When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am currently in the process of getting my car on the road. I finally got it running decent and everything and went to take it on first drive and the rear end was making terrible noises (Didn't check rear end before taking for spin, my fault) I took it about 2 houses down and came back.. lifted the rear end, pulled the cover, let the fluid drain and inspected.
At first glance nothing looked bad, I turned the driveshaft over and saw what was going on.. two of the teeth were missing on the ring gear (pinion gear looks ok) they were stuck to the magnet on the diff cover. but it appears everything else is... ok
now to my real question. if I order a ring/pinion set and install kit for my axle.. is there anything I should be concerned with it having 26 spline axels vs 28 and being (more than likely) an 7.5 vs a 7.625 rear end.. I just don't want to buy the everything and run into any issues. my brother is a certified mechanic and has all the tools to do the swap for me.. but I just want to be sure what I am doing before I order parts.
the kits I am finding don't specify axels.. and if they do.. they generally say 28.. but most kits say the gears are good for 7.5/7.625 rear ends.. so I am probably safe there.. just want to confirm.
Gears have nothing to do with axel spline. The splines mate with the differential carrier which holds the ring gear. As long as the gears match the differential diameter (7.5 or 7.625) that you have, you can use them. That is why the axel spline count is not specified for gear sets. HTH
The after market gears are 7.6 and will fit your 7.5 with no problems. You didn't say what the gear ratio is. Just be sure that you get the correct gears for the series of differential that you have. Check the FAQ about 10 bolts sticky for more information on your rear end.
There are good installation kits and bad installation kits. Some of the good ones are Tom's Differentials, Yukon and USA Standard, in that order. Some of the worst are Ratech and Richmond.
Just be sure that your brother knows how to set the pinion depth, bearing preload and backlash, and knows how to read the contact pattern before you get into this. I've seen many certified mechanics that didn't have a clue about how to correctly set up a set of gears. They just used the shims that were already in there and hammered everything in. Then they couldn't figure out why the customers kept coming back complaining about noise from the rear end.
ok cool.. yea my rear end is either a 3.42 or 3.73 which should be a series 3 carrier regardless correct? yea I heard some bad things about the Ratech kit.
Not too concerned with the assembly part.. hes pretty knowledgeable on this stuff, been a certified master mechanic for a long time, and has done a lot of rear end work on his own personal vehicles that I know first hand have had no issues.
ok here are a few pics of the inside of my differential.. it appears to be a gov-lock posi unit (I know these are kinda junky, but not a huge concern at the moment. really just concerned about getting the car on the road.. the stamping on the ring/pinion is "11 41" which makes it 3.73 (RPO GT4).
now I have some people telling me it would be cheaper/easier to just find another rear end and swap in, but was wondering if it makes sense to do that or just do the gear swap? I won't know the condition of another rear without ripping it open as well.. so I am a little hesitant to buy one used.. and buying new/rebuilt is out of the question at the moment. I may have found a set of new 3.73 GM stock gears for $50 (a buddy's shop had a set), and if that is the case with an install kit should put me around $200 or so for this..
what are everyone's thoughts on swapping gears vs just replacing the whole rear end (side note I would like to keep the rear end 3rd gen so I can keep running the stock wheels, and they are harder to come by for me than the 4th gen rears)
I would say that the 3.73 rear ends are probably hard to find. If you have a new set of GM 3.73 gears then that's a big plus. They will set up better and run quieter than after market gears. New GM gears are well over $300 a set. Just get a GOOD installation kit. Tom's Differentials and Yukon would be my first and second choice. USA standard would be distant third.
04-27-2015, 11:29 AM
