T-18A vs. T18 Behind a 304 V8...

I have a '72 CJ-5. I have a 304 - T15 - D20 with a 4.56 rear end running a 32" tire. (27:1)

I am contemplating pulling the t-15 in favor of a T18A for the lower gearing as what I have now is to high for the 3+ trials I run in Moab.

I have a line on a T18a w/ d20 TC for $300. However I have read a lot about this conversion and realized that my bell housing is too short. So now this $300 is adding up as I need probably a new clutch, fork, and my drivelines recut not to mention a bell housing I can't find for under $200 plus having to do some minor cutting to the tunnel. This is starting too almost become much more than what I want to do to my very original '72. So the question is, would I be better off getting a Terralow kit ($1000) slapping that into to the TC and calling it good? Or should I go through a tranny swap all for an unsyncroed 6.32 1st gear?

One more note... I also know where I can find a '73 T18 (not sure on price the guy thinks its a T18A) 4:1 1st that would bolt in using the adapter that came from the factory, (It might have the tunnel there as well). Should I grab that T18 instead, pay a few less dollars and skip the bell housing and clutch work? Or can I grab the '73 adapter and then get the T18A and bolt it in because of the factory adapter? Will that work? Too many choices not enough money...

Thanks is advance.

 

I think you've got some terms mixed up here.

The designation T-18 and T-18A doesn't really tell you much. There's a wide ratio (WR) T-18 with a 6.32:1 1st gear, and there's a close-ratio (CR) T-18 with a 4.02:1 1st gear. Both of these transmissions have a non-synchro 1st gear. The original Jeep T-18s in their trucks were called T-18, but then Jeep introduced the CR transmission, and started calling the CR trans a T-18, and the WR became a T-18A. So all CR transmissions are T-18s, but the WR can be a T-18 or T-18A.

Jeep used the CR T-18 with 6 cylinders from 1971-1976 in the CJ-5. Not sure about the 1971 version, but the version paired with the 258 used the T-15 bell and a plate adapter. There's a WR T-18 that was available in the CJ-5 and CJ-7 from 1977 to 1979.

The usual transmission chosen for conversion to a T-18 is a Ford pickup transmission. These are all WR, and have a shorter input shaft than a Jeep CR (and some WR) T-18s. You can pair this transmission with the T-150 (76-79) or T-176 (80-on) Jeep bellhousing to adapt the trans to any AMC I6 or V8 engine.

There's lots of old posts about T-18 conversions if you search. JMO - if you can do your WR T-18 conversion for less than $1000, you're doing pretty well. Even the factory covers will require some floor cutting - the factory floors are a real prize (IMO) if you can get them.

Customers really liked the CR transmission with the 258, and it's really good for general trail riding, hill climbing, etc. To me, it sounds like you need a better crawl ratio, and a WR T-18 is likely the cheapest/easiest route to a significantly better crawl ratio - you'll double your crawl ratio over the T-15. Around town, the ratios are about the same, but it's more work to row a T-18 than a T-15... plus they are noisy. You'll have to cut the driveshafts regardless - the T-18 and T-14/T-15 driveshafts are of different length. Plus, with a V8, you'll have a non-stock trans/TC position regardless of which route you take.

hth!

 

Wow, your good! You got exactly what I meant.

I'll keep searching for the elusive local used bell; I'll go ahead and get that tranny. I have read a lot of your posts, and are you very well educated. I value your opinion. Thanks.

 

I have some real world experience, and learned the hard way.. Last year I installed a T18 4 speed in my CJ5. Best mod I have ever made.. Here's what I know now..

1. A Ford T18 is the easiest tranny to use as Tim noted. .. Find the one with the super low granny gear.. I cannot remember how to tell which one but I am sure someone here will chime in. I used a tranny out of a Jeep truck. I rebuilt it first and had a ton of issues.. You will not have those issues with the Ford tranny. Check out Novaks site for details and good info. Some people also try to use a Scout T18, but the mounting is a major hassle.. You will need the short input shaft out of another tranny or you can purchase one from Novak.

2. You will need a shorter Bell housing. I think it was a T150 Bell housing. I found a used one on Ebay for $65.

3. The modification to the floor pan is minimal.

4. Yes the drivelines need to be adjusted.

5. I purchased a rebuild kit off Ebay for ~$100.

 

According to Nickmil, the Sr-4/T-4/T-5 bell from 1980-on is the same casting as the T-150 or T-176 bell, so it can be made to work too, with some drilling. I think the retainer diameter is the same, but I'd measure the Ford retainer before I bought one.

 

I don't have a LOT of wheelin experience, but with my 4:1 first and in four wheel low, with 3.73's I'm crawlin' I can't imagine what it would be like with only changing to a Teralow 3.15 in the t case. Or even going 4.56 in the diffs with lockers.

Though, if you are doing rocks a lot, isn't an auto the way to go???

Good luck though, I seem to always see T 18's on Pirate and Ebay. Just keep your eyes open and you will find a deal.

High5

 

If I go Ford, I will need an adapter to go with my D20 correct? Plus longer shift rails as mine will be too short?

 

I can't recall what I did to mine.. I had a donor tranny that I got the input shaft and adapter from.. I'd check with Novak as it looks like you will need some kind of adapter.. I called Novak while doing my tranny and they were more than helpful. Another good source is Parts Mike..

Shift rails?? You mean for the transfer case?? I used the originals in mine..


Novak

 

If money is the issue, you can do the junkyard Bronco Dana 20, Dana 18 gear swap and lower your transfer to 2.46. A couple doner transfer cases might cost as little as $200. The required five gears by themselves are about $475 from vendors. No drive line mods, no shifter or floor mods. Transfer case comes off and goes back on pretty easy.
Better yet, find a Dana 300 from a 1980 Scout. Bolt on and the lowrange is 2.62!

 

I did the tera-low in mine. I'm running a 304, t15, d20. The teralow is great, and my t case was due for a rebuild anyway. With the 3.15 low, 2nd gear is now a tiny bit lower than 1st used to be with the old t-case, and 1st is a nice creepy gear. I'm runnung 3.73's wit 33"s and it crawls a little faster than what i want, but the tera low is the best mod i've done so far. I highly reccomend it. Dont be put off by the price of the tera low. Most dealers will get it cheaper than the $1000, i got mine installed for $900, the kit itself only cost me $650-700 IIRC.

Next I'm going for 4.88 or 5.32 in the rears, and that should put me where i want to be.

 

I dropped a WR T-18 from a J-series truck into my CJ for less then $600 including the bellhousing modification, short shaft kit and rebuild kit for the t-18.

I did all the work myself except for the bellhousing mod and it works great.

 

The above is true as I went with a bell and fork from a '84 I6/T4, drilled and tapped for a total of $20.

 

I found a Terralow kit locally for $800. They even have it in stock, I am really starting to lean this direction. Even if I could do the T18 WR for under $600 I might be ahead by going with the Terra kit much less work plus my TC has 150,000 miles on it. Might be worth the rebuild. The Terra Kit will give me 43:1, the T18 58:1.
Then if I ever do the T18 and the Terra 91:1.

I am awaiting a call from DC4WD. His website mentions a twinstick, Terra combo...
A Terra kit will give me a better gearing spread as well, in Moab it is not always the lowest gear you need, but just the right gear.

Thanks for all your opinions, you are giving me a lot to think about.

 

The terra low is a good choice. The nice thing is that since you already have a t-15 the same t-case bull gear gets used for the t-18. That makes the conversion a lot easier in the future if you decide to do it.

I have the combo you were thinking about. WR T-18, Tera low 20 and 4.56 gears. I regularly run around in 3rd and 4th gear while in low range. 1st and 2nd are for really rough terrain. 4th gear low is between 1st and 2nd gear high.

 

Quick question, I think I found a bell housing out of a 1981 Jeep J10 with an AMC 360 and a T-176 Tranny. Will this bell housing work for this T-18 WR project in my CJ?

 

I found this looks like it is what I already have.

* Early 70s T-18s use a 1" cast iron adapter with a deep AMC bell housing. The bell housing is the same as the bell housing used with the T-15.
* Later 70s FSJs with V8 engines use a 5" aluminum adapter and a AMC T-15 bell housing.
* Later 70s FSJs with I6 engines use a shoter aluminum adapter and a AMC T-15 bell housing.

 

That's not the whole story - the FSJ transmissions are different from the CJ transmissions.

However, (!) all that ends in 1979 with the passing of the 'great transmission' era. Jeep transmissions and transfer cases (mostly) were completely changed in 1980. Nearly all of their vehicles after 1979 got passenger car transmissions. The only Borg-Warner transmission that survives past 1979 is the T-18 in the J-20 only, and it changes to a New Process pattern with a DSD NP208.

I'm pretty sure the T-176 bell from a J-10 will work. The T-176 is a Ford transmission, so i will have the right engine and transmission pattern. To be 100% sure, you'd need to check the bell depth, but I think it's right. If I'm right, there's be a long stickout T-176 specifically for the V8 FSJ and a spacer between the bell and the trans, about 5" long.