The 'E' Type Forum

Looking for some advice here guys. I have a 2+2 s1 that I’m looking to swap out the gearbox for an OD unit or 5 speed. I’ve got the option to buy a 5 speed manual or OD late xj6 box (fuel injection car) but don’t have a clue which is better or which would fit without any hassle? Any help would be gratefully received.. thanks Paul

What is the 5 speed box from.........the xj6 with compact overdrive has been fitted by many to a 2+2 its more or less a straight drop in...a little fettling may be required around the speedo angle drive......you will need the top cover from a E tyoe gearbox or the gear lever will be in the wrong position.....Steve.....ps search 5 speed options or overdrive there is lots of info here on the forum.....edit...im assuming the 5 speed is xj6 Lt77 gearbox...search here for Lt77......not really an option....

Thank you, the box is from a late series 3 injection xj6. Sounds like the OD box is the one to go for ..?

Yes so long as its a compact A overdrive....Steve

Thanks Steve, now you are I am afraid dealing with an amateur here when it comes to boxes. The guy tells me indeed it is the OD compact A gbox, can you tell by looking or maybe a number?
Thanks so much

This is a 4 syncro gearbox with a compact A overdrive.....

Couldn’t be more helpful thanks so much Steve

Here is a photo of the S3 XJ6 5 speed (with engine) The remote linkage is not on the box. The LT77 was used in Land Rovers too (as you may know) There is a selection of linkages that can be modified to fit - several on here have done the conversion and may give us a few photos -

Barrie

Hi Barrie...dont know of anyone that has fitted the Lt77 into a manual 2+2....Skiday a member here fitted one into an auto 2+2 with the larger tunnel......also dont think you can change the gear lever position on the Lt77 box so it will be further back than a standard E type....Steve

Hello Steve, been told a bit of lateral thinking with the linkage is what is required - haven't done it myself so cannot comment further.

Barrie

Just musing on the LT77, we sold any we could get hold of in the 80's and 90's specifically for E-type conversions - wonder where they have all gone?

Barrie

The LT77 was widely used so there are varieties of linkages available. Rover SD1 , Triumph TR7 5 speed, XJ6 S3 ( probably more common in 3.4 litre versions ) , LR, Sherpa!!-( but the ratios are not suitable on the Sherpa box ) . However, I think the OD box is more suitable because the LT77 was prone to a very sticky/baulky gearchange when cold which often could only be alleviated by using ATF instead of gear oil, and I have a feeling the OD dimensions are more suitable

I’ve just relieved my S3 OTS of its heart, it’s had an O/D box on for some time now done by it’s PO. It’s very good and hasn’t given any problems. I believe the PO had a propshaft made to measure by Dave MAC in Coventry.
It’s currently on its stand, your welcome to come see if you,want. The current project is a rotisserie of a slightly different design.!!!

More of the same...

And if’s any help..

If anyone is contemplating a 2+2 5 speed lt77 conversion on a manual car there is a you tube channel called " EDSHED " restorations - where an unsuspecting S2 2+2 is (quite crudely) patched up and made ready for the road. Its not for the faint of heart - but is entertaining in parts !

Regards Barrie
The guy concerned -Ed - I remember him around 30 years ago at various Jag meets with a battered 3.8 early roadster - which he still owns amazingly - and its still battered and rusty but looks pretty much the same as I saw it then.

A key issue with the XJ6 5-speed is that although they usually come with the bell housing attached, not many come with the necessary Jag flywheel, starter, clutch and release bearing which are also hard to get. Having box and bell is the easy bit, so if considering the kit make sure it’s all there. The trans mount is also LT77 specific I believe.

If converting an auto, the gear stick should come out in the same place as the 4-synchro XJ box (with or without OD) - namely, in about the same place as the automatic gear selector on E-types, which is on the sloping part of the console and works very well. Converting a manual 2+2 to LT77 would need more fettling.

christopher storey wrote: ↑

Sun May 23, 2021 5:01 pm

The LT77 was widely used so there are varieties of linkages available. Rover SD1 , Triumph TR7 5 speed, XJ6 S3 ( probably more common in 3.4 litre versions ) , LR, Sherpa!!-( but the ratios are not suitable on the Sherpa box ) . However, I think the OD box is more suitable because the LT77 was prone to a very sticky/baulky gearchange when cold which often could only be alleviated by using ATF instead of gear oil, and I have a feeling the OD dimensions are more suitable

I was amused to see this reference to the 77 gearbox (so called from the distance between its shafts). As a bright eyed student apprentice in the early 70s, my first task in the Triumph Technical Office was stress analysis on some of the springs in that unit.
If your gear lever doesn't centre well, my sincere apologies.

Have some experience of LT77 in Rovers- 2 SD1, 2 P6B converted, Discovery etc so...
The LandRover versions have longer input and output shafts so dont go there. In the SD1s I never got vigorous with the box, only trouble I had was clutch hydraulics. The later boxes known as R380 are repudetly stronger, have synchro reverse, taller 5th (.78 vs .83). Slightly longer in the rear cover area. the '380' is said to be its torque capacity in Nm. Usually only found in 2wd guise in TVR, maybe Morgan +8 etc.
The primary shaft has a plain nose and in Rovers it mates with a plain sintered bronze bush in the crank. From the front face of the box (where the bellhousing would attach) the primary is 195mm long, plain section 35mm, splines (23) 65mm long. The gearlever is 575mm from the front face, the drive flange 500mm from front face. The throwout lever (low on RHS) is clipped to a fulcrum bolt which comes in 3 lengths for different installations, coupled with 2 different lengths of throwout bearing carrier.
https://i.imgur.com/JjYlwKa.jpg
https://i.imgur.com/zKtiDBB.jpg
Rover Installations use the long throwout, middle fulcrum bolt. Get this wrong, you will either get a VERY heavy clutch, or no disengagement - BTDT. A clutch master of 0.625 or 0.7" will work well with a 0.875 slave cylinder. Rover clutch is a 9.5" unit.
The box serial prefix should tell you its original use , with a suffix as well - A and B suffixes are weakest, serial on the underside of the front of the iron case, later units had a flat pad near the drain plug on the side with serial on it. There are 2 different speedo drive gears on the output shaft, which mate with 6 different cable driving gears - look this up on gomog.
My current box in a P6B V8 is running well on Red Line MTL - original spec of 75W90 was changed early on due to poor changes when cold. Current spec is ATF Type F.
A search on LT77 in classicroverforum will bring up much info, as it is a common upgrade for the V8 P6B model.
I have seen pics of the gear change remote modified by cutting and shutting the alloy casting, some of the LandRover gearchanges for the box would bear investigation.
jp