Ring And Pinion With Mismatched Numbers

what will happen if I run a front axle with mismatched ring and pinion numbers?

 

Really not much telling.
They may possibly match up near perfect.
But you should also accept that the service life may be severely compromised.

 

for example are you referring to gear ratio
4:88 front & 5:88 rear
it will run in 2WD only
1"st time in 4WD something is going to explode

 

This is what I understood from the question... but he could mean mismatched axles ...

 

I was thinking he meant say....a 4.88 ring gear and a maybe a 4.27 pinion gear. Not really sure. I would think that even a used pinion from the same gear ratio that is not the one that ran with the original ring gear (4.27 pinion gear from one axle and 4.27 ring gear from another) may eventually have some wear issues. Might get them set up and looking okay but, since they aren't a matched set, they may wear prematurely......if you can get them to pattern well in the first place.

This is pure speculation on my part. I am not gear head and I did not sleep at a Holiday Inn Express last night.

 

Both gear ratio's are 5.88. The R&P are not a matched set. When I opened the differential
the wear pattern actually looked good. I will try to post a photo.

 

Front axle , run it dont worry.

 

This would be my thinking too. Duty cycle is so low on the front axle, you'll get away with it.

 

5.88? or 5.38?

 

Sorry, 5.38

 

Yeah that's what I think.
Run it as is.
So long as the ratios are identical its mostly O.K.
Mismatched R+P may not be ideal but it really depends on how well the gear tooth face angles mesh up.
Prussian blue will reveal the true fit.
Heck I've seen supposedly matched R+P that did not match very well according to the prussian blue.
It will get noisy if its not happy.

 

Just don't run it on dry asphalt.

 

I will install and check contact pattern.

 

If they are already installed and no issues I would probably continue to run them. I would never intentionally install mismatched ring and pinion gears as it is a lot of work and too much to go wrong by rolling the dice on it.

 

The gears were used in a complete axle that I bought. I don't know the history but the teeth on both R&P looked good but there was some slack somewhere (maybe in the spider gears) but the backlash on the ring gear felt like it was in spec. I did not find out about the mismatched R&P until I tore it down to clean it up and check the bearings. I just set the pinion bearing preload and will try to check the gear mesh pattern tomorrow.

 

Just as a bit of information. Ring and Pinions are not made as a set. They are made to a tolerance in large batches. They are matched so to speak by checking to a known standard and then marked and matched together buy the fit based on the tolerances. Any 2 gears could in theory be used so long as the wear is not excessive, front axles don't get used much so there easier than a set for the rear drive gears.

 

Here are photos of the contact pattern. The ring gear backlash is .003.
What do you think?
Thanks

 

True, they are not manufactured as a set, but they are lapped together on machinery. that's why it's important to make sure the numbers match and why they number match them to begin with.