So I have a 94 pickup sr5 supercharged 3.4 swap lifted with 15x12.5x32 tires and last week the rear end took a dump on me. To be more specific, the pinion. I was having some power loss in the 3-4K rpm range so I took it to a tuning shop. Their only available mechanic test drove it and brought it back on its last leg. Not sure what this guy did but he said hey man your diff sounds bad. It wasn't like that when I took it there. Well long story short, I was charged 100$ for diagnostic fee and the guy couldn't even figure out why I was loosing power and they wouldn't take the blame for the axle. I get the truck home and pull the third member out and the pinion is missing two teeth completely. The ring looks ok with a small chip off the end of one of the teeth. I'm the second owner of this truck and some mods were done before I owned it. So now I'm trying to figure out what ring and pinion I need to replace this. Also it looks like there is a locker in the third member. The ring tooth count is 39 and the pinion tooth count is 8. If my calculation is correct, that's not a very good ratio for a truck with slightly larger tires on it. I don't want to go to a different setup just because I don't want to pull the front end off and change the hearing on that as well. Can anyone help me with this issue?

 

Well 39÷8 = 4.875 so you have 4.88 gears.

Pinion is shot so you need new gears.

 

The 4.88 ratio should be just about right for 32" tires, given that Toyota shipped stock with 4.56 and 31" tires. Especially with the more powerful engine, 4.88 is not too low by any means.

 

Thanks for the reply! I really appreciate the clarification

 

Hi Steven-
Those were Richmond gears and that's an old Truetrac or something for the limited slip it has. Probably put in there back in the late 90's. If the pinion broke then I tend to say it's a gear set-up issue.....especially after seeing the wear pattern along the edges.
Ken