Anyone ever mix rear end gears?

[Cranky]

And have them actually run quiet? The thought crossed my pea brain when I pulled a 3.55 pinion out of a chunk that had the diff missing. Probably had a SG and someone pirated it for another gear ratio. The original ring is long gone.....

 

[MoparMitch]

And have them actually run quiet? The thought crossed my pea brain when I pulled a 3.55 pinion out of a chunk that had the diff missing. Probably had a SG and someone pirated it for another gear ratio. The original ring is long gone.....

I've set up a bunch of rears over time, but never a mixed set. Hard enough to get a matched set from screaming. Really dunno. Be interesting to see..

 

[Cranky]

I've set up a bunch of rears over time, but never a mixed set. Hard enough to get a matched set from screaming. Really dunno. Be interesting to see..

I've done lots of them too and even had good results setting up used gears in different housings. Had a set of 3.91's that were pitted and talked it over with one of the techs at work after bead blasting them and he said there looked to be enough good metal on them to work ok and they did work fine. I've done a lot of stuff over the years that others said "you're stupid for doing that" and well, they were proved wrong.

 

[68Moparmaniac]

Not recommended

 

[w.Hudson]

A friend broke the spider gears in his Chevelle 12 bolt rear axle and replaced it with a posi-trac and ring gear from another car. I figured that it would end disaster but it was quiet. The rear axle eventually was put in another car that I owned without any problems.

When I was in college, I bought a set of 8 3/4 4.30 ratio gears. They were in a 5 gallon bucket full of water. The gears weren't rusty but had a haze on them and they were discolored. I used a side grinder with a wire wheel and cleaned them up. They were whisper quiet and I ran them a long time. I got lucky.

I have installed a lot of gears over the years. During the 90's you had a 50/50 chance that a new set of gears at the dealer would not make noise. Even today a cheap set of new gears may never be quiet.

Another scenario is that I have had every measurement perfect and they make some type noise. Then throw them together on a sandy beach with a butter knife and a cresent wrench. Never make a sound !!

 

[toolmanmike]

And have them actually run quiet? The thought crossed my pea brain when I pulled a 3.55 pinion out of a chunk that had the diff missing. Probably had a SG and someone pirated it for another gear ratio. The original ring is long gone.....

You'll probably never get them quiet.

 

[toolmanmike]

From a Ford site:

 

[Cranky]

From a Ford site: View attachment 1191172

Heck, if they're noisy, just add some lapping compound to the thing and lap in while driving lol Yeah, I know about how they are made in matched sets but just seeing if anyone else besides me has thought about mixing them.

 

[toolmanmike]

Heck, if they're noisy, just add some lapping compound to the thing and lap in while driving lol Yeah, I know about how they are made in matched sets but just seeing if anyone else besides me has thought about mixing them.

No just you! Actually there were a lot of those discussions on the net. https://www.google.com/search?q=are...30j0i390l4.12034j0j7&sourceid=chrome&ie=UTF-8

 

[Cranky]

No just you! Actually there were a lot of those discussions on the net. https://www.google.com/search?q=are+ring+and+pinion+gears+matched?&rlz=1C1CHBF_enUS901US902&oq=are+ring+and+pinion+gears+matched?&aqs=chrome..69i57j0i22i30j0i390l4.12034j0j7&sourceid=chrome&ie=UTF-8

Saw one where a guy wanted to know if he could mix the ratios! Now that's a bit far out there lol

 

[toolmanmike]

Saw one where a guy wanted to know if he could mix the ratios! Now that's a bit far out there lol

Yep

 

[66Satellite47]

Swapping different gears into a different housing/pumpkin is no big deal, just need a proper setup. Using mismatched ring & pinion sure seems really risky to me.

 

[AR67GTX]

I agree with whoever said it’s hard to get a quiet matched set now - especially if from Richmond.

 

[Dave6T4]

Saw one where a guy wanted to know if he could mix the ratios! Now that's a bit far out there lol

Yeah, great idea! You could use a 3.55 pinion and a 4.10 ring gear to get 3.73's. LOL.

 

[Cranky]

Yeah, great idea! You could use a 3.55 pinion and a 4.10 ring gear to get 3.73's. LOL.

 

[khryslerkid]

I've done a lot of stuff over the years that others said "you're stupid for doing that" and well, they were proved wrong.

I know used sets can be difficult when just replacing bearings, especially pinion. There's always that chance they'll be noisy afterwards.

Mixing a used ring from one set and a used pinion from another is pretty far fetched. That's a lot of work to go through and getting a good pattern might not be that easy. They both were worn differently and what's the chances of them mating up?

90% of the time when you have noisy new gears it's because they weren't set up properly. Different brands get a bad rap for just this.