SIIa/III Gearbox - Land Rovers Only

01001010 · 01-10-2008, 02:09 AM

I've only done minor research on this topic and for the sake of bringing some tech into the board, I'll go ahead and ask...

Can I stuff SIII gearbox internals into a SIIa housing?

I've been doing some lookin around and while I still havent made any phone calls yet, I cant seem to find price for a WHOLE gearbox assembly from British Pacific and Wise Owl.

So far, Atlantic British has the lowest price on a SIII gearbox w/o the TC but if there's the possibility of just switchin out Gears 1 & 2 to sync gears, that'd be great!

slouzon · 01-10-2008, 03:11 AM

Not as simple as changing out 2 gears.
The layshaft is different and I believe the main shaft and well as the reverse gear.
I switched my IIa over to full synchro but retained my IIa bell housing.
Not a bad job.
I bought a Series III box for my parts.
I took some pictures as I took stuff apart and of course while it was apart replaced all the bearings and bushings. My synchros were in good shape.

TerryS · 01-10-2008, 03:53 AM

The short answer is no.
The long answer is no, and why would you want to?
The 2A box is more robust, so learn to double clutch.

KevinNY · 01-10-2008, 06:14 AM

Of course if you put a Series III gearbox in front of a IIA transfer case you get the lowest series gear combinations. Your 1st lo goes from 40:1 to 50:1. While it is fashionable to say a IIA gearbox is stronger in theory, I have a run a III gearbox with 80K on it with 34" swampers, lockers, and a 9:1 ACR power plus motor. A friend runs the same box with portal axles and a 3.5 carbed V8. As long as you are not a ham fisted shifter you will be fine.

jimfoo · 01-10-2008, 06:45 AM

Never knew that about the III boxes. Good info to know. I see reverse is lower as well though it needs to be a suffix A or B transfer case or low range gears as C and later had a different ratio.

KevinNY · 01-10-2008, 07:54 AM

Series III has a lower 1st and reverse and IIa transfer cases have the 2.88 lo range vs. 2.35 for the III. Now if someone would just invent an under/overdrive transfer case.

slouzon · 01-10-2008, 08:22 AM

I've had them both apart on my bench and other than the synchros it's pretty much the same, except the one piece layshaft.
So if you wear out the synchros you now have a IIa box!

antichrist · 01-10-2008, 11:36 AM

Quote:

Originally Posted by KevinNY

Series III has a lower 1st and reverse and IIa transfer cases have the 2.88 lo range vs. 2.35 for the III. Now if someone would just invent an under/overdrive transfer case.

You mean like Ashcroft?

jimfoo · 01-10-2008, 01:38 PM

Only suffix A and B have 2.89:1. The C and onwards have 2.35 just like the III. I have a suffix C xfer and had to put B low range gears in it to lower my low range.

KevinNY · 01-10-2008, 01:46 PM

Quote:

Originally Posted by antichrist

You mean like Ashcroft?

Nope, the Ashcroft kit just raises Hi range but unfortunately comes with the 2.35:1 lo ratio.

jimfoo · 01-10-2008, 03:19 PM

And I hear you can't use the B gears with the Ashcroft. Another reason why an OD is better.

01001010 · 01-10-2008, 03:35 PM

Ok, so I'm going to give the double-clutchin a go. I know I'll get it eventually. Will keep everyone updated in the project Wilks thread.

But...

Say I get tired of double cluthin or w/e... Does a SIII gearbox bolt right up?

jimfoo · 01-10-2008, 04:00 PM

Clutch slave is on the opposite side but it will bolt up though you may have to cut off a reinforcement on the frame if yours has one as it will be in the way of the slave.

This is with my VW engine and adapter, but shows where it will hit on the drivers(USA) side.

01001010 · 01-10-2008, 04:12 PM

Hmmm...I wonder if the RHDers have that same support bracket. Anyway, I was just YouTubing Double Clutch videos and I'm just making a big fuss...I'll get it.

It's good to know that if I DID want to bolt one up, that it could.

Thanks Guys! This is only the beginning of a TON of questions. Your help is ALWAYS appreciated!

jimfoo · 01-10-2008, 04:28 PM

I usually start in 2nd anyway, so only have to double clutch to downshift.

01-10-2008, 02:09 AM	#1 (permalink)
01001010 Moderator Join Date: Jan 2005 Location: Lawrenceville, GA Posts: 4,526 Gallery: 15	SIIa/III Gearbox I've only done minor research on this topic and for the sake of bringing some tech into the board, I'll go ahead and ask... Can I stuff SIII gearbox internals into a SIIa housing? I've been doing some lookin around and while I still havent made any phone calls yet, I cant seem to find price for a WHOLE gearbox assembly from British Pacific and Wise Owl. So far, Atlantic British has the lowest price on a SIII gearbox w/o the TC but if there's the possibility of just switchin out Gears 1 & 2 to sync gears, that'd be great! __________________ JC... 1996 Discovery SE - The Blue Marlin - gone =( 1965 Series IIa 109 RHD 2.25L Dsl - Wilks 1965 Series IIa 88' LHD 2.25L Petrol - Fionna

01-10-2008, 03:11 AM	#2 (permalink)
slouzon Back in a Series LR after 25 years :-) Join Date: Dec 2006 Location: Troy, Michigan Posts: 114 Gallery: 0	Not as simple as changing out 2 gears. The layshaft is different and I believe the main shaft and well as the reverse gear. I switched my IIa over to full synchro but retained my IIa bell housing. Not a bad job. I bought a Series III box for my parts. I took some pictures as I took stuff apart and of course while it was apart replaced all the bearings and bushings. My synchros were in good shape. __________________ Back in a LR after 25 years!!! 71 Series IIa 88 01 D2 "BackInA88" on all the other LR forums (Sign up here first and couldn't think of a good handle at the time! )

01-10-2008, 06:14 AM	#4 (permalink)
KevinNY Senior Member Join Date: Sep 2006 Location: Guilderland, NY Posts: 767 Gallery: 0	Of course if you put a Series III gearbox in front of a IIA transfer case you get the lowest series gear combinations. Your 1st lo goes from 40:1 to 50:1. While it is fashionable to say a IIA gearbox is stronger in theory, I have a run a III gearbox with 80K on it with 34" swampers, lockers, and a 9:1 ACR power plus motor. A friend runs the same box with portal axles and a 3.5 carbed V8. As long as you are not a ham fisted shifter you will be fine. __________________ "The Goat",1973 Series III coil conversion, Daihatsu 2.8 Td, power steering, dual ARBs Etc.

01-10-2008, 06:45 AM	#5 (permalink)
jimfoo jimfoo Join Date: Mar 2007 Location: Colorado Posts: 414 Gallery: 9	Never knew that about the III boxes. Good info to know. I see reverse is lower as well though it needs to be a suffix A or B transfer case or low range gears as C and later had a different ratio. __________________ Jim Hall “That man has no respect for his Rover and beats the hell out of it every opportunity he gets, taking the most difficult line over each and every obstacle.” Michael 1966 88" 1.9l VW TDI, GT1749V, IC

01-10-2008, 07:54 AM	#6 (permalink)
KevinNY Senior Member Join Date: Sep 2006 Location: Guilderland, NY Posts: 767 Gallery: 0	Series III has a lower 1st and reverse and IIa transfer cases have the 2.88 lo range vs. 2.35 for the III. Now if someone would just invent an under/overdrive transfer case. __________________ "The Goat",1973 Series III coil conversion, Daihatsu 2.8 Td, power steering, dual ARBs Etc.

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01-10-2008, 03:53 AM	#3 (permalink)
TerryS Moderator Join Date: Aug 2004 Location: Bloomfield, CT If I died today, I lived there all my life. Posts: 2,151 Gallery: 0	The short answer is no. The long answer is no, and why would you want to? The 2A box is more robust, so learn to double clutch.

01-10-2008, 08:22 AM	#7 (permalink)
slouzon Back in a Series LR after 25 years :-) Join Date: Dec 2006 Location: Troy, Michigan Posts: 114 Gallery: 0	I've had them both apart on my bench and other than the synchros it's pretty much the same, except the one piece layshaft. So if you wear out the synchros you now have a IIa box! __________________ Back in a LR after 25 years!!! 71 Series IIa 88 01 D2 "BackInA88" on all the other LR forums (Sign up here first and couldn't think of a good handle at the time! )

01-10-2008, 01:38 PM	#9 (permalink)
jimfoo jimfoo Join Date: Mar 2007 Location: Colorado Posts: 414 Gallery: 9	Only suffix A and B have 2.89:1. The C and onwards have 2.35 just like the III. I have a suffix C xfer and had to put B low range gears in it to lower my low range. __________________ Jim Hall “That man has no respect for his Rover and beats the hell out of it every opportunity he gets, taking the most difficult line over each and every obstacle.” Michael 1966 88" 1.9l VW TDI, GT1749V, IC

01-10-2008, 03:19 PM	#11 (permalink)
jimfoo jimfoo Join Date: Mar 2007 Location: Colorado Posts: 414 Gallery: 9	And I hear you can't use the B gears with the Ashcroft. Another reason why an OD is better. __________________ Jim Hall “That man has no respect for his Rover and beats the hell out of it every opportunity he gets, taking the most difficult line over each and every obstacle.” Michael 1966 88" 1.9l VW TDI, GT1749V, IC

01-10-2008, 03:35 PM	#12 (permalink)
01001010 Moderator Join Date: Jan 2005 Location: Lawrenceville, GA Posts: 4,526 Gallery: 15	Ok, so I'm going to give the double-clutchin a go. I know I'll get it eventually. Will keep everyone updated in the project Wilks thread. But... Say I get tired of double cluthin or w/e... Does a SIII gearbox bolt right up? __________________ JC... 1996 Discovery SE - The Blue Marlin - gone =( 1965 Series IIa 109 RHD 2.25L Dsl - Wilks 1965 Series IIa 88' LHD 2.25L Petrol - Fionna

01-10-2008, 04:00 PM	#13 (permalink)
jimfoo jimfoo Join Date: Mar 2007 Location: Colorado Posts: 414 Gallery: 9	Clutch slave is on the opposite side but it will bolt up though you may have to cut off a reinforcement on the frame if yours has one as it will be in the way of the slave. This is with my VW engine and adapter, but shows where it will hit on the drivers(USA) side. __________________ Jim Hall “That man has no respect for his Rover and beats the hell out of it every opportunity he gets, taking the most difficult line over each and every obstacle.” Michael 1966 88" 1.9l VW TDI, GT1749V, IC

01-10-2008, 04:12 PM	#14 (permalink)
01001010 Moderator Join Date: Jan 2005 Location: Lawrenceville, GA Posts: 4,526 Gallery: 15	Hmmm...I wonder if the RHDers have that same support bracket. Anyway, I was just YouTubing Double Clutch videos and I'm just making a big fuss...I'll get it. It's good to know that if I DID want to bolt one up, that it could. Thanks Guys! This is only the beginning of a TON of questions. Your help is ALWAYS appreciated! __________________ JC... 1996 Discovery SE - The Blue Marlin - gone =( 1965 Series IIa 109 RHD 2.25L Dsl - Wilks 1965 Series IIa 88' LHD 2.25L Petrol - Fionna

01-10-2008, 04:28 PM	#15 (permalink)
jimfoo jimfoo Join Date: Mar 2007 Location: Colorado Posts: 414 Gallery: 9	I usually start in 2nd anyway, so only have to double clutch to downshift. __________________ Jim Hall “That man has no respect for his Rover and beats the hell out of it every opportunity he gets, taking the most difficult line over each and every obstacle.” Michael 1966 88" 1.9l VW TDI, GT1749V, IC

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