LT77 Gearbox Help

[HeWhoDaresRoy]

I need to get a new LT77 gearbox for my early Chimaera and struggling to work out which is the correct one - a rebuild of the current one isn't an option.

So far I've seen that it needs to be a 'G' or 'H' suffix gearbox, but I'm just wondering if there were different TVR-specific ratios within these, or are they all the same?

Also, does anyone know if the shifter mechanisms are all the same?

Any input would be gratefully received!

[Hashtaggggg]

Have you spoken to Ashcroft transmissions?

[HeWhoDaresRoy]

Yep; they don't do 2wd LT77 rebuild/supply any more, from what I understood.

[MikeE]

It’s the Rover SD1 box/ratios

You’ll need to take the remote mechanism off and retain this as it’s TVR specific. You can rebuilt this mechanism replacing the 4 bronze bushes, two ball joints and the nylon cup at the bottom of the gearstick

Regarding Ashcroft, I spoke to them about rebuilding my LT77 and they informed me they do t do 2WD boxes anymore, I’m getting Hardy’s engineering to rebuild mine

[HeWhoDaresRoy]

That's great, thanks.

I had mine rebuilt, but it's still not right. It's been in and out of the car to be checked/rebuilt a couple of times over the last year and still no better (5th gear issue). I'm assuming the remote shifter linkage is all ok, so will ask for that to be put aside when the gearbox is removed.

[rev-erend]

I have used competition transmissions for my LT77.

https://www.gearboxman.co.uk/

[Belle427]

rev-erend said:

I have used competition transmissions for my LT77.

https://www.gearboxman.co.uk/

Sent one here recently myself, turned around quite quickly and reasonably priced.

[HeWhoDaresRoy]

Nice one, thanks everyone.

[wuckfitracing]

If yours is a 430 a lot of them were fitted with the Early Vitesse LT77s mine has a “B” suffix

[900T-R]

wuckfitracing said:

If yours is a 430 a lot of them were fitted with the Early Vitesse LT77s mine has a “B” suffix

Same here.

[Classic Chim]

What relevance does having a Vitesse box have?

[wuckfitracing]

Well he has said it needs to be a G or H suffix. But 430s weren`t fitted with G or Hs from new, so if he comes across an A B or C this would also replace his existing gearbox. Thought it might widen the search.

[Classic Chim]

wuckfitracing said:

Well he has said it needs to be a G or H suffix. But 430s weren`t fitted with G or Hs from new, so if he comes across an A B or C this would also replace his existing gearbox. Thought it might widen the search.

Excellent, I get it now

[Jon100p]

I found this on the V8 owners forum, which appears to be identifying 2wd models from the prefix rather than a suffix. Anyone know if this is correct?

“LT77 Gearbox Identification
Post by Coops » Fri Sep 28, 2007 3:36 pm
Gear box identification the identification marks can be found on an oval lug near the base of the box

G16A SD1 2000 (Could be 4 speed)
G17A SD1 2300/2600 5 speed
G19A SD1 3500 SE/VP 5 speed
G22A SD1 3500 Police spec 5 speed
G23A SD1 2600 Police spec 5 speed
G26A SD1 2400 Diesel 5 speed
G27A SD1 2000 Later model 5 speed
G28A SD1 Vitesse 5 speed
G30A Sherpa Range”

[Hoover.]

I looked at loads of options years ago and went for a T5 box replacement as a) I could not get a straight answer B) the original bid was like stirring porridge ...The T5 box is a great ...BUT the additional cost to change ...only if you do it yourself is my opInion ...I had a garage do it and please don’t ask the cost

[HeWhoDaresRoy]

Thanks again.

I got the 'G' or 'H' bit from someone who rebuilds the gearboxes, but isn't a TVR specialist, so assumed it was correct, but maybe not.

With hindsight, I should have gone the T5 route - the current gearbox has been in and out three times to no avail, but now just looking for a drop in replacement to keep it simple. I've had enough of the whole saga!

[MikeE]

My 4.5BV Griffith has an LT77 with a D suffix (28A 0155749D)

Regarding the comment about the gear change being sloppy, that could well be the remote mechanism that has a nylon cup, two ball joins and 4 bronze bushes in it, all of which wear but replacement parts can be sourced from RG Parts inexpensively

[HeWhoDaresRoy]

Thanks to the replies and pictures I now know the gearbox has to be from a Rover SD1 Vitesse (code starts with a '28') to get get the correct ratios and these gearboxes only went up to a suffix 'D'.

The later suffix gearboxes (E-H) would have the wrong ratios and were maybe only used in MOD applications.

Starting to make sense.

Edited by HeWhoDaresRoy on Friday 19th February 11:04

[FoxTVR430]

If this helps
This is my LT77 from a 430 Chimaera from late 93' during the rebuild.
No = 28A 02211 46B

[HeWhoDaresRoy]

Perfect, thanks!