch slave cylinders and can modify the standard Series 2 V12 auto brake pedal housing to suit a manual. the main issue was will it fit.

I can now go to my supplier with my spare engine and fit up the gearbox and clutch to the engine.

Thanks

Garry
 
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Old Aug 26, 2024 | 03:40 AM
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The conversion does not need an expensive adaptor. That is something you can do yourself in one easy morning. The “trick” is Jaguar made alignment easy because the alignment of a Chevy Bellhousing ( needed to bolt the transmission to the Jaguar block is already done ) The bolts only serve as a clamping force Ask I’ll walk you through the process.
 
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Old Aug 26, 2024 | 04:54 AM
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Thanks - adaptors are not needed as bell housings to match the V12 to the Tremec are available locally
 
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Old Aug 26, 2024 | 05:34 AM
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At what cost? Don’t you have to buy the whole kit? There is mark up on all those parts
Yes it’s one stop shopping and you don’t have to think.
I’m clearly too cheap to spend my money like that. I figure I’ve only got X amount and I’ll trade a little work for a savings enough to go racing.
It’s reasonable that might not be your priority.
 
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Old Aug 26, 2024 | 06:16 AM
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Sorry - there is no kit for this modification - the gearbox does not come with a bell housing, the auto one is of no use and a purpose made bellhousing for about $750 AUD is not much in the scheme of things. I will also need a manual flywheel - also about $750 AUD. I will also need to modify the auto pedal box to take a manual pedal and master cylinder which again is no big deal - just some drilling and fabrication. I have done all this with my E-Type V12 where I fitted a GM fitted Getrag 5 Speed gearbox so learnt a lot from that - some aspects were easy, and given what I have learnt, I would do others differently.

Cheers

Garry
 
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Old Aug 28, 2024 | 09:08 AM
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It would be the same kit as used in the XJS.
I hope you are aware both use the same basic chassis.
I had a brain fart forgetting the sedan never went to the GM Turbo 400 in the 3 rd quarter of 1977 like the XJS did. Not sure why.
When I raced a very early 1975XJS I used the earlier XKE bell housing to get a manual transmission
Since then I’ve always used the later engine and put on the earlier heads. ( flow a lot better than the HE and have the potential for a lot more power). Actually the 3rd quarter of 1977 until 1981. With the advent of the HE you get the best of both worlds. 1980 actually had 10:00-1 pistons in England( I assume Australia as well? Power for that engine was 299 DIN Net.
 
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Old Aug 30, 2024 | 08:03 PM
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Originally Posted by Garrycol
Sorry - there is no kit for this modification - the gearbox does not come with a bell housing, the auto one is of no use and a purpose made bellhousing for about $750 AUD is not much in the scheme of things. I will also need a manual flywheel - also about $750 AUD. I will also need to modify the auto pedal box to take a manual pedal and master cylinder which again is no big deal - just some drilling and fabrication. I have done all this with my E-Type V12 where I fitted a GM fitted Getrag 5 Speed gearbox so learnt a lot from that - some aspects were easy, and given what I have learnt, I would do others differently.

Cheers

Garry
the simple low cost way is get the Chevy V8 bell housing and make the adaptor. Tilton makes one that confirms to racing rules for safety. Or just any Chevy bell housing from 1955 to very recent.
 
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Old Sep 21, 2024 | 01:40 AM
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Originally Posted by Mguar
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The conversion does not need an expensive adaptor. That is something you can do yourself in one easy morning. The “trick” is Jaguar made alignment easy because the alignment of a Chevy Bellhousing ( needed to bolt the transmission to the Jaguar block is already done ) The bolts only serve as a clamping force Ask I’ll walk you through the process.
Thank you, that helps a lot. You saved my day.
 
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