T18 input shaft length for jeep CJ

[rbdesse]

I have a cj T18 (T18-B casting) that I was told came from a 1975 cj-5. I also have the matching Dana-20. I think that the T-18 front input shaft is not the correct length, but I need confirmation. Does anyone have specs for the front input shaft.

I am building an AMC 401, and I have a stock T-18 bell housing (casting number 3229127 HI) with the required stud and clutch arm. There is no adapter on the front of the T18, and it is my understanding that the T18 bolts directly to the stock bellhousing which bolts to the block, so no adapter is needed. It is my uderstanding that the base of the flange of the front bearing cap is supposed to fit inside the hole in the bellhousing.

Here are the measurments on the front shaft (crude measurments with a tape measure):

- Front Shaft is 9 5/8'' long, distance from the top of the shaft to the base of the front bearing cap (mounting point on the transmission)
- Front shaft is 8 7/8'' long, from the top of the conical flange at the base of the shaft to the tip of the shaft.
- Front bearing cap is 5 3/4'' from the surface that mates to the front the T18 to the end of the cap
- The front input shaft extends 3 5/8'' past the end of the front bearing cap
- The front shaft has 10 splines on it, which are approximately 3'' long, and the shaft extends 1 3/16'' past the splines
- The front bearing cap has the casting number: 27-902

The problem I see is that the stock T-18 bellhousing is only 6 5/8'' deep, which means that the 9 5/8'' (minus the thickness of the front bearing cap flange) shaft will extend several inches beyond the bellhousing. This won't work, since the shaft is too long.


I have two questions:

(1). What is the length of the T-18 front input shaft (10 spline) that will work with the T-18 bell housing (3229127) and where can I get one (Novak?)? Do I have the correct one?

(2). The front bearing cap flange does not fit inside the circular opening in the bellhousing. I thought it would slide right in so that the transmission sits flat against the bellhousing. Isn't this how it is supposed to fit? Do I have the wrong front bearing cap (27-902)? Maybe the flange is an interference fit with the bellhousing, which will fit once the bolts are tightened? Any ideas? Does anyone have measurments on the front bearing cap flange diameter and inside diameter of the bellhousing (bellhousing to transmission side)?

Any help is greatly appreciated.

Thanks.

[Mudrat]

Don't know for certain, check the Sticky link in this forum Manual Transmission Info there is a lot of info sites listed there.

[msalaba]

Snip from http://www.novak-adapt.com/knowledge/t18_t19.htm


"Jeep T18
Jeep released 12 known versions of the T18 transmissions from 1966 and 1984, with the greatest variations being in input shaft configurations and gearing. The battle of working with these is compounded if you did not actually witness the transmission's removal from the donor vehicle.

Generally, most CJ T18's from 1972 to 1975 had the close-ratio, fitted with a front adapter plate in cast iron to the AMC bellhousing. These transmissions had the narrow ratio gearing (4.02:1 first gear). These 1972-1975 Jeep CJ T18's adapt to GM Engines with our #1415 kit.

1976 was a crossover year for the Jeep CJ T18, featuring either the 4.02 or 6:32 first gear and no front adapter as previously. Both these and all CJ T18's through 1979 had the shortest of the Jeep input shafts, measuring 7.43" of stickout.

All Jeep CJ's from 1977 to 1979 had wide-ratio T18 with the 6.32:1 first gear. No front adapter plate is present on these models. 1976-1979 T18 transmissions can be adapted to GM V6 or V8 by use of a T18 adapter kit that we manufacture, kit #1879. In 1979, the Jeep T18 underwent minor internal changes that affect the rebuild components used."


More T18 info here http://www.jeeptech.com/trans/t18.html

[rbdesse]

Apparently, there are a number of variations in T18 input shaft length.

I have learned that the early to mid 70's CJ T18 uses an adapter between the bellhousing and transmission; whereas, the late 70's CJ T18 does not use an adapter and bolts directly to the bellhousing using a shorter transmission input shaft.

In any case, I do not have a front adapter for my 1975 T18/Bellhousing so I must compromise. I need to know how far in front of the bellhousing (on the motor side) an AMC transmission input shaft "sticks-out".

Does anyone have a CJ manual transmission attached to the appropriate bellhousing (with any stock front adapters if any) out of their jeep? If so, please measure the input shaft stick-out from the end of the bellhousing and post it as a reply. This will help me determine the length of the input shaft for my application, as the stick-out from the end of the bellhousing towards the motor should be the same for all AMC transmission input shafts.

I would assume that the I6 would have the same stick-out from the front of the bellhousing, but I am trying to limit assumptions so I would perfer to see the stick-out for an AMC V8.

Hopefully, this is an easier question.

Thanks,

Richard

[tufcj]

I have a T-18 case and short CJ input (no adapter), plus a bellhousing in storage. I'm currently moving this to a shed at my house. If you can wait until the weekend, I can mock it up and give you some measurements.

This would be a 76-79 CJ setup. Memory says that the tip of the input shaft is nearly flush with or slightly recessed from the block mounting surface of the bellhousing. The reason being that the crank protrudes out past the mounting surface of the block, and the pilot bearing is flush with the end of the crank.

Bob
tufcj

[rbdesse]

Yes, I can wait. This is just what I was looking for.

Can you check to see if you have the same Bellhousing too? The casting number on the bellhousing is 3229127.

Thanks.

[tufcj]

The 76-79 (and maybe earlier) CJ bellhousing has a rectangular hole for the throwout arm. The 1980-up has a larger square hole. The 1980-up has a bolt pattern for the T-176, T4, and T5. It's missing a couple of holes needed for the T-18. I will check casting numbers.

Bob
tufcj

[tufcj]

Got my parts out of storage and mocked it up today. This is a known CJ T-18A.

Bellhousing is about 6 3/4" deep (couldn't find any casting #s).
Input shaft is about 7 1/2" long from the front face of the trans.
Bearing retainer is about 4" tall.
Input extends about 3 1/2" beyond the retainer.
Input shaft extends about 3/4" beyond the block face of the bellhousing.

This is the no adapter 76-79 CJ T-18.

I know CJ T-18s. Many years ago, when Wagoneer and J truck T-18s were plentiful, I got them at the local U-pull-it for $75. I could buy the CJ input and retainer for about $200, a small parts kit and bearings were another $100. Investment $375. I'd re-bend the shift lever to match the CJ T-18. Took me an afternoon to clean, disassemble, inspect, and re-assemble. I'd put them on eBay with a $600 starting bid, and some sold for over $900.

I got my parts from Mile-High Jeep Rebuilders in Denver. Their web site isn't much, but call them up, they do nothing but Jeeps. They may have the spacer/adapter you need.

You may still be able to get the CJ input for the 6.32:1 granny low T-18. I doubt you can get a shorter shaft if it's the 4:1, they weren't used without the adapter.


Bob
tufcj