Trans swap help

I have a 1970 CJ5 with the 225 and a T-14 trans. The trans has been abused by a repair shop and I wish to replace this box with a 4 speed. I would like to keep the model 18 transfer case. I understand that the T18 willl bolt in but am not sure what else is required. Drive shaft length, mounts etc. What is the best trans to use and what length input shaft should I be looking for? This is my first attempt at Jeeping, Thanks Mike

 

I thank you, I am totally new at Jeeps and find the trans to be one of the most confusing subjects I have come across. The reason I was leaning away from a rebuild is that this tranny was rebuilt and screwed up as a result. I do not know what damage was done.
I had hear that the four speed was a virtual swap so it interested me with the 4:1 first gear.
I have come across a T-18 with a deep bellhousing for the I6 engine. It has the Dana 20 box on it which sounds like a easy swap back to the nodel 18.
My wife and I plan on towing it with our motorhome, occassional trips to Glamis in So. Cal. and just some easy trail work. I thought 1st gear was a little tall for starting out without slipping the clutch to start.

 

sorry about the poor proof reading on my part

 

I have a t18 in my jeep. and it was from a jeep and had the same adapter. As long as you have the big bore dana 18 transfer case it should go fairly simple. You will need a slight modification to your existing bellhousing, and need to modify your transmission mount. You may need to have the driveshafts lengthened or shortened, But I am not sure as to the length differences between the t 18 and the t14. I think it was one of the best upgrades I did on my jeep. I am surprised I am surprised Nick hasnt been on this thread yet. he has alot of info on these jeep swap stuff. Good luck

 

Hello Mr. 8084 - the T18 you are looking at will not easily bolt up to the V6. The bellhousing pattern for the inline 6 (232, 258) is different from the V6. Using your existing bellhousing with that transmission is possible, but may require some machining. I would not advise going that route if you aren't experienced. Plus, the T18 from a CJ with the 4.02:1 first gear is specific to that vehicle, and is considered less desirable for a swap than a T18A with a 6.32:1 from a Jeep or Ford pickup. I can elaborate on this if you like.

This topic is confusing, since there's no one location for the information you need, and because Jeep mixed and matched quite a few different engines, transmissions and transfer cases.

The simplest 4-speed swap is the SM420 because it is a GM (Muncie) transmission, and it will bolt up to the V6 bellhousing easily. That means that the bell pattern is right, and all the clutch components are compatible. It's not the cheapest route, since it requires that you buy an adapter to go between the transmission and transfer case, but it requires less knowledge and experience than some other transmissions.

I don't know what your level of experience with cars is, but I'd guess you'd be better off fixing and/or replacing the T14. We can give you some good contacts if you want your T14 rebuilt (Herm). Certainly you'd be way ahead in terms of costs. No transmission swap is going to be as cheap as repairing the T14. Your complaint about having to slip the clutch is unusual. The V6 has a very heavy flywheel, and lots of torque, so it should start off easily. Plus, starting off in first with a T18 (or any of the heavy duty truck transmissions) is very unusual. Typically you'd start off in second - first is only used for crawling over obstacles or pulling heavy loads.

hth - welcome from Boston.

 

Yup he pretty much covered it.. I have the SM-420 which required an adapter to the transfer case ($500 at novak). Anyhow read over the knowlege base at www.novak-adapt.com it has a lot of good info on all the transmissions involved.

BUBBA

 

A T-18 fits behind a a Dauntless very easily. Reference: the Novak Knowledge base for info on adapting a T-18 to a GM engine. The Jeep T-18 adapts in a similar manner, but one bolt hole is in a different spot and you will want a shorter input shaft and bearing retainter if you have a long or intermediate input. I'd use a Ford input shaft and bearing retainer from a T-18 of similar age and with the same 1st gear ratio and tooth count on the input gear. Swap the Ford input in, and have the input bearing retainer turned down to the chevy dimensions - as outlined in the Novak article.

Ford 2wd T-18s go for about $50 in my area, and the U-pull yards always seem to have some if you can't find one elsewhere. If your Dana 18 doesn't have the large hole case, swap the guts into a Dana 20 case - also very cheap in most areas.

There's lots of other info on this board about the T-18 swap as well.

Before you perform this swap, you should know that a T-18, SM420, NP43 or Sm465 will all shift like a 1 ton truck from the '70s - becuase that's what these transmissions were originally used in. These are all very strong transmissions compared to a T-14 or T-15, but they don't shift like a car.

 

Thanks for all the good info. I may for simplicity sake rebuild the trans for now. Appreciate the help, Mike

 

As stated above, this is not an unusually hard swap. I really dont understand why everyone is pushing you away from this. If the bellhousing mod is more than you want to do, go thru advanced adapters and purchase the bellhousing, and the clutch assembly and it is a direct bolt in. As for being hard to start off in I dont have any problems with mine. i really like the first gear. Too low for normal driving, but a great crawl gear for off roading. I am telling you from experience, not from something I read, that in my opinion it is a great swap, and a big upgrade to the small 3 speeds that came in these. I dont understand why everyone pushes for the 420, or 465 because they both require a transfer case adapter, and if length is an issue, the t 18 doesnt need an adapter to make it work, just some simple machining.

 

Chris, you're right - if you have a T18A from a full-size Jeep and use the short input shaft and bearing retainer from a Ford, the T18 is an easy swap. Those parts are available from Parts Mike at reasonable cost. I understood this is what JNutter was suggesting too ... but I don't think the T18 from a CJ with the 4.02:1 1st gear is what you want. This, not the T18A, is the transmission Mr. 8084 was asking about. Not the same. You can't use the Ford short input shaft with that transmission unless you change all the gears. Plus, you get the 4.02 1st gear, which isn't as desirable. The CJ T-18 is also longer than the T18A with the Ford input shaft, which means shorter drive shafts. And, the CJ T18A is used with an AMC-to-T15 bellhousing, which may or may not be easy to adapt to a V6 bell - I don't know.

The SM420 does have a few advantages over the FSJ T18A, including no machining at all, and a somewhat lower 1st gear. I'd agree, that if you can find the FSJ T18A for a good price and can handle the minimal machining needed, the T18A should be a cheaper swap by $200 or so, and only slightly more difficult than the SM420.

Sorry I'm rattling on here - hope I haven't muddied the waters.

 

please dont get me wrong, it is just that I found alot of resistance to using the t18 when I first decided to use it. I agree it is alot simpler if you get the RIGHT t18, but I found it alot easier to find the t18 I needed that was adapted from the factory to the d18/20 transfer case, than to go thru the extra expense of all the adapters and the added length of some of the adapters with other transmissions. I am a big advocate of the t18 with the 4.00 first gear. Easy to come by and most of the time when you use first gear you are in low range anyway. I am not a rock crawler so the super low gears arent a factor for me. I am still running 3.73 gears when I have a perfectly good set of axles with 5.38. I recommend just looking around and finding what you have accessable and working with it, My only point is just not to be weary of the t18, it is a very strong gearbox, and I am very happy with it. And spary, I dont think you took my post the right way, It wasnt meant to mean mouth anyone, but as you stated, just voice what "I" would do. Good luck with whatever you decide and as always ask alot of questions ,here there is alot of old and new info floating around here.

 

The other option for the T-18 with intermediate or long input or any T-18 with a 4:1 gear set is to get a Ford 2wd T-18 with 6.32:1 first gear, drill and tap the rear of the Ford case to accept the Jeep D20 adapter and swap the Jeep output shaft into the Ford case. Oldjeep did this with his Dauntless/T18 swap and it worked great.

 

I have the 1970 w/ 225 like yours. I had the T14 and swapped it out for the SM420. I would not recommend doing this until after you get a bit more experience. That's just my opinion. YMMV.
There's a ton of good info on the Novak site - check it out.
The T14 I took out is in good shape and I would sell it to you but the shipping would be $$ from Alaska.
Good Luck.