Bad U-joint or driveshaft 86 trooper

[chris741]

Hey guys, I bought this beast for $500 and it needed a major tune up and now that I have given it some new life, I have a clicking noise.

The noise seems to be coming from under the vehicle, possibly on the left and possibly in the rear. It is hard to tell when driving.

It's a single click consistent with the vehicle speed, not the engine revving, but when the wheels are moving. If this IS a U-joint or driveshaft problem, is it worth getting fixed? I have 135,000 and just do light driving in the snow a couple of times per week. I might find an isuzu dealer and try to get an estimate but what do you think is a fair price to fix this, if this is what it is?

Thanks