Tractor Repair: 1977 Case 1070 with powershift, hand brakes, hydraulic problem

Question
1. I have a case 1070. The powershift works fine and seems strong, however, the other day, I was backing up in 2nd Reverse and as I was backing, the right rear tire suddenly locked up, causing the tractor front to skid to the left a bit.
I tried it in 1st and 3rd and although it does not lock up every time, it has occurred in those gears as well...but always the right rear tire locking up and only in reverse.
All fluid levels are good.

2. Also, is it usual for a 1070 to make a squealing sound in reverse?? It has always done so, at least as long as I have had it and I have read that the sound is the planetary.

Thanks for your help

Answer
Mike, you are having a hydraulic problem with your powershift...and that squealing sound is NOT normal. You need to have that checked out by Case. As for the tire locking, sometimes that is caused by wear to the right-hand brakes.....after awhile, they will bind......That tractor has some age on it...and probably plenty of hours, too, which would justify 1. It's actions, and 2. A good dealer-technician overhaul....Get it checked....because safety is always first. Good luck!