I bought jeep comanche and it is only 4x2 , i really wanted to make it 4x4 without replacing auto transmission (stock trans from 1988 comanche) need some advices, it is 4.0l and 88 comanche - what jeep parts fit in this comanche???

 

You have to replace the trans if you go to 4x4. The only trans that was easily converted was the BA 10/5 5spd. All other transmissions require a main shaft and case swap to complete. Usually these are sourced from the donor vehicle.
As far as what will fit, the MJ and 4dr XJ are the same from the front doors forward. Suspension, doors, interior (with exception of headliner and seats/brackets). There are other small differences but otherwise most parts are directly swappable going by year/engine mgmt generations (even some later parts swap across.
My 88 MJ has a 2000 XJ front clip, 92 XJ blower motor, headlight delay, front door quarter Windows, hockey stick door handles, 1990 XJ ecm, Guage bezel, 1996 TJ power steering pump and brackets, 1999 ZJ intake manifold, 1994 XJ throttle body, and fuel rail, 1989 S10 2.8L tps, 1992 coolant bottle, 2000 XJ water pump and radiator (literally stock items off my 2000 xj) and a bunch of other crap I'm forgetting ... All on the stock Renix fuel system. Point is, a lot of cross compatibly.

 

A 2wd trans won't work with a 4x4 unless you gut the trans change the output shaft and tail housing pretty much rebuild the trans.

 

Find a 4wd donor XJ and let the fun begin