1966 420 compact all synchro transmission, use it or not?

I’m buying some parts from a guy and getting a 4 speed synchro transmission with bellhousing and flywheel with some parts I want to keep. I’m building my Mk2 with a T5, so don’t need this transmission. It’s out of a 1966 420. I’ll put a listing up after I get it.

Definitely worth something in my opinion. Is it overdrive equipped? Even better if it is. It’s the same transmission as used in the Series 1 XJ6. .

It’s not overdrive. I’ll open it up and take a look. May even try a bench test to get an initial check of bearings for obvious noises and synchro condition.

These are sort of rare. At least around here. Certainly not worthless! They have a short tail (not no tail as in the e type) and a long cover right? An overdrive should be worth more for the obvious reasons…

Well here it is. Someone cut above the starter bendix bump, but otherwise very nice. I need the clutch fork, if its the same as a 3.8. I’m planning on draining the oil later. Last photo is stuff I absolutely do not need.




Oh right, it has the short cover, so it will be interesting for the E Type people but not for the XJ people.

The starter is a M100, later and lighter than what should have been in there, a M45G. Some see it as being better (because it’s lighter).

The alternator etc. is the same as in the XJ6.

Would it be the same as a later Mk2 or 340 sedan? Other than the bellhousing.

I do not know, and shouldn’t the bellhousing fit these as well/ why not?
Maaaybe the mk2 has a much longer tail.

It looks to be about the same length as the moss overdrive gearboxes I got rid of. I had a rough 340 project years ago that was a 4 speed and thinking back it was similar looking transmission. If it would fit I may want to hold onto it, even though I have no driveshaft that would work.

More info… it seems shorter than the moss OD that I had. I peeked in the fill hole with my inspection camera and what I saw looks great! Filled it with oil and spun it with a drill and ran it through the gears. Synchros grabbed well and it operated smooth and quiet.

I’m thinking of using this in my mk2, if I can come up with a driveshaft or reasonably come up with making one. I have a T5 set-up but like the idea of using the Jag unit. I drove a few vehicles that use the T5 and not crazy about the feel of the shifts, plus the long throws. Am I crazy??

The Torqutrol Viscous Coupler is a rare and sought after item for 4.2 MKX, 420G owners especially, as no other known VC will fit in the ridiculously small space of ~65mm.

The later Jag items are too close to the radiator, some electrics fit, but usually need shroud mods

They have not been available new for many years to the best of my knowledge

Unfortunately the fluid seems like it can drain out eventually, they should resist a bit, not spin freely, and have no notchiness whatsoever when rotated by hand

It was also fitted in 420, and early S1 XJ6

I’m sure it had some resistance and check this evening.

BTW most of the parts are in the trader section.

That’s what I would do Tim. I have this tranny with overdrive in one of my S1 XJ’s (Only difference is the top cover shifter position) it’s a perfectly good manual box… Although I will say I worked on and drove a customer’s Mk2 with a T5 conversion and I liked that as well. Also alot easier to change a clutch with a T5 because the box will separate from the bellhousing externally.

I will likely keep both, unless someone really needs the 4 speed.