T18 first gear.

This has probably been asked and answered a thousand times over the years:
Could I upgrade a T18 with a 4.02:1 first gear to the 6.32:1 I want for crawling.
Getting basic machining done isn't a problem.
If it can be done whats the chances of finding the bits on eBay US for a reasonable price?
(hardly anything like that ever comes up in the UK, you could search for 10 years and find nothing)

 

No, none of the gears are compatible between the two transmissions. There was no input shaft made with the right length for the close ratio transmission that has the wide ratio (6.32:1 1st) gearing.

You may as well buy a complete 6.32:1 Ford T-18 transmission and convert your Jeep to that transmission.

 

Someone here who knows more about the T18 than I can answer your question about whether or not it can be done. I would assume it can be...because there was a t18 manufactured with the 632 1st.....Which brings me to the reason I posted. I am almost positive that I have nearly all the parts stashed away to build a complete T18 with the 632 1st. So if it will work, contact me and I will see what I have.

AAAh...tim posted first.

 

The input shaft for the close ratio (CR) T-18 is a unique length since it uses a plate adapter to connect the T-14/T-15 bell to the Jeep T-18 case. The only way you can do it is to swap out all the gears to the wide ratio (WR) set - and then the best you can do is to reuse the main shaft, case and adapter, and change everything else. You can't just change 1st, because it meshes with the cluster. You can't change the cluster without changing the input gear. You have to change all the gears.

The WR gears from a 70-76(79?) FSJ with a 258 and T-18 might work, since that transmission probably uses the same setup as the intermediate CJs, except WR gearing. Finding one of those for this use is impractical due to scarcity (plus I'm only theorizing that they are the same - might not be).

If you wanted to put together a 'kit' to do this, I think the lightest/fastest/cheapest way is to use a T-150/T-176 bell and Ford gears. Not a trivial project, since the new bell will change the OAL (overall length) and you'll need to move stuff around and change the driveshaft lengths.

 

Cheers Gents,

Err.... I seem to have opened quite a can of worms here haven't I!
The reason I posted was that the transmission in question is up on eBay UK for GBP100 start bid.
There's a dana20 T/C on it but the seller says it's 4.02 not 6.32 so I'm not sure where it has originated from, but he also says it has an AMC pattern bellhousing.
He has a pair of FSJ axles on too, but they are from a '78 and look to be quadratrac type.
I suspect the shipping costs of all the T18 W/R internals to the UK would probably make the project unviable, but thanks for the offer anyway.
Also the gearbox is about about 150 miles away from me, but that's probably almost neighbours in american terms.
While I'm thinking about it, isn't the T150/176 bell 2" shorter than the T14/15 type?

 

Maybe not as much as 2", but shorter. Definitely different depth.