Hi all,
I'm considering purchasing a '78 Toyota Chinook (built on a '78 2WD long bed pickup chassis). I had my mechanic look at, and he thought that the rear differential needed to be replaced -- he determined this by just turning one of the rear wheels back and forth to see how much play it had before engaging the driveshaft. So I negotiated to have the seller get the diff fixed, but his mechanic says the diff is in great shape and has no problems, so I'm trying to figure out if I should press to have the differential (8" ring gear, 4.11 ratio) replaced before completing the sale.

How can I check this myself? Is rotating the rear wheel to check for play a good method? If so, how much play is acceptable? I've been totally able to get any sort of useful answer from google, so I'm hoping you can give some guidance.

I have a similar question about one of the u-joints - seemed like it might want to be replaced. How much play do you look for there before deciding to replace one?

Thanks,
George

 

Thanks, 50r -- I'd post a video, but the truck is an hour away now, and I can't make the trip out there immediately, so I was hoping for some quick guidance on what you'd look for. Anybody have any rules of thumb?

 

I remember seeing about 1/4 rotation of a rear wheel free play before the drive shaft engaged. Does that sound excessive?