Np 231 t case noise

New to this - was wondering if anyone could help with what seems to be noise from the t case. I have a 91 yj with a 4" spring under, sye, tom woods driveshaft and recently I am hearing a ticking/clicking noise from driveline area. All fluids check normal, all u and cv joints seem ok, tranny shifts fine (5 speed man ax5). Is it possible for t case chains to stretch? Driving does not seem to be effected but the noise increases with speed of the vehicle and is more audible when in lower gears accelerating from a stop or climbing hills. Any help would be greatly appreciated - its a daily driver and I'm having nightmares of the t case and tranny getting blasted to pieces. Am I being paranoid? Thanks  

T-case noises usually present in a growl from a bad bearing or a buzzing from a worn chain.

Ticking noises, especially like you describe, are most likely U-joint related.

Put the vehicle in Neutral, e-brake on, chock the wheels, and crawl under. Grab the front and rear driveshafts close to the T-case and axle yokes and push/pull/twist them. You're looking for any play inside the U-joint. It's normal to perceive a little play because there's some backlash in the drivetrain, but what you're looking for is play between the U-joint body (trunion) and the caps that are pressed inside the driveshafts/yokes.

Sounds like bad U-joints to me. The '91 YJ should have 1310 front U-joints, but the rear could either be 1310 or 1330. The 1330 has the same cap size as the 1310, but the U-joint is taller at the crosses. Just FYI to help make sure you only make one run to the parts store. Or, you can buy genuine Dana/Spicer U-joints through places like Quadratec. Tom Wood's Custom Drive Shafts also sells a very good line of Gold Seal U-joints that I've used for many years with zero failure. Both Spicer and Wood's are my go-to places for U-joints.

Because of the lift, it could also be inside the CV. You need to keep them lubed about every other oil change. Failure to do so can cause premature wear. Pull the rear shaft and drive a bit on the front axle (be really careful if you have a front locker). See if the sound continues with the rear shaft out. Do the same for the front.  
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Thanks Hazel - will do. Love the magazine and go cover to cover every issue. Please keep the articles real as always. High end stuff is nice but I teach and work const. so I'm trying to get the wife to make the big $ otherwise upgrades are slow and cheap. As a reader I really like the fact that you guys often try to put in cost with upgrades - it helps in the decision making process alot. All of you do a hell of a job - thanks for the info.