Good to have tools for your planned projects, Alberto! Your photos could answer the limited slip question if we brighten up the diff pictures to show whether there are friction discs between the diff case and the axle shaft side gears. The "missing" lock pin retainer on the pinions or "spider gears" shaft is very important, as this lock pin holds the pinions/spider gears shaft in place.
Warning: If the pinions/spider gear shaft works its way out on a C-clip design axle, the axle shafts can slide inward, C-clips drop loose, and the axle shaft(s) can slide out the side of the vehicle. This results in severe damage or an accident due to loss of vehicle control. On both the C-clip and non-C-clip axles, if the pinions/spider gear shaft slides out, it can destroy parts or even cause axle parts to seize. The rear axle could lock up and cause a severe loss of vehicle control and an accident.
According to the 1989 factory service manual (U.S. edition), your rear Dana 35 axle should not have a C-clip design axle. You should have press-on axle shaft bearings and bearing retainer plates at the outer tube ends of the axle housing. The retainers keep the bearings and axle shafts from sliding out of the axle housing, and the axle shafts with bearings are a snug fit into the axle tube ends. These "seal retainer" plates attach to the brake backing plate studs.
Some differential carriers (typically those with C-clip axles) use a retainer bolt to hold the pinion shaft in place. These bolts are notorious for snapping during removal. This ends up a major problem, as the high tensile strength sheared bolt shank must be removed before the axle can be serviced. (I'll save this repair for when such a question comes up in the forums.) Most often, during axle shaft bearing or seal replacement service, the bolt snaps as you try to remove it.
In your situation, if this is not a C-clip axle, you should have a pinion/spider gear shaft "lock pin" and not a lock bolt. You may be able to install a new pin with the differential still in the axle housing. Access may be an issue, but this part is very important. If you cannot install the lock pin retainer with the differential case and ring gear in position, you will need to remove both axle shafts and the differential case with the ring gear to access the lock pin hole. First see if you can access the retainer pin hole without removing the differential case.
Here is the illustration of an "open" differential, not a limited slip. Zoom-in for details. (Your mouse scroll wheel may be necessary for this step.)...Note the role of the shaft lock pin, Mopar P/N S0455313. This may be a generic part number:
1989 Wrangler Rear Axle.bmp 7.52MB
If you have Trac-Lok, that differential also uses a lock pin to hold the differential shaft in place. Here are the Mopar part numbers for the Trac-Lok differential spider gear (pinions) shaft lock pin:
PIN, Retaining...83505019 (1987-89); 05252502 for 1990
You do need to take care of this lock pin issue right away, Alberto...