Have you checked the fluid level? I had that problem with my CJ7 years ago, turns out it was low on oil(30w not gear lube!) I replaced all my trans and dif. fluids with Royal Purple on my last Wrangler, best decision I ever made.
Yes. Check that first. Beats knowing for sure it needs a rebuild because you didn't.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.