I would like to do this to my CJ8. I currently have the sr4 tranny and have to hold it in 4th gear. Was the swap pretty easy? Did you have to order new drivelines? Would love some advice.
Swapping with the TF-999 made things easier. I believe your SR4 is the same length as my T-5.
I was able to use the same unmodified driveshafts.
I used a Lokar shifter and Lokar kick down cable. I removed the clutch pedal and kept the existing pedal assembly.
You will need the flex plate and crank bolts and a flex plate reinforcement ring.
I also had a radiator with plugs for auto transmission coolant lines and used lines from the donor transmission.
The skid plate and transmission mounts worked with minor adjustments.
You will also need the automatic solenoid.
It was a good swap and I like the change. You might want to verify your axle ratio to see how the change in gearing will effect the change in gearing with the 999.