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Hello everyone I'm looking to swap my gears to 3.73. From what I have gathered and did the spin test I have a 10 bolt 8.5 posi unit with 2.56 gears currenty. I have a LS 5.3 swap with 4L60E trany. My question. I want to buy Richmond Gears 3.73 part # 49-0041-1 will these work with my Carrier or do I need other parts. Or is there another manufacturer that makes 3.73 that work with my current carrier which I don't know what it is..Thank you guys
Yes. In theory you could also use a ring gear spacer on your existing carrier, but that would not be as strong as using the "correct" series carrier with the ring gear.
The US Gear web site doesn't show anything about which carrier they will fit, so my guess would be they are similar to factory gears. This may be why their info shows the carrier breaks below: 2.56 and lower is a 2 series carrier and 2.73 and up is a 3 series carrier. That would mean for their 3.73 gears you would need a 3 series carrier.
Someone out there may make 3.73 gears that fit a 2 series carrier but I don't know about them. I would say check with monzaz as he does this stuff for a living.
The US Gear web site doesn't show anything about which carrier they will fit, so my guess would be they are similar to factory gears. This may be why their info shows the carrier breaks below: 2.56 and lower is a 2 series carrier and 2.73 and up is a 3 series carrier. That would mean for their 3.73 gears you would need a 3 series carrier.
Someone out there may make 3.73 gears that fit a 2 series carrier but I don't know about them. I would say check with monzaz as he does this stuff for a living.
Ok let me shoot him a message I hear his name mentioned alot in the gear forums...thank you for the help I just want to make sure I purchase the correct stuff and save my self a headache or 2.
There are NO thick 8.5 gears like as in the 7.5. GM aftermarket or other wise.
2.73 - 5.57 are all 3 series gears
2.41 - 2.56 are all 2 series gears
there is a 2.24 also we found in a caddilac seville 47 ring and 21 pinion 2.2380952 totally amazed to find this ratio... sold them to the flats guys...
If you are hanging on the street and very little track under 12 sec mark you should be ok with a ring gear spacer Kit ... proper length bolts is the key as this is what makes a ring gear spacer fail. If your spacing .200 more the bolts need to be that much longer too.
We did a test on a 12 bolt Chevy early in the companies beginning to knock all the crazy taboo info about these things in the differential world.
Ring gear spacer was the first one.
We too a 2 series 12 bolt Chevy POSI installed a spacer and 4.10 THICK gears for a 3 series carrier. Installed all that and ran it at the track for years ...on the street burn outs 454 motor beat on it pretty good 4-5 years I think proved that incorrect info. 12.10 with slicks 2500 stall 29" x 9 slicks.
If you are going faster than 12 sec you have invested enough money to make a steel full bodied car you should now invest in correct parts to continue going faster etc.
Installation details really does go far in most application and reason why parts usually fail if NOT defective from the get go.
I am sure SOMEONE will chime in and give guff... this is just our experience with them. You can take or leave this info.
We do understand it can save you money on a complete new posi carrier. Just do not be too cheap if you really can afford to buy better safer parts.
Just trying to give real world info with out bias attitude as much as possible.
There are NO thick 8.5 gears like as in the 7.5. GM aftermarket or other wise.
2.73 - 5.57 are all 3 series gears
2.41 - 2.56 are all 2 series gears
there is a 2.24 also we found in a caddilac seville 47 ring and 21 pinion 2.2380952 totally amazed to find this ratio... sold them to the flats guys...
If you are hanging on the street and very little track under 12 sec mark you should be ok with a ring gear spacer Kit ... proper length bolts is the key as this is what makes a ring gear spacer fail. If your spacing .200 more the bolts need to be that much longer too.
We did a test on a 12 bolt Chevy early in the companies beginning to knock all the crazy taboo info about these things in the differential world.
Ring gear spacer was the first one.
We too a 2 series 12 bolt Chevy POSI installed a spacer and 4.10 THICK gears for a 3 series carrier. Installed all that and ran it at the track for years ...on the street burn outs 454 motor beat on it pretty good 4-5 years I think proved that incorrect info. 12.10 with slicks 2500 stall 29" x 9 slicks.
If you are going faster than 12 sec you have invested enough money to make a steel full bodied car you should now invest in correct parts to continue going faster etc.
Installation details really does go far in most application and reason why parts usually fail if NOT defective from the get go.
I am sure SOMEONE will chime in and give guff... this is just our experience with them. You can take or leave this info.
We do understand it can save you money on a complete new posi carrier. Just do not be too cheap if you really can afford to buy better safer parts.
Just trying to give real world info with out bias attitude as much as possible.
Jim
JD
Thank you sir I will take this info and just have a shop do it..lol..definitely not under 12 car and will not see a track. Thank you guys for the info.
CArrier?
That is the casting number of the housing? Y/N?
It will not tell you which carrier you have? 2 or 3 series posi or non posi etc.
or
Am I missing something?
we IDed the rear as a 8.5 GM
Yes sorry that's the housing #..Both tires turned the same direction so I'm sure that's POSI but I could not calculate my gear ratio I came up with 3 or so..I do know my RPM stay pretty Low on the hiway.
