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T18 in a CJ5?

8K views 21 replies 15 participants last post by  CJ51973 
#1 ·
I went out today with some experienced 70's Ford Bronco guys. I was in new territory and they took me up some steep hills (at least seemed pretty steep climbing them). My little CJ5 performed well but I definitely need to get a lower first gear for crawling. My t-15 just isn't low enough. I am told the CJ5 won't easily accept an auto so I am thinking a 4 speed is the best option. T-18 or 18A.

Will a T-18 bolt up to the Dana 20 fairly easy
 
#2 ·
The bolt-up to a D/S20 can be quite simple if it came out of a CJ. The issues lie in having the proper bell housing, drive shaft length(s), and possibly a tunnel added to the floor area for clearance issues. With some decent fab skills and a drive shaft shop nearby you could pull it off.
 
#3 ·
The Dana 20 is original on the CJ-5. I also have one from a J-20. I guess the bellhousing is the only thing I am unfamiliar with. Driveshaft and tub mods are no problem. Time to do some homework.
As puckered as I was climbing those hills I am ready to go do it again!
 
#5 ·
As mentioned above, if you can find a T18 out of a CJ you're golden.

The confusion arises when people try to use a T18 out of a ford truck. That's when you have to pay one of the adapter companies some serious coin for adapters.

FT
 
#6 ·
The problem is most stock CJ T18's have the 4.0 to one first. This isn't nearly as desirable as the "A" model with the 6.3 granny low. They are also hard to find and fetch a premium price.
The 75 bellhousing may need adapting/replacing, as you probably have the T15 transmission.
My suggestion is a Ford T18, Novak or stock used mainshaft/adapter, 76 or later bellhousing from a 150/176 application. This will leave you with a fairly bolt in setup that may only require some driveline work and minor sheet metal adjusting.
The other option is a gear swap, however depending on your existing gears and what you opt for,, this may effect your on road drivability.
 
#10 ·
#11 ·
For the intermediate years you will need a T150/T176 bell housing. The T15 bell is the wrong bolt pattern. I went with J truck T18 and put a short shaft kit from Parts Mike. It was less $ than modifying a Ford T18. You'll have to lengthen/shorten drive shafts. All things considered a Teralow kit isn't much more and your driveshaft length is happier. 48:1 compare to 36:1.
 
#12 ·
'80 and newer Jtrucks with V8 got T18, but it's the Ford version with an extra long input shaft and a spacer between the trans and bellhousing. You can install the shorter input shaft, but they also are 31 spline with NP208 from a Ford attached (until recently I thought they were 23 spline like the other Jeeps)
 
#14 ·
The T18 is 11.87" long. Your T15 is 10" long. Not that the length of the transmission determines true driveshaft length (you have angles and stuff to deal with) but you're looking at almost a 2" difference. A local driveshaft shop can handle the shortening/stretching. If you use adapters, the extra length will have you shopping at Tom Woods for a double cardin driveshaft and the need to reseat your rear axle to an acceptable angle.
 
#15 ·
I'm not sure about the frame of a 75' CJ, but in 78' there is another hole in the frame towards the back of the Jeep to move the skidplate/cross member back to accomodate the additional length of the T-18. The T-18 was an option for 1975 so your frame may have the same holes in the frame to accomodate the length. Finding a T-18A from a CJ, while difficult to find these days, is not impossible. Next best thing would be a T-18A from a full size Jeep and install the short shaft kit. The T-150 bellhousing is the same for the T-18 and are relatively common.
 
#17 ·
Another option is a NP 435 out of a Ford. It will bolt up to an AMC motor but you will need an adapter for the tc. I did this with my 76. It has a AMC 360 and a model 20 tc. You would not be dissapointed with the performance. The transmission requires a new main shaft and adapter plate, so if you can come up with a T18 that will fit without mods you would be better off, but it is another option.
 
#21 ·
Yes, the NP435 is longer than the T150 that the '77 has in it so driveshaft modifications will be necessary. Don't rely on casting numbers on the case to tell you if it's a granny version or not. I have had granny versions stamped with 13-01, T18a, and T18b on them. I also have a non-granny version stamped 13-01. You have to put the transmission in first gear and count how many input shaft revolutions are required to turn the output one revolution. If the 4speed isn't installed this is easy and foolproof.
 
#22 ·
Driveshafts....if you just modify what you have it will be aorund $100 to shorten the back. The front will need retube so this will be more like $200. If either need replacing then more. I had to have a front made and I think it was like $350. It's been a while so others might have newer pricing.

So if you factor the bellhousing ($100), Driveshaft ($300), Transmission ($200), Short shaft kit ($200), Clutch ($100) you end up around $900 and that hasn't paid for oil, gaskets and other misc. A Teralow kit is like $850. It doesn't come with all the bearings you need but it does have the gasket & seals. I have all the Timken numbers for the Dana 20 bearings so you end up at about the same money without the driveshaft angle issues and transfer case shifter issues (it ends up moving back toward the seat which will require something to be fabricated).
 
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