Anybody have an opinion on whether I should change to the solid pinion spacer? (Original 67 SS 350 12 bolt posi)

 

Are you setting up the rear or is someone else. If it is someone else I would go with what they recommend. If you plan on doing it yourself and you have never done one before, think twice about it. It is one or the two biggest redos that I have seen from DIY'er. It is not super complicated, but it is very unforgiving. Meaning even the smallest mistake your rear end up needing completely rebuilt. In many cases with more damage then that drove the original repair.

The crush sleeves are once and done and just about anyone that works on rears can install them. With the hard sleeve you need to calculate the near perfect preload length. I have never done a solid sleeve before, but I assume it is time consuming. Unless there is another way I assume you mount up the rear with a bigger shim and check the preload. Then keep going down in shim sizes until the preload is right. With a crush sleeve you just keep tightening the bolt until you get the preload correct. So the crush bushing is the factory recommend process but in theory if you ever remove the pinion nut you need to replace and reset the bushing. The benefit of the solid bushing is you can take the pinion back out and back in and it does not need reset assuming you replace none of the parts that make up the pinion assembly.

IMO is the only thing the solid bushing gains you is you can replace the pinion seal without resetting anything. I assume the solid bushing would come with instructions and specs. If the pinion seal does not last 10 years then something else is going on. If you get the soild one make sure you find a good place to store the extra shims. If something goes in the rear and you need to replace a part (pinion or bearing) you have to start all over with the shims. Maybe if you had to tear down rear to clean out mud or something it would be worth while?

 

I have never done a rear end. I bought the car in 1995 and have never had it running so I don't know how it was doing. Since the car is on the rotisserie I have the rear end on a set of jack stands. I pulled the cover to inspect it. It seems to be in pretty good shape but the pinion seal was leaking and of course I can't tell the condition of the clutch packs. I am thinking that I may just replace axle wheel bearings and seals as well as the pinion seal, get the car back together and then see how it does. So, I watched youtube guys replacing pinion seals without pulling the pinion out and that doesn't look too bad a job.

 

Just keep in mind the whole replace the pinion seal without a new crush bushing is not a factory recommendation. It is simply a lets try it type thing. There is nothing about the process in the factory manual. According to GM if you need a pinion seal you need to reset the rear pinion preload.

I believe most guys that do this mark where the bolt is with paint or some types of marks. The problem they teach in in class is the once the bushing releases its pressure its not the same when you re-tightn the nut. IMO how much that changes is a luck of the draw. I have seen a lot of guys follow this process and never have an issue on a car that have seen track time. I have also seen people have issues within 3 months of normal street driving with failed pinion bearings.

At the dealer I remember our service manager telling people that if its not dripping in your garage and you can make it between oil changes with less then a 1/2 a pint of lose then just leave it alone and remind us and we will check it every oil change. and if you want to show it just wipe it down before every show.

 

Only if the pinion ends up too tight after a seal replacement, do you have to worry about crushing a new sleeve
And at that point you should be considering new bearings