Pending SIII gearbox swap for my IIa

[WilsBoar]

You all have been pretty patient with my questions about this swap for which I am grateful. But now the time has come for action. I am heading over to the SIII donor vehicle to pull the parts I need this Saturday.

For clarity:

I plan on pulling the bellhousing and the gearbox from the SIII. I understand that my transfer case should mate up with the SIII gearbox. Do I need to pull the SIII transfer case as well to make this all work?

Mine and the donor are both 4 cylinder engines. I understand that the SIII clutch mechanism does not function in the same manner as the SIIa so there might need to be some reconfiguration. But I am still not clear if I even need the SIII bellhousing or if I can literally just replace the SIII gearbox with mine and keep everything else the same. (bellhousing & transfer case).

Thanks for the final clarification!

[JSBriggs]

You will need the bellhousing to correspond with the type of clutch throwout you plan on using.

IE: If you use the S2 oil bath throwout, you need the S2 bellhousing. If you use the cartridge S3 throwout, you need the S3 bellhousing.

-Jeff

[SafeAirOne]

I'd recommend taking the bellhousing, transmission and transfer case as a single unit. The only thing I'd leave is the starter (unless you need one).

That way, it's a simple job--take out the old assembly, install new SIII clutch kit (new bearing, disk and pressure plate), slap in the new assembly, hook up and bleed the new clutch slave, connect handbrake actuator and 2 shafts and you're done in 3-4 hours if you work efficiently and have no unexpected issues.

[daveb]

Don't forget trimming the gusset on the bellhousing crossmember of the IIa chassis in order to make room for the SIII slave cylinder.

Wilsboar, you should know that on a series LR, changing the bellhousing is a little more complicated than it is on some american and other vehicles where the gearbox is an entirely self contained unit. On a series LR the bellhousing is also the front wall of the gearbox casing and retains the input shaft (primary pinion) when it is removed. You will need to take the throwout bearing mechanism/housing off, undo the retaining nut on the layshaft, and then undo and remove the four big bolts that retain the bellhousing. The layshaft constant speed gear will hang up on the bottom lip of the gearbox housing so you need to wiggle things a bit to get the bellhousing free. In the process you will likely pull the layshaft out of its rear bearing, so make sure it is properly seated before putting the new bellhousing on. When you put the IIa bell on the SIII box, make sure you use the layshaft gear from the IIa box and not the one from the III. Use a good sealer like RightStuff™ to seal the bell to the rest of the housing. When you replace the bell, stand the gearbox on end and with your finger through the hole in the layshaft gear, hold it in mesh with the input shaft gear and place it down on the main box housing. I think the big nut for the layshaft requires red loctite though I'm not sure. You'll be using the layshaft nut from the SIII box BTW. There is also a thick cone shaped washer behind the nut that IIRC is also a spacer that is supposed to take up any end float between the gear and the shaft. You can compare the thickness of the IIa gear you are putting on and the SIII gear you are removing to see if you need to change the washer. Best check the manual for that info a my meory is a bit fuzzy on that part. You'll also want to know the torque specs where they exist and oh yeah don't forget to replace the little chintzy plastic bearing between the front of the mainshaft and the rear of the input shaft. If you don't already own one, now is the time to buy or download a factory service manual.

Or, just put in the SIII box complete like SafeAir suggests.


I'd recommend taking the bellhousing, transmission and transfer case as a single unit. The only thing I'd leave is the starter (unless you need one).

That way, it's a simple job--take out the old assembly, install new SIII clutch kit (new bearing, disk and pressure plate), slap in the new assembly, hook up and bleed the new clutch slave, connect handbrake actuator and 2 shafts and you're done in 3-4 hours if you work efficiently and have no unexpected issues.

[BackInA88]

I used the Series III gear box guts in my old Series IIa bell housing and case.
As iI was replaced all the bearing and seals at the time anyway.
Worked out sweet!

[WilsBoar]

Thanks DaveB! Excellent rundown.