Thread: Which Gearbox?

Obviously the V8 has been there a fair while, otherwise you'd have said something. Keep searching about gearbox numbers, as there is a fair amount of info on it. A little refresh of memory indicates that a SII box is not necessarily a problem. ( Which gear is not syncro? It may have been rebuilt to SIII specs.) The V8/series conversion generally twists propshafts.
If the gearbox works Ok, and the oil is good - leave in it a while and stay off the loud pedal. If you want to turn the SIII into a beast, then a LT95 is a good idea - but you may have to alter a crossmember etc. Your Fairey OD won't fit the LT95, but there are a number of OD's for it floating around. Also consider a R380.

I am not up on gearbox numbers, but from the clutch arrangement, it is a Series 3 box (although this is not definitive - the bell housing etc can be swapped with some caveats).

The Series 3 box is usually considered a little more fragile than the later S2a boxes, although late ones are probably not very different.

However, neither of these boxes is usually considered to be strong enough for the V8, and the Fairy overdrive definitely is not, although they will survive given sufficient care in driving.

The LT95 is certainly considered the strongest of the Rover gearboxes, but it is designed for full time four wheel drive, so to use it in a Series Landrover means modifications to the integral transfer case to allow part time four wheel drive or to the front axle and prop shaft to allow full time four wheel drive. It is also a lot bulkier than the Series gearbox, and will involve modification to both cross members and floor/transmission tunnel/seatbox. The Fairey overdrive does not fit the LT95, but there are overdrives made for it. Whether they are necessary is less certain, as there are a variety of different high range gear sets for the LT95.

John

Originally Posted by langy

Obviously the V8 has been there a fair while, otherwise you'd have said something. Keep searching about gearbox numbers, as there is a fair amount of info on it. A little refresh of memory indicates that a SII box is not necessarily a problem. ( Which gear is not syncro? It may have been rebuilt to SIII specs.) The V8/series conversion generally twists propshafts.

I brought this series III as an unfinished project, actually it was two series III's one complete and the other a restored chassis with all its dis-assembled parts in a pile next to it, except engine & gearbox. I'm hoping to make a good one out of the two.
The complete one is not running as one of the welsh plugs has corroded and coolant pours out of it, plus the starter will not work. I have just removed the starter and about to test its operation on the bench (any suggestions here, most welcome). I have no idea which gears are syncro'd or not, can this be tested without splitting from engine?
It does have a Salisbury diff though, about the only thing I know will be up for the job! Gearbox work is new to me other than replacing a clutch, so please excuse my lack of experience here.

Does the R380 bolt straight on? I have a Lake adaptor plate if that helps.

Originally Posted by JDNSW

I am not up on gearbox numbers, but from the clutch arrangement, it is a Series 3 box (although this is not definitive - the bell housing etc can be swapped with some caveats).

The Series 3 box is usually considered a little more fragile than the later S2a boxes, although late ones are probably not very different.

However, neither of these boxes is usually considered to be strong enough for the V8, and the Fairy overdrive definitely is not, although they will survive given sufficient care in driving.

The LT95 is certainly considered the strongest of the Rover gearboxes, but it is designed for full time four wheel drive, so to use it in a Series Landrover means modifications to the integral transfer case to allow part time four wheel drive or to the front axle and prop shaft to allow full time four wheel drive. It is also a lot bulkier than the Series gearbox, and will involve modification to both cross members and floor/transmission tunnel/seatbox. The Fairey overdrive does not fit the LT95, but there are overdrives made for it. Whether they are necessary is less certain, as there are a variety of different high range gear sets for the LT95.

John

I thought it was a series III gearbox to start with too, because of the clutch slave cylinder mounted horizontally on passenger side. But like you said the bell housing may have been swapped. I only started to think otherwise by the serial number suffix A which seems to suggest an early series II gearbox. I have only come to this conclusion from unconfirmed info off the net, hence, why I was hoping for help here from those with way much more experience than me
The problem with these type of rebuilds, is knowing exactly what parts you have to restore, however, you learn so much in the research trail.....
My last restoration, a mini moke, I didn't have the internet!!

Firstly a 9 prefix sequence number (8 digits) is SIII and SII gearbox numbers will have 9 digits and no suffix.
Secondly it has a SIII bellhousing, so while they can be fitted to SIIa boxes they can only be fitted to suffix B or later layshafts.
It is very easy to tell, drive it down the driveway and if it's synchromesh in 1st and 2nd its SIII.

The Suffix D series box is stronger than the rest of the S1 and SII gearbox because of the shouldered layshaft, larger layshaft bearings and larger intermediate shaft in the transfer box, but, of course, some (not all) of these modifications were in earlier suffixes.

The SIII layshaft cluster is stronger than the SII/SIIa splined layshaft, but the Suffix A SIII had a reputation of throwing the reverse idler through the case and all SIII boxes suffer from the very narrow size of the 1st and 2nd mainshaft gears.

The R380 has various models, assuming yours is a 4cyl, it is likely that you could get the short bellhousing R380 from a 200TDi Defender to fit in the space, but you either need to replace centre diff with the Santana or Ashcroft 2WD conversion or fit Stage 1 CVs to the front axle assembly.

If you used any later gearbox, it will be meant for full-time 4wd. You don't just put Stage I CVs in the front axle, but you have to change the whole front axle to one from a Stage I, which is an easy swap, but expensive if you need to rebuild it. (I know - I did it on my SIIA.) A 2WD drive conversion would be easier.

If I were you, I'd do the basics to get the car actually driveable, and then see what you want to do with it. It's too easy to rebuild a car on the theory of what you think it will be like, and then not like it when it's done. (I know - I did that on my SIIA, too!) And then you start converting things, it can get really complicated. (I know - I'm doing that at the moment with my SIIA.) The V8 was used quite happily with Series gearboxes in the olden days, but with a very light right foot!

Originally Posted by Davo

If you used any later gearbox, it will be meant for full-time 4wd. You don't just put Stage I CVs in the front axle, but you have to change the whole front axle to one from a Stage I, which is an easy swap, but expensive if you need to rebuild it. (I know - I did it on my SIIA.) A 2WD drive conversion would be easier. ...

que?

Yes to fit the Stage 1 CVs you have to fit the stage 1 chrome swivel balls and Stage 1 stub axles. .

But you don't have to fit the 3.54:1 diffs, you don't have to fit the Stage 1 3" wide 11" brakes (same as 6 cyl), you can use the same swivel housing as on any SIIa or SIII front end and you don't have to use the Stage 1 diff housing.

I know because I converted a SIIB to stage I CVs and swivels

All true, but since we're talking about a full-time 4wd gearbox that would lead to the use of a Stage I front axle, I would be inclined to use the axle housing that points the diff nose up at the gearbox, and to use the double-cardon joint on the front driveshaft as well. I think it's one area where the factory really put the effort into getting it right instead of just changing a few bits and putting up with the subsequent vibrations from the full-time drive.

Also, if you're replacing the stub axles to suit the CVs, then you're going to replace the hubs to suit the stub axles, since they are the later ones with both inner and outer wheelbearing the same. (And if you're going to do that, then you should get some oil catchers and put them in - I did, and they do the trick when a hub leaks.)

But with a V8 you'd probably want the 3:54 diff anyway. And an upgrade to the brakes to what the factory did with the last of the 88" SIIIs, though, if it's a SII we're starting with, then with the later hubs with the bigger wheel studs they'll need the SIII drums anyway.

P.S. No, there's no hope for you, Geezer! Not if you've already restored a Moke.