LT77 alignment (and history)

Tor

Tor

Well-Known Member
Hi all,

I can't seem to find photos of an LT77 rear mounting fitted to a P6B auto tunnel, preferably using the welded-in bracketry. Can anyone help with that and/or measurements? There's an original SD1 crossmember/bracket to work from.

At the same time we're trying to sort out the drive flange positioning, which was not checked prior to pulling out the old unit and engine :oops: Stan "Vaultsman"'s thread from his own conversion noted 155mm from the top of the tunnel in his 'S'. Any reason why that'd be any different in an auto tunnel?

Finally, the box has a serial prefix of 25A that I can't find any data on beyond an SD1 forum member suggesting it might be ex-Land or Range Rover. The full number is stamped on as -25A042115C.

Thanks in advance for any pointers!

Tor
 
Hi Nick

The LT77 box was first used on the SD1 Rover, then migrated into the Sherpa van and finally got a transfer box and made it into the Discovery, Defender and Range Rover. It has a redesigned successor called the R350 that has a similar range of uses plus the MGRV8 and is interchangeable. It's the standard gearbox to use in a p6 in the UK. In NZ Toyota boxes are more readily available. If you are thinking of ditching your auto in favour of a manual, it's a pretty simple conversion. Biggest problem would be sourcing the pedal box!

Chris
 
Nicked this from the V8 Forum :oops:

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

If it has the 2WD rear end I doubt if it is a 4WD box.

You need to line it up so the gearstick sits centre in the tunnel, otherwise you will have difficulty getting reverse or 5th.

Have you got a pc of the gearbox?

Richard
 
hi tor,
it must be 8 + years since i have done this conversion. having the lt77 bracketry is excellent. i forget 100% but i remember that the bracket needs to be cut ( a 'V' shape if i remember ) then rewelded it then mounts to the existing brackets in the transmission tunnel.

ian
 
Thanks guys. Richard I found that list of applications/numbers too but nowhere is 25A mentioned. It's not essential though, as long as everything else seems normal. Being a C suffix box I understand it's got the 0.83 ratio 5th (not the most desireable 0.79 one). I'll try to get a photo up. We've rebushed the remote selector arm like Stan (vaultsman) did with his, and the box seems to have been overhauled shortly before Alan got it. What I wanted was to make sure the drive flange lines up like with the old auto box so it can go in, before I head back to Old Frosty tomorrow. Fortunately Alan here has a 2nd car he can take measurements from later on.
 
I have found a pic of the rear mounting bracket as fitted to my car

101_1586a.jpg


The right hand side was rammed up against the side of the tunnel, so I have chopped 1/4" off of it, which has allowed the gearstick to come up more centrally in the tunnel.

I didn't do this job though, so am not sure how good it is.

It is certainly solid enough but how well it is lined up is a mystery to me.

I would appreciate it if you could measure the distances from the output flange to the sides of tunnel, and the top. Car runs fine but it would be nice to check it :)

Richard
 
Richard that's great, thanks! So far the box has only been offered up on a trolley jack and it'll be a while before it is actually fitted. For now it's all about modifying that mount, and the engine needs doing as well. I reckon Alan's going to take measurements off his daily driver after which time I could post any good results. Knowing him he'll probably slot the bolt holes for adjustment purposes to get it all just right...
 
Alan had a look at that photo and says he now knows what to do Cheers again.

I've sent off a request to Rimmer Bros for a replacement mechanical-speedo drive pinion. There's one supplied with the box but in SA the SD1s ran 3.27 differentials, not 3.08 ones. I believe that would make the P6 speedo under-read even more than with the right one.

According to credible sources ... the 3.27 diff was to compensate for the lack of power in the cars, most of which ran on the Reef - ie. at elevations of 1400 to 1800 (Jo'burg) metres and so BHP figures in real life ran at 20% below.

I even found out today that my dad's car had a vinyl roof originally - a three-piece one.
 
So the roof must have been local. I wonder if the 25A gearbox is a local variation too? Since SD1's got the Australian 2.6 E6 is it possible they made their own gearboxes?

Chris
 
I think that 25A could be out of the SD1 2600 that we had in SA.
Revolting thing, couldn't pull the skin off a rice pudding and guzzled fuel like it was paid to.
 
chrisyork said:
So the roof must have been local.
Click to expand...
It was indeed. According to legend these could often have one of the seams dead straight with the other one going like a scenic railway. Like most SA fitted roof panels it had terminal rot at the rear and was eventually replaced with a non-vinyl one.
unstable load said:
I think that 25A could be out of the SD1 2600 that we had in SA.
Click to expand...
Ah. OK, that I guess is interesting. Although if memory serves it's essentially the same box as the V8?
 
Although if memory serves it's essentially the same box as the V8?
Click to expand...
It depends who you talk to. I have heard that they are the same and also they are different.

The main problem was the absolutely terrible control or rather, lack thereof, at Leyland SA at the time, meaning the closest box could have been good enough as opposed to the correct box...
I have heard horror stories coming out of there with cars rusting as they left the factory due to being barely painted, Jags being lead filled to line up panels and fill in production line damage, the list is long and sad......
The P6 V8's were locally assembled from CKD kits with local content and the roofs all rusted off at the pillars, while the 4 cylinder cars were assembled from PKD kits and hardly any of their roofs rusted. My V8's roof was held on by the tinworms when I bought it and I managed to find an ex-4 pot's pillars and roof frame at a breakers to fit to it.

I have 2 of those boxes, one supposedly out of a V8 and one not. I haven't bothered checking the numbers on them, but
now that you have got me thinking, I may do that. The supposedly ex-V8 one lasted about 6 months in my car after I fitted a slightly warmer cam before expiring in a Christmas tree of filings on the plug and some very sick noises.
 
Although if memory serves it's essentially the same box as the V8?
Click to expand...
It depends who you talk to. I have heard that they are the same and also they are different.

The main problem was the absolutely terrible control or rather, lack thereof, at Leyland SA at the time, meaning the closest box could have been good enough as opposed to the correct box...
I have heard horror stories coming out of there with cars rusting as they left the factory due to being barely painted, Jags being lead filled to line up panels and fill in production line damage, the list is long and sad......
The P6 V8's were locally assembled from CKD kits with local content and the roofs all rusted off at the pillars, while the 4 cylinder cars were assembled from PKD kits and hardly any of their roofs rusted. My V8's roof was held on by the tinworms when I bought it and I managed to find an ex-4 pot's pillars and roof frame at a breakers to fit to it.

I have 2 of those boxes, one supposedly out of a V8 and one not. I haven't bothered checking the numbers on them, but
now that you have got me thinking, I may do that. The supposedly ex-V8 one lasted about 6 months in my car after I fitted a slightly warmer cam before expiring in a Christmas tree of filings on the plug and some very sick noises.
 
Ouch John. I'll get Alan to consult his network, maybe they can shed some light on that. Especially since I have convinced him to go a little warmer too, with a 3.9 cam (great prices at Roverland!). Eish. But again, this box is supposed to be a recent rebuild, and Alan's not one to drive with heavy wellies on.
 
In all honesty, it was an unknown entity when I bought it and it fell foul of the input bearing failure, so if yours is rebuilt then you will be fine.
I have another one waiting in the wings that WILL be rebuilt this time if I decide to fit it, and a Toyota Cressida box that I swapped for a Weber 45 that is tempting me too......
 
I've just been corrected - Alan rebuilt the box himself, all bearings were off-the-shelf items except some form of needle rollers that he hadn't a number for. So that should be safe... I might try to get my dad on to the idea of a 5-speed next...
 
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