What would make a 1995 Jimmy lock into gear for mos. & then suddenly release....then short while later, lock in gear again. Is there a way to fix it?

Check the steering intermediate shaft connection to the steering gear box, its slip shaft and the connection to the stering collumn. if those are ok, its probably slop in the steering gear box. Some of that can be adjusted out on the gear box by your mechanic. You will see either a flat head cut or hex head inset with a lock nut on the top of the gear box. Loosening hte lock nut and tightening the bolt to factory torque setting then releasing it the appropriate specified degress will reset the gear box back to factory settings. Beware if you set this wrong you will cause your steering to bind when turning. Therefore only let a qualified mechanic do this for you.

anytime anything electrical suddenly stops working, check the fuse. if blown, replace, if blows again, find the short.

Josh, same problem with my suburban, very frustrating. Two issues to check.
Underneath your distributor cap and ECM module there is the pickup coil. The reluctor is most likely corroded really bad. It is about one hour work but you would be surprised how dirty and corroded that area gets. The reluctor is a fixed part of the distributor shaft and the little nubs break magnetic field which is
processed by your onboard computer. If the pulses are not correct the computer is telling your TBI injectors to spray which will flood out your engine. Ten of fifteen minutes later, it will start up again and then die shortly after. Have a new pick up coil on hand too ($10.00) since your in there. My reluctor looked like it was in Vavy Jones locker it was so crusty. Second- the fuel relay. Nororious for developing little cracks on the mini circuit breaker which get wider as voltage and amps increase due to resistance (dirt,moisture). The relay will shut off the fuel pump if the oil pressure signal gets cut, and if your breaker/circuit board is
bad the board heats up and trips off your fuel. When the board cools off in ten or fifteen minutes, starts up and then dies when engine gets warm/hot. It really had me stumped for quite some time. Hope ths cuts your wrench time down considerably.

Check for a switch on the brake pedal lever. The part releases the gearshift when you put your foot on the brake pedal. A drivers foot often hits this switch and causes the problem.

For the rest of your problems they may correct when you work on the brake pedal switch. Or you may have damaged electrical system by shorting the brake pedal switch.

The plastic gear inside the motors gear box is probably striped here is a site so you can see one.

http://www.canadapartsonline.com/search/?PN=9328&VN=4294966393+4294966373+4294967261+4294967247+4294966352&Nf=price6'GT%20.01&N=0&Nr=universal:0

Hi, It may be in LIMP mode.

What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

Common failures on 4L60E, symptom any possible repair:

Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmission is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the under-hood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD and locks the converter :ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Car goes into gear but feels very sluggish like the brakes are dragging, but it will roll easily (starts out in 4th gear), you manually shift to 2 to get it moving, once it's moving you put it back in OD and the car shifts 3rd to 4th on its own and locks the converter at the appropriate time: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Trans seems noisy when moving in 1st and Reverse, noise goes away instantly if you shift to N or the trans goes into 3rd gear: Reaction planetary is worn out due to high miles or insufficient lubrication. Not a critical failure, but not a good sign either. R&R sooner rather than later.

3rd gear starts, can manually shift through all gears. When car has been turned off for a bit, then back on it will run normally.: VSS dropoff w/ Hi-stall converter. The rpms are too high, but VSS is showing no movement. Happens after a tire burning take-off. Doesn't store a code, will not throw a CEL (I've heard that it will store a code if it happens 3 or more times). Cure: Reprogram PCM for VSS dropoff -- PCMforLess knows about it.

If you can get the Jimmy for no more then $500.00 and the engine sounds good and body is good, you may want to invest in the repair of the jimmy. Also note that to have a close look at the fuel line along the frame on the drivers side just by the back doors, the line is know to corroded there on all the SUV's

Directly under the key lock cylinder is a hole. It may have a plastic cap in it, if so it just prys out. Take a tiny screwdriver push in hole while turning key backwards it will release switch & key.

Go to your local auto parts store and purchase a repair manual with the wiring schematic in it. It will show you the exact wire you are looking for. When replacing it purchase the same guage & color wire so there will not be any problems or confusion if later repairs are needed.

possible loose ground wire somwhere on engine

could be the fuel pump ...you will need to do a fuel pressure test on it ..the pressure should be 63 anything lower even so much as a few lbs will cause this to happen ...as well if it sat that long i would consider a complete tune up and check all vacuum lines for dry-rot