T5 to T4 swap

I hate to disagree, but it will work. We ran into this same problem during a buddies CJ-7 clutch install. We had to use his 14 spline T-4 from a 4 CYL, the

258 pressure plate, and had the auto parts place match up a proper disk (10.5 and 14 spline) Yes it was pieced together, but it worked, and continues to work fine. Option 2 is to swap input shafts between the 2 units...have to take them apart.

Shoot, if i have to take the t4 & t5 apart to swap the input shafts i might as well just rebuild the T-5 and keep 5th gear.

The closest i could come up with was a 9-11/16" OD 14 spline clutch from a 2.5L 4cyl cherokee..... but the pressure plate holes won't line up with the 10 spline plate (and those on the flywheel).

Don't want to run a bastard clutch setup, with a 6cyl pressure plate and a 4 cyl clutch disc.

Do you know what make/model donated the clutch disc referred to below??

and a 4 cyl clutch disc.

thats what he had to do.

make a disc,......

What are you talking about? Make a disc?? The auto parts store (O'Rilley) sells pressure plates, disc only, or the kits. We matched up the correct disc matching the thickness, material, brand, and outside diameter. The only difference was that it was 14 spline and not the 10 spline....We figured that the previous owner had swaped in a junkyard transmission (a 4 cyl unit). Also, jeeps run at low RPM's (under 3K) while a Corvette is high rpm and a fiberglass floor.... The combo we used worked fine and has not given him any problems.

I searched LONG AND HARD for a clutch that would work. i even checked the online centerforce catalog the other day which covered every darn make/model/and year back to ~1950 (there is over 1000 lines in the excel file). i checked a few friends that are all around pretty sharp on all autos, and they never heard of such a setup either. I read a reply from my similar post on CJ8.com and found someone who was running this setup, but he bought his 8 that way, and when his clutch died, he had to rebuild the disc. Basically i found i was S.O.L.

Onlyinajeepcj7: do you know what make/model disc your buddy used ? i am only curious at this point, since i have decided to move forwardin another route.

i wasn't about to run a bastard clutch setup. jeeps are great because they're CHEAP. the 10 spline clutch kit was ~$100 new. So the 14 spline T4 is down the road (even trade) and i am awaiting a ten spline T5 to show up at my house.

on the brighter side, now i have 5th gear again (though the gearing in my rear axle keeps me from really using it on the highway).

I can't wait to get my toy back on the road again. it's been an agonizing 4 weeks since this little "weekend" project began. i hate it when my damn job gets in the way of my toy.

Thanks for the help.

-brian

Brian,

I have been thinking about this for a while, and then I remembered that the old Direct Connection (Dodge) performance manual said it was OK to run a

10.5" disc with an 11" pressure plate. I agree yours probably isn't the optimum setup, but it can be done. I did find a 9-11/16" disc with that spline on it, which would leave about 3/8" per side of overlap on the pressure plate. For the most part, the loss of friction area can be compensated for by a slightly stronger pressure plate. I don't know the dimension of the "ring" of the pressure plate that contacts the disc, but given that information we could figure out the required increase in pressure needed to obtain approximately the same holding force. This is the basic concept with the clutches used in oval track racing. There are clutches used there that are only 5.5" in diameter, but with very high pressure plate pressures. The main reason for this is to reduce rotating weight and inertia for quicker acceleration/deceleration. This concept works in 500+ horsepower applications with a 2800 pound car. Also remember that these cars are under full power when they are accelerating and have approximately 10" wide racing tires that grip like the jaws of death. So if this is something you really want to do, it CAN be done with a little research and common sense.

Chris

i thought about that too... if i remember right from the other day, the clutch book said that 86(?) cherokees with the 2.5L run a 14 spline with hte 9-11/16" plate OD, which would leave with less contact area, however later down the road, replacing the whole assembly will be more costly, buying the pressure plate & disc separately, and way wear faster too, since there's less contact area, but a thicker disc would compensate for the time..... but it ended up working out for me, got a working T5 back which is what i started with.....

brian