Is there any disadvantage to swapping the original GU5, 3 carrier LS1 rear end with a GU2, 2 carrier LS1 rear end? My current rear end might need replaced and I'm looking for a used one to replace it with. I plan on putting 3.73's in either rear end that I get installed. Also, my car does not have TCS, but will a 4 channel rear end still work with no modifications?

 

3= 3 series gears, 2= 2 series gears as far as i know. 3.42 3.73 ect.

 

No, the 4 channel rear end needs some modification. Check the FAQs at the head of the section. Also a 2 series carrier won't accept OEM 3.73 gears, they're made for 3 series carriers. Just get a 3 channel factory rear and save yourself a lot of time and headaches.

 

I think I'll find a 3 channel rear end, but most of what I've seen are series 2 carriers. Any disadvantage to choosing the 2 carrier over the 3 carrier? So I can upgrade a 2 series carrier to 3.73's as long as their aftermarket gears? That's all I care about. I don't want to switch to a series 2 carrier and then be stuck with nothing higher than a 3.08 gearing.

 

The 2 series carriers were used for factory 2.73 or 3.08 gears. The 3 series were used for 3.23 & 3.42 gears.
You can put an aftermarket gear set (called thick gears) in a 2 series carrier. I have run a 3.42 in mine for years.
AFAIK, there is no disadvantage to running a 2 series carrier, other than you have to use aftermarket gears. I run Strange; Motive and Richmond also make them, and others might as well.

 

Does Summit make a series 2 carrier compatible 3.73?

 

Yes, they carry Richmond and Strange. Not their house brand, which they don't actually make anyway.

 

Does it make a difference if the rear end I get comes from an automatic or manual? I'm having a hell of a time finding 3 channel, 3 series rear end even on Ebay. They all have TCS and I don't want to have to do that mod.