It started when I bought my Cherokee off ebay in January 02. The owner told me it had a T18 and because I got it from Florida, I had the jeep shipped up here just to find out it was a T176. No problem, the 4 spd works fine and runs well with most driving situations. The jeep had been a daily driver for several months and the tall first gear (3.52) was starting to get on my nerves. The jeep has 33's and stock 3.31 ratio so first gear is tall so you have to ride the clutch sometimes in 1st gear but highway speeds/rpms are right on.

Investigation

So I make the decision to do the T18 swap in my daily driver after hrs of riding my the clutch in bumper to bumper traffic. I weigh all the options and decide I want the T18a and NP208 combo from an 80+ J20. The T176 is mated to a NP208 with drivers side front axle drop on my chero. I did some research on aftermarket adapters for the T18 and NP208 but nobody makes an adapter for the long shaft T18 in full size jeeps. The rare 4 wheel drive Ford T18 and NP208 (or 205) appears the same as the J20 version but does not have the bell housing spacer. I also used the Offroad.com T18 page as a reference but there are some inconsistencies like the spline count being 31 instead of 23 on the J20 T18/208. Anyway, my jeep has brand new exhaust installed by the previous owner that would have to be re-routed if I used the T18a Dana 20 combo and I would have to swap front axles for pass side drop. A T18/20 was available here locally so searched for a WT, 3.31, pass side drop front axle but couldn't find one. I didn't want to deal with regearing another front to match my gears so opted for the elusive T18/208 instead. Also to my mind the T18a and NP208 is one of the lowest factory offered tranny/tcase combos out there with 6.32 first and 2.62 low! With my 3.31 gears, I will have a respectable 55:1 low.

I had a local junkyard broker do a search for me and after a couple weeks he found them in Ohio but they wanted 825! Ouch! I thought, oh well, pay the piper. The price included shipped and my broker brought the parts to me right at work, which was great. I was able to sell my old T176 and NP208 for half of the T18 price so that helped.

Here is the trans in the crate is was shipped in, notice the round bolt pattern and 31 spline output for the t-case

Here is the tranny showing the long input and output shafts.

I found this pic on the web showing what the T18a and T176 set ups look like next to each other (the T176 on the right is the 6cyl version, T18 is the V8 version with bell housing adapter).

Installation

I start by removing the existing T176 and NP208. I unbolt the tcase adapter and free the tcase. It swings down and I'm not sure what's tying it up when IT FALLS ON MY HAND!!!! Ouch! Lucky I folded up a blanket to soften the blow of the tcase when it fell but like an injured athlete that returns to the game after a devastating injury, I press on! {ok, I know that's a little dramatic}. So I removed the existing gear boxes and install the clutch and get ready to install the T18. My jeep is basically stock so the only lift is in the tires, 1" maybe, so the jeep sits very low to the ground. I struggle to try and get the tranny up, thru the adapter, throwout bearing and clutch but after an hour I give up and call a buddy to help. So he gives me a hand and we bolt up the T18 no problem. I also put on the shifter and starter. Strangely, when I press the clutch, the pedal goes to the floor without pressure? Oh well no problem, I'll start her up and see what happens. CRUNCH, CRACK! I turn the key only to hear terrible noises from below! I look down there and see that the throwout bearing fell off the clutch fork and broke thru the bellhousing!! ARRGGGG!!!
I'm pissed now and pull the T18 and bellhousing. Fortunately, I had another bellhousing to use. I install the second one and in a gutty effort install the T18 again, alone this time because my buddy had left a while ago. I placed the tranny on my legs, lift, push and it goes in!

With the transmission and tcase bolted up I then go to install the gas tank (which was removed earlier for more room to work). This is when I learned WHY this set up was ONLY offered in the J20, it's too long for the Cherokee and Wagoneer FSJs!!! The chero/wag gas tank is the "coffin" style that runs along the inside of the driverside frame rail and is 51" long. There was only 50" between the back of the tcase and the rear axle. I then re-drilled the mounting holes to move the gas tank back 2". The front of the tank is against the NP208 and the rear is 1/2" from the axle. Not pretty to say the least but it's least drivable.

Plans are to install an aftermarket gas tank behind the rear axle to eliminate this problem and a couple sources I am aware of are Aero Tanks http://www.aerotanks.com/ and NorthWest Metal Products http://www.nwmp.com/

Here's a shot showing the T18 to 208 adapter and another adapter to extend the crossmember to the tranny mount.

When I finally have everything bolted up and installed, I turn the key and no surprises this time. I take the driveshafts to the machine shop to have the front lengthened 9" (37") and rear shortened (29"). I fabbed an extension to the tcase shifter linkage but still need to customize the e-brake and get the speedometer to work.

In conclusion

After driving the jeep for the last 3-4 months, I have to say I am extremely pleased with the swap. The ordeal was difficult at times but was well worth it in my opinion. With the 33" tires and 3.31 gears, I start out in first gear 90% of the time if at a complete stop. First gear is short and my top speed is about 7-10 mph. I view the swap similar to regearing the axles for larger tires, I obtain lower gearing for the 33's but don't lose anything in 4th gear for highway driving, I'm able to keep rpms down.