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MG MGB GT V8 Factory Originals Technical - LT77 gear extension

Is it possible to replace the gear extension mounting rubbers on an LT77 gearbox fitted to a factory V8 without removing the gearbox? There doesn't seem to be a lot of room through the top tunnel opening. Has anyone done this?

Ian Thomson
ian thomson

Yes done it, take the cover plate off the tunnel. You will be able to get at them if you undo the g/box cross member and lower it a bit on a trolley jack.
Allan Reeling

Likewise - but from underneath - using poly bushes now.
R Walker

Thanks for the replies. I take it poly bushes are the way to go. Are the ones Clive Wheatley has Poly or as original.

Ian Thomson
ian thomson

Ian - Clive is a shrewd operator and always looking for genuine improvements - ask him what he has. Otherwise Rimmers of Lincoln - have both. Yes, it is the way to go.
R Walker

May I join in, although I don´t own or drive a V8?
In fact, my car is a 1964 MGB with a 2-lire-engine and a Rover SD1-box (LT77) instead of the original 4-speeder.

I built this conversion myself in 1983 and it usually works very well. But now I need to replace my LT77. It´s very noisy when accelerating in 1st, 2nd and 3rd gears.

Does anybody have more infos about this gearbox? I am looking for a sort of manual and info about the numbers on the box – they give a clue as to what ratios are inside, so I was told.

I also need a parts supplier: all the rubber mounts on the gearshift extension have deteriorated and need replacement. Rimmer doesnt seem to have LT77-parts anymore.

The pic shows the LT77 in situ before the drivetrain is installed



Here's a little piece from RPI
And another bit from Paddock
Here's an article with links to pdf files on the LT77
I have a R380 box from TM Transmissions. He has a FAQ page for the LT77.
TM can do you an exchange LT77 from £375. He must get spares from somewhere - email him and ask.

Several years ago I rebuilt a LT77 using a kit from here
It wasn't very successful, and although the gearbox worked OK it made a horrible noise. I eventually traded it in with TM Transmissions for the reconditioned R380.

Hope this is of some help.
Mike Howlett

Somewhere on the internet is a complete service manual for the LT77. I printed it out and used it. Not sure how to locate it now, but if I find out I'll post here.
Mike Howlett

Here's a photographic record
Mike Howlett

thanks for your help and for the links!


This thread was discussed between 27/01/2012 and 19/02/2012

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