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From the inside its hard to tell but when i take off all the way through first gear i have clunk/grinding noise. I looked at the out put shaft from the tc and there is play where it goes into the tc. the front u joint though doesnt have any play. also my rear drive shaft got torn up a few weeks ago the rear rubber seal is completely ripped off but i had some one stand out side when i took off and they confirmed it is coming from the front. all help is greatly appreciated. The clunk goes from constant to only once when 4wd is engaged.

You might also look at the trans my 86 made the same noises and that is what I thought at first.
Then one day the tranny went out it was the 145 and did some research and the 145 had the problem of getting oil and keeping the first gear cool.
I don't know what tranny you have but maybe this will help I have put the 146 in.

Maybe axle gear oil is old? I had a pop/clunk on my rear axle and draining and filling the gear oil in the rear axle fixed it.