Where is the transmission fluid check on a 1990 jeep wrangler PLEASE

If you cannot find one locally rebuilt or new from the dealership, I recommend ordering one online. This company appears to sell your model, though I have never purchased from them before they might be reputable:
http://www.wowautoparts.com/1990/JEEP/WRANGLER/Transmission-Transaxle-Assembly/Manual-Transmission-4-Cylinder/7995.html

Sounds like a leaking master or slave for the clutch that is not permitting full disengagement. If it only happens when cold it could also be caused by incorrect lube (too heavy) in the transmission, but that is unusual.
Make sure the fluid in the clutch master cylinder is full and that there is no visible seepage where the rod enters from the pedal and that there also is no seepage at the slave unit.

On automatics you fill through the dipstick tube. On stickshift, there is a fill plug on the drivers side of the transmission case.

Most 90 wranglers from 89 to 95 have an ax15 5 speed transmission in them. The 4 cylinders had an ax5 transmission.

Sound like your clutch master cylinder has developed a internal leak or maybe even leaking out the back past the seals. Have you checked the brake fluid level in the clutch master cylinder resorvoir it may be low and you have air in the system. Either way you have a leak somwhere in the system and you need to determine where it is. Fill your resorvoir with approved fluid and while some one is pumping your clutch pedal see if you can see where the fluid is leaking from the jeep. Reair or replace as necessary.
good Luck

check passenger side of transmission - it is a 3/8 ext that will fit the bolt - does not really look like a regular fill hole -

The clutchless shifting doesn't help your cause any. Has the fluid been changed yet? Start with fresh fluid and go from there.

the plug of the transmission of 1992 jeep is under the transmission case .

Your Wrangler is a YJ and the model is an "S". A Wrangler manufactured in 1987 through 1995 are all YJ's and then from 1997 through 2006 are all TJ's. The new Wrangler models are dubbed JK's.

9 Degrees Application: With automatic transmission
With Federal emission
16 Degrees Application: With automatic transmission
With high altitude emission


9 Degrees Application: With manual transmission
With Federal emission
9 Degrees Application: With manual transmission
With Federal emission