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[IrishCJ6]

Can anyone tell me what ratio the T18 box in a J20 would be, I have the potential to get one and the D20 but wanted opinions. It's mated to a 258.

[Jonny Jeep]

The gear ratio calc on grimmjeeper.com gives figures for T18(close ratio) and T18a(wide ratio). Looks like only first and reverse differ. I've no idea myself which you'd be looking at but here's the figures.

T18

1st Gear    4.02
2nd Gear    3.09
3rd Gear    1.69
4th Gear    1.00
Reverse    7.82

T18a
    
1st Gear    6.32
2nd Gear    3.09
3rd Gear    1.69
4th Gear    1.00
Reverse    7.44

[wildwood]

Lighthouse told me that all the T18s they have seen in the UK had the more desirable low ratio....
The higher ratio being an option on CJs ....allegably.....

[j33pky]

They are.  Mine had a 18a in the 79 j20

[wildwood]

Also Lighties have a bucket full of the T18a boxes from scrapped rusty hulks..... I was on the hunt about .3 years ago.....

You just have to go the shortening and rebuild route to get it to fit a CJ...... I used to have a link but no longer..... Bet it's on Pirate tho

[j33pky]

Ask king Cj! He bought mine for a Cj I believe

[IrishCJ6]

My understanding is I have to change the transfer mount and shorten the rear drive shaft and lengthen the front, the rest should bolt up no problem

[wildwood]

http://www.jeepfan.com/projects/cj-t-18a-transmission-swap/

there you go......hidden on an old computer 'bookmarks......' hope it helps

[king cj]

The j20 one will bolt straight in if you get the bell housing with it.you will have to move your gearbox/transfercase mount. Your props might have to be lengthened/shortened.make sure the gearbox came from a j20 straightsix, most of the j20 one in this country did but there may be a few v8 ones which might have a massive input shaft like the waggoneer ones