IIA gearbox into a III

[zed]

I've looked around... finding it hard to find info on going III to IIA transmission..

My SIII transmission needs repair. I found a guy that has a IIA with III internals with zero miles on it since the rebuild, cheap!

It has the IIa bell housing.

I was wondering if my SIII bell housing would bolt up to the IIA like nothing happened. Then bolt the transmission to my transfer case and be done. Rebuild the SIII box at my leisure.

If the bell housing isn't compatible. Is putting a IIA gearbox in a series III all that tough? Something about a slave bracket was brought up. I realize I'd have to plumb lines to the new clutch slave position and get a new pressure plate. But does it go beyond that? The seller says he has the linkage and if not.. its available for sale. As for this slave bracket, I can find no mention of it in catalogues or diagrams. But 2 different people have told me I need it.

And either way, it WILL mate up properly with my transfer case will it not?

Again, I feel like a burden asking all these questions...
I don't have much to offer in the lines of experience to a group like this.
If you ever need a document translated from chinese... don't hesitate to ask.

Cheers
Thanks for your time.

[slouzon]

I believe since the gear box already has Series III internals you should be able to put your Sries III bell housing and input shaft straight on with no problem.

Just remove the bolt from the layshaft and the bell housing bolts and pull it off.

When I switch my Series IIa internals to Series III I kept my Series IIa bell housing and input shaft. I can't imagine a problem going the other way since the trans already has Series III gears.


Steve

[zed]

THanks a lot. I'm not sure how the input shaft comes out (even after reading some of the manual) but i'm sure it will become clear when in front of me. ((edit: oh.. i get it the input shaft is not part of the main shaft, its more integral to the bell housing and drives the main shaft so if the shafts mate up.. then it'll be cool))

Yea.. i'll have to clarify what "series III internals" means. But thats what he said.
I suppose, since I plan on buying it anyway. I'll let you all know.


If there is a definite problem, I'd like to know about it though.

[slouzon]

The input shaft is attached to the bell housing and it will all come out as one piece.

[Nilhan WeeraSinha]

Hi,

I have just fitted a S11 gear box to my S111 as S111 boxes are hard to find in Sri Lanka.

I had to use my S111 bell housing as the S11 bell has a smaller diameter.

Had to grind down the large nut that keeps the shaft in place to get the S!!! slave assembly fitted.

Also added a guard similar to the one on the S11 to keep the main shaft razor in place. The S11 box is definitely stronger built! the S111 has only a 'C' clip to keep the main shaft in place

Cheers
Nilhan

[slouzon]

Originally Posted by Nilhan WeeraSinha

Hi,
I had to use my S111 bell housing as the S11 bell has a smaller diameter.

This is a new one to me?
Are you sure it didn't have a Series I bell housing?

[zed]

Still getting conflicting info from various sources..
I'm going to have to get it and see it seems.
Hope it works out.

[zed]

so.. the story is. Its totally SIII inside and input shaft. It has a IIA housing on it with a "custom found" bearing to make it fit the III shaft because it was for an ISUZU swap and the SIII clutch got in the way.
SO.. it should be all set to bolt up the housing etc from mine.

Picking it up/inspecting it, tomorrow.
I'm hopeful but cautious..

[Nilhan WeeraSinha]

Hi Slouzon,


I got two S11 boxes from a chap who now runs his S11A with Mitsubishi Jeep components ( Engine,gbox & dif)

The two boxes looked similar, the second box was a spare one he had purchesed but not used and was in good condition so I decided to fit this box to my S111. The sizes of the gear wheels did not look very different from those of my S111. I did not dismantle the Gbox as it looked OK, the only noticible difference was the bell which had the slave on the other side and the diameter was about half an inch too small to fit onto the S111 flywheel housing.
This Gbox may well have come off a S1 !!!!

I have no idea how to identify this? any clues ?

Cheers

Nilhan

[zed]

maybe something adapted to a different engine.. 2.6 or something even more exotic out of africa or something. Who knows (someone on this board for sure) From what I see, they all use the same flywheel (at least the same diameter) and there's not enough room for a variance the size you mention in my flywheel housing. About ... oh .. just a few mm from teeth to housing.

I was under the impression from reading that the II IIA IIA-H and III were near identical in and out. I've read a lot about people swapping them back and forth... no mention of new flywheel housing. Just clutch parts and double clutching. (Which brings up.. I hope this tranny is from '66+)

But you never know what people assume you already know I may be in for a big surprise.

Getting excited. Its a mystery!

Found this here Seems promising
Gearboxes:
" All gearboxes are interchangeable, though there are two types of bell housing stud patterns. The early pattern was used on the 1.6l and 2.0l engines. Swap the bell housings to fit the engine and gearboxes together. The later bell housing started in 1958 with the diesel engine, and is still used on current turbo diesel Ninety Defenders and Discoverys.

There are two types of clutch mechanisms used. The earlier was used for the Series I through Series IIA, while the later started with the Series III. The former is a more complicated system with external linkages, while the later uses a simple arm within the bell housing."

[p76rangie]

This may answer your queries. But be careful as there were other boxes, depending on what part of the world you are in. For example, there were military versions here in Oz that were very strong.

" The gearbox used in series Land Rovers was first used by Rover in 1932. This gearbox has undergone several modifications since then but is still basically the original design. This gearbox was considered advanced and strong when it was introduced and was finally discontinued because it could no longer be modified to hold up to the power and weight of newer Land Rovers.
From 1948 (first LR production) to 1950 the gearbox had permanent 4WD with a freewheel device in the front prop shaft. From 1951 Rover fitted a transfer case with the now well known 'yellow and red knobs' right up through series III.
The dipstick and top oil fill disappeared with the introduction of the "B" suffix gearbox. At that time the transfer case intermediate gear shaft diameter was increased for additional strength. In the autumn of 1963 the gearbox ratios and transfer case low gear ratio was changed with the introduction of the "C" suffix (See my gear ratio web page for actual ratio numbers of the different series and Coiler gearbox & transfer cases).
In the Autumn of 1966 Rover introduced the '1 ton' 109" with the 6 cylinder petrol engine (A small number of 4 cyl models were made in 1970/71) . The 1 ton version had a lower ratio gearbox and transfer case to accommodate carrying a heavier load, and to compensate for the 9.00x16 tyres that came stock under the 1 ton model. One ton models also had ENV axles instead of the standard rover type. The 109 forward control Land Rovers used the same gearbox and transfer case.
The factory built a small number of all syncro series IIA gearboxes just prior to converting the box into the series III gearbox. The all syncro series IIA gearboxes can be identified by a "S" prefix on the stamped number located on the transmission top cover. Since top covers can move about when multiple gearboxes are rebuilt, and a IIA gearbox is most likely to be rebuilt in the earlier documented style, the 'S' stamp on the top cover does not guarantee the gear box under the top cover is still all syncro.
The Series III gearbox has syncro in all gears as well as lower first and reverse gear ratios. The transfer case remained the same as was used on the late IIA. Series IIA gearboxes (D suffix & later) are generally considered to be stronger and longer lasting than early series III gearboxes (The ones imported into North America). Though a lot of this conception may have to do with people's shifting habits.
There was a final change made to the gearbox about half way through the series III production (After Rover left North America). These late series III gearboxes are considered by some to be the strongest of the Series Land Rover gear boxes.
In general the Series gearbox is considered to be strong enough for about 120 HP, 160lbft is about the limit on torque. Early gearboxes are considered to be weaker than later IIA gearboxes. Early gearboxes tend to beak layshafts and mainshafts at the circlip groove positions. Late 2A layshafts without the circlip groove are stronger than the early ones. According to Bob Shannon "Here is the fix for the earlier gearboxes. The layshaft from suffix D onwards gearboxes (part # 556040) has a stepped shoulder that fits into the rear of the D-onwards series layshaft 2nd gear. So you don't have to buy a matching set of gears (D-onwards is part # 600916) you can take an earlier layshaft gear from the pair (Suffix A-C is part # 245766) and machine out the relieved section to replicate the later gear's greater clearance. Also a suffix D layshaft is probably cheaper than the suffixes A (part # 09917) and B-C (part #528703). Make sure the mainshaft is set up correctly!!! "
The all syncro transmission has a reputation of being less robust than the earlier versions mostly because they do not hold up to quick shifting. The syncros must come to a stop when the shifter goes through the neutral position if the syncros are to last. When shifting an all syncro gearbox it is advised to hesitate just slightly in the centre of the 'H' pattern.”

The gearbox specification was changed in 1961 with the introduction of the Series IIA. The main gearbox had a beefed up lay shaft and a front bearing as well as a repositioned reverse gear idler (these used to break sometimes). The idler pin on the gearbox was also enlarged. This gearbox could even cope with the 6 cylinder engine without problem.
In 1971 an all new gearbox was introduced with the Series III. Basic differences were that this had a larger diaphragm clutch (Note: this larger clutch plate and diaphragm will fit on the older Series IIA bell housing) and the 4 speed synchromesh. This gearbox needs to be treated sensibly. The massive baulk ring assembly does not like to be rushed and can cause problems if it is. This gearbox is not considered to be as strong as the Series IIA gearbox as people tend to be rough on them be trying to power shift. "

[zed]

Yea.. thats what the full text of what I posted earlier.

OK..
Now I have the gearbox. Got it for 260 bucks (he wanted 350)..
Great tool to bring along with you when buying car stuff...a see snake . Took off the drain plug and looked around. Did the same with the frame when I bought the truck.

THe guy I bought it off has a Great condition Forward control.. featured in a boeing commercial and 2 episodes of ER. As well as a great 109 safari top (also featured in ER.. still has some dr's without borders decal on it). Also has an 88 "IIA" that actually has a bobbed range rover chassis under it. As well a couple range rover classics.
ANYWAY
A tiny bit of rust in the tranny. Nothing worth worrying about. It was all oily inside. Just some spots of rust.

It wouldnt shift at first but a little tap and the shifters freed right up.

Now I'm trying to get the bell housing off.
From what I understand, I have to take off the layshaft bolt.

SO... Is there any way to do that with without a transmission brake attached? Seems troublesome.

More research shows it to be the same exact transmission when viewed from the outside. Reverse switch and bell housing are the main differences. SO I should be good if I get these housings swapped.

The series IIA clutch is kind of neat oil bath bearing, heavy duty front end thing. Extravagant slave cylinder mechanism nearly cancels out the neatness of the internals though. Took me a bit to realize I had to drive out those pins to get the clutch rod out.

[antichrist]

Well, you need to stop the internals from rotating when you loosen the fixing. If you don't have the parking brake attached, which I assume is the case since you're asking, You can either attach it or use something on one of the output flanges. Attaching one of the propshafts and sliding a small bar through the u-joint to press against the floor (or have someone hold it) should work.
I've also done it, but only on gearboxes I'm completely rebuilding, by removing the top cover and wedging a piece of hardwood between the gears. Probably not something you want to do in the case as you can get bits of wood in the case.

[slouzon]

When the shift rod cover is off you can shift 1 of rods in a forward gear and than engage reverse as well and nothing will turn.

Steve

[p76rangie]

Originally Posted by slouzon

When the shift rod cover is off you can shift 1 of rods in a forward gear and than engage reverse as well and nothing will turn.

Steve

X2. That is how the manual states to do it.