The Replacement Trunnion and Pin for Reese Trunnion Style Weight Distribution part 58098 fits into the Weight Distribution Trunnion Style Head, part # RP58167. view full answer...
Part # 58098 is the correct part as long as the spring bars have the curved end that connects to the chain. I spoke with my contact at Reese and if it is a curved end spring bar, it should fit the new trunions.
Since one of your trunions has broken, I would suggest replacing both. The second may not be far behind the first. view full answer...
You should be able to go to the 600 pound weight distribution spring bars with the Replacement Trunnion and Pin for Reese 600 and 800 lb Trunnion Style Weight Distribution, item # 58098. As long as the end of the spring bars that go into the trunnion head are 1-1/8 inch square this should remedy the problem you are having with twist. You may need to adjust the angle of the weight distribution head somewhat (see instructions link) to get the chain setup to your liking. view full answer...