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Manual Transmission conversion between years


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I haven't been able to find any threads that address my specific question so I am hoping someone with experience might chime in.

What changed between the 1990 and 1993 model years that might make it impossible/impractical to install a 5 speed manual transmission from a 1993 Cherokee into a 1990 model?

I started trying to answer my own question by contrasting the part number differences between the two on RockAuto and found that everything from the flywheel to the clutch to the Master cylinder is different. The parts look extremely similar (same tooth count on the flywheel for example). This surprised me and made me consider that this might not even be possible. Has anyone done this and if so, what 1993 parts worked and where did you have to go with 1990 parts?

The only changes in all the years was spline count and length.
The only changes in all the years was spline count and length.
So if we use all of the components from the '93 (pedal assembly, master cylinder, lines, flywheel, clutch, trans, transfer case and driveshafts) it should work? I don't recall if there is a clutch safety switch on the '93 but if necessary, I could fab something up to make sure the cruise control shuts off if the clutch is depressed

There is still going to be a lot of little things that need to be addressed.
The change you’re referring to is with the pilot snout. In 1992 it was increased to a 3/4” diameter. I forget the earlier model diameter. There’s some leeway with which 92 trannys actually have the larger pilot; I think it was a mid year change.

92+ ax15 will work fine on a matching 4.0
To pair an older 4.0 with the newer ax, you can use a pilot bearing from an early/mid 70s CJ with the 304. This is what I did on my ba10/5 removal/ax swap.
It sounds like the transition I am looking at should work then. The background here is that I have a mint 1990 with an automatic transmission and my brother has a rusted out 1993 with a manual. It sounds like I can just move all of the parts from the '93 to the '90 and then figure out how to patch the wiring for things like backup lights. Is the speedo interface the same? I know that the '90 uses a cable. Any chance the '93 either uses a cable or did they move to a sensor by that point?
I think the cable went out with Renix and the sensor came in with the H.O. system.

Here nick just swaps heads and manifolds but it’s essentially the same thing using any block. The main difference there will be the pilot bearing, you’ll wanna use the and renix flywheel as phydeaux mentioned. I just did this swap and the only other issues I came across were needing to get the throttle cable AND pedal out of the H.O. The nice thing is until you get to 1996/97, most of this stuff is the same, and the majority of changes were made in the 90/91 change. The donor being a 93 makes this pretty simple.