For whatever reason, both my Scrambler and Cherokee came with weak 4 spds. Although, the T18a swap in the Cherokee wasn't necessary, the T18 swap in my Scrambler definitely was. The previous owner (or owner prior to him) swapped in a 304 in place of a 258. They neglected to upgrade the SR4 transmission and it was shot, a goner, fubar'd, when I got the jeep. I did some investigation into autos but decided on a T18 swap. I looked into the jeep CJ version with Dana 20s but decided I wanted to keep the Dana 300. This turned out to be a good thing because I ended up using my 4:1 geared 300 from my CJ7 and wouldn't have been able to do this if I used a Dana 20. So the opportunity came up locally to get a complete Ford T18 with Advance Adapters kit for Dana 300 that was installed in a CJ7. I liked the prospect of having all the work completed on the Ford T18 tail shaft, having the right bell housing included, the notched skid plate, the adapter and another tcase. Having all this would make for a very simple swap and I was able to get everything for around $800. 

One of the benefits I see in the T18 is the additional gear "range". For example, the Scrambler at the time had stock axles with 2.73 ratios and the SR4 had a first gear ratio of 4.02, T18 is 6.32 "granny" gear. Although the T18 is not an over-drive transmission, it does provide more gear "range" than the CJ T5 5 spd. With 2.73s, the T18 has a 1st gear overall drive ratio of 17:1 (6.32 x 2.73) and a "high" gear ratio of 2.73. A T5 with 3.73s has a 1st gear ratio of 15 (3.73 x 4.02) and an overdrive ratio of 3.21 (.86 / 3.73) . As you can see the T18 with taller gears is both "lower" and "higher" than the jeep T5. This gearing is for 33" tires by the way but basically sums up my philosophy on axle and transmission gearing options. Obviously, the T5 is really not strong enough behind a 304 but this is why I have swapped in 2 granny trannys in my jeeps. 

Anyway, here are some pics of the installation:

Here is the resurfaced flywheel and the Advance Adapters pilot bushing in place

Here, the bell housing, clutch and throw-out bearing are in place. This also shows the different T18 bell housing bolt patterns (T176/150 and Jeep T18).

And here is a shot of the Advance Adapter.

Another thing that works out well with this swap is the Ford T18 and this adapter make the trans length between the bell housing and tcase the same as the SR4, T4 and T5. This means there is no need for different length front and rear driveshafts. Also, as you can see in the above pic, the tranny mount is on the adapter and this lines up with the position of the original mount requiring no changes to the cross-member.

That's all I have for now. I have only had a chance to drive the scrambler briefly due to the accident but view the time in effort of the swap well worth it.