If the ticking only occurs when the car is MOVING in reverse, then it's probably the dreaded reverse clutch plate wear. I don't know which transmission the later TE has, but the 722 series trans is notorious for this issue. The reverse fiber clutch plates wear down, the clutch basket moves too close to the housing and begins to contact it when the car moves in reverse. One other clue is that when shifting to reverse, it takes several seconds to engage the gear - it should engage in 1-2 seconds.
If those symptoms exist, you should repair it soon, as the ticking sound is grinding small pieces of metal off the clutch housing, and the plates are probably coming apart.

You should pull the pan and see if there is evidence of clutch plate dust or actual pieces of plate in the pan; that's a dead giveaway.

Replacing the plates is actually pretty easy -once the tranny is removed - they are at the front of the tranny, and only the front cover and pump need to come out to reach them.

Many guys recommend a total tranny rebuild if you are going in that far, and if you are paying a shop to do all the work, that may be the best approach.
But, it's a reasonable DIY job for a decent home mechanic, and the rest of the trans will probably last for years.

Check the easy things first as recommended in the earlier posts, but if you have the above symptoms, do a search herein for more info, lots of good posts about it.

DG