T-18 Input Shaft Diameter

[Rescue Diver]

I've read several different sites that say the input shaft on a T-18 is 1 1/8" 10 spline, but Partsmike.com says a Jeep T-18 has an 1 1/16" 10 spline. I checked Advance, Autozone, and O'Reilly's web sites and all three only list a clutch disc with a 1 1/16" inside diameter for a 79 Jeep.

Is it possible that the original Jeep version of the T-18 has a smaller input shaft than the Ford truck T-18 ? Is that why I'm finding conflicting info, or are Partsmike.com and the three parts stores sites wrong?

 

[CJ]

I have a 1 1/8 in my Ford T-18 . I just made sure to buy the correct disk for the clutch.

 

[Rescue Diver]

I have a 1 1/8 in my Ford T-18 . I just made sure to buy the correct disk for the clutch.

What I'm confused about is why do the parts stores only list a 1 1/16" inside diameter clutch disc for a 79 Jeep when the factory offered both a T-150 and a T-18 that year. I also wonder why Partsmike.com says the Jeep T-18 has a 1 1/16" input shaft? I need to find out if the factory installed "Jeep" T-18 has a smaller shaft than the Ford version? I'm starting to get a little bit of a Transmission collection at the house. As of a couple days ago, I have a T-176 that I can't swap in place of my T-150 because I have a Dana 20 Transfer Case . I just stumbled across an original 79 Jeep T-18 that I'm picking up tomorrow and am hoping I can use the brand new clutch that came with my Jeep.

The parts stores also only offer one pilot bushing size. I picked one up last night and it's the correct size for the T-150 . Others have told me the T-18 also takes a different bushing than the T-150 .

You wouldn't think it would be this hard to get this info. I guess I'll know what works after I pick up the new tranny tomorrow.

 

[CJ]

I screwed up! I just looked up my clutch disk and it's 1-1/16 - not 1-1/8. Also Novak say the input shaft is 1-1/16. -->> The Borg-Warner T18 & T19 Transmissions - Novak Conversions

What sites are saying 1-1/8?

 

[Rescue Diver]

I screwed up! I just looked up my clutch disk and it's 1-1/16 - not 1-1/8. Also Novak say the input shaft is 1-1/16. -->> The Borg-Warner T18 & T19 Transmissions - Novak Conversions

What sites are saying 1-1/8?

Thanks! That's awsome! I'll be able to use all the parts I already have!
My jeep even came with a rear driveshaft that's a few inches too short for the T-150 /Dana 20 combo. It'll probably work with the T-18 .

Jeepfan.com is one of several sites I looked at that said it's a 1 1/8" shaft

Jeep T-18 Transmission is a heavy duty four speed

"
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."

 

[Kane]

With my T-18 and chevy motor I had to buy the Ford clutch disk with the chevy pressure plat and fly wheel. The ford was 1 1/8 on mine and it is a stock Jeep T-18

 

[CJ]

With my T-18 and chevy motor I had to buy the Ford clutch disk with the chevy pressure plat and fly wheel. The ford was 1 1/8 on mine and it is a stock Jeep T-18

So much confusion! There were so many variants, who knows what to think, I guess the adage fits here, when in doubt - measure!

 

[Kane]

I was really questioning myself on this so I just went into the garage and checked my clutch centering tools for both he T-18 and chevy disks. The chevy tool measured at 1.085 which is about 1 3/16 and the T-18 tool is 1.070 which is about 1 1/16. They are both 10 spline and they are plastic tools so they might be slightly under sized but that does put my jeep T-18 at 1 1/6. Hope this helps

 

[Rescue Diver]

Wooooooot!!!!!

I now have in my posession, an ORIGINAL JEEP 1979 T-18 WIDE RATIO Transmission ! And better yet, it does in fact have 1 1/16 inch 10 spline input shaft so it'll work with the brand new clutch disc that came with the jeep. Even better, it'll bolt right up to my Dana 20 Transfer Case , as well as my original T-150 bell housing from the looks of it. My jeep even came with a rear drive shaft that was too short for the T-150 that it came with, but it should work just fine with the longer T-18 .

I'm set! This couldn't have worked out better. I even sold the T-176 this morning that I couldn't use because it wouldn't work with the Dana 20 .

I guess there are actually a few original Jeep T-18s left out there after all.

 

[CJ]

Fantastic! Your on your way!

 

[TDHofstetter]

Lessee. The Jeep T-18 had a 1-1/8" input shaft, the Ford version had a 1-1/16" input shaft. The Ford version has the same mounting bolt pattern (to the bell housing) as the T-150 , while the Jeep version's bolt pattern has one bolt in a different location.

You may need to notch the skid plate to clear the T-18 's drain plug.

How's your front drive shaft? Will it work out right?

There's work to do... but you GOT the prized Granny Gear Grinder!

 

[Rescue Diver]

Lessee. The Jeep T-18 had a 1-1/8" input shaft, the Ford version had a 1-1/16" input shaft. The Ford version has the same mounting bolt pattern (to the bell housing) as the T-150 , while the Jeep version's bolt pattern has one bolt in a different location.

You may need to notch the skid plate to clear the T-18 's drain plug.

How's your front drive shaft? Will it work out right?

There's work to do... but you GOT the prized Granny Gear Grinder!

I found a little discrepency with that. My new tranny definitely has a 1 1/16 input shaft that has been verified by sliding the new clutch disc from the T-150 over it, but it also has the bottom bell housing bolt higher on the passenger side, so it's an original Jeep T-18 . Not to mention that it has the texas bolt pattern on the Transfer Case side of the factory adapter.

Not sure on the skid plate yet, but I'll make it work. I have yet to check the front driveshaft length, but if it's a little short, I'll take it to the local shop to lengthen and balance it. It would be a small price to pay to have this tranny.