need help with cj info

cburgin

Well-Known Member
Joined
Mar 20, 2005
Location
statesville/boone NC
just found a good running 78 cj5 with the inline 6 and a 4spd. i havent driven it yet so my ? is would the tranny be a t-18? i think that it is but wasnt sure of the first gear ratio in the cjs? he only wants a $1000 for it. it is well worth it other than im wanting a 304. anyone have any info in the tranny?
 
cburgin said:
just found a good running 78 cj5 with the inline 6 and a 4spd. i havent driven it yet so my ? is would the tranny be a t-18? i think that it is but wasnt sure of the first gear ratio in the cjs? he only wants a $1000 for it. it is well worth it other than im wanting a 304. anyone have any info in the tranny?
Click to expand...
It should be if it is the original tranny. the T18 has 2 first gear versions. the T18 has a 4:1 and the T18A has the granny 6.32:1.
 
It is possible that the tranny has been changed. If the first gear feels low, then it is certainly the T-18 or T-18a. If it feels like you have to use first to take off it's most likely a T-176
 
Also, the T-18 or T-18a has an unsynchronized 1st gear. Very noticable, especially on a downshift.
 
Plus, right hand side will have T18 cast into it 90% of the time. Take a srewdriver and scrape the gunk/crud off. "A" is the goldmine version.
 
Hey,

the t18 i have in my CJ came out of a '78 CJ5. technically it's a t18-1b, but it has the granny gear ect. it'll be very very obvious if 1st gear is a granny gear. i was thinking that the regular t18 with the 4:1 1st was only used in the early 70s, like '72-75' maybe???

later,
bigmac
 
The T-18 is a heavy duty four speed with unsynchronized first gear. These transmissions were manufactured by Borg Warner and they have a cast iron case. The casting number on the drivers side of the T-18 is T-18 or 13-01. The T-18 has a 1 1/8" 10 spline input shaft and a 1 3/8" 6 spline output.

The T-98 has a very similar appearance to the T-18 except a casting number of T98. It is heavy duty like the T-18, but a bit more prone to wear since bearings and lubrication are not as good. Internals from a T-18 can be put in a T-98 case. The T-98 has a 1 1/16" 10 spline input shaft and a 1 3/8" 6 spline output.

T-18's used after 1978 have reverse down by fourth and earlier T-18's have reverse up by third. The shape of the case is also different with the '79+ cases for the different reverse configuration. Both versions have a PTO port on the drivers side.

The T-18's used in full size Jeeps (FSJ's) such as the Cherokee, Wagoneer, and J-series pickups use a transmission to bell housing adapter. Three basic versions exist.

Early '70s T-18's 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 FSJ's with V8 engines use a 5" aluminum adapter and a AMC T-15 bell housing. This is the one that I am using.
Later '70s FSJ's with I6 engines use a shorter aluminum adapter and a AMC T-15 bell housing.
The different adapter means a different length input shaft is used. The input shaft size and spline count is consistent for all the Jeep T-18s, but the pilot bushing size varies.

All Jeep T-18s come with a 1" adapter for the Dana 20 transfer case except the 1980 and 1981 J-20 pickups. These trucks used the NP208 transfer case and the adapter for the NP208 is about 9" long and it uses a round bolt pattern. The output shaft of this version of the T-18 is 23 spline. The Dana 20 version of the T-18 has the big hole "Texas" bolt pattern and 6 spline output shaft.

Trans 1st 2nd 3rd 4th 5th Rev
T-98 6.40 3.09 1.69 1.00 N/A
T-18 4.02 2.41 1.41 1.00 N/A 4.73
T-18A 6.32 3.09 1.69 1.00 N/A 7.44
 
77-79 T-18 was an optional 4 speed WITH the 6.32:1 low Firstgear. the 4:1 were the earier model T-18's that came that way from teh factory. So if the tranny is original in that CJ from the factory, you have the (or at least should have, I'm not gonna second guess what tricks AMC pulled on a rainy tuesday instead of a sunny Friday) the Granny low T-18. ignore the part about T-18a vs B.... there were as I found when getting mine, some 16 versions of the T-18 between Ford Jeep, IH and whoever else used them.

btw, just a note: T-176 wasn't standard until 1980, it bolts to a D300 and is an aluminum case.

If that's the original T-18 from 1978 in that CJ, you have the rare sout after Late model CJ t-18. Good find!
 
so just to make sure. there were no other 4spd options in 78 behind the I6 right? because i am about 99.9% sure that this jeep is all original. i guess i just need to get down there and drive it, i had to put it off until this weekend. im sure i will be able to feel the granny low of the t-18...
 
Back
Top