I would like to upgrade my driveshaft to a 1350 yoke unit. I'm currently running a built 4L60E and a stock 10 bolt rear. The trans was built with me having a stock DS, so U-Joint was not upgraded there.

Is there a way that I can upgrade the joint on the trans itself, and then run an adapter for the rear (I plan on upgrading the rear after it blows up)? I know there is an adapter to run the stock DS with an upgraded joint on an upgraded rear, but was not sure if they made an adapter for the other way around, nor what I should do on the trans.

 

I think most people would consider the front universal joint as part of the driveshaft. The slipyoke is the interface between the driveshaft assembly and the trans. The universal joint is between the slipyoke and the shaft itself and is usaully not disassembled. Some vehicles use a fixed output on the trans, but ours is a slipyoke.

Yes you could run the stock 3R slipyoke-> a conversion ujoint-> 1350 ended shaft and then convert back at the other end using the same conversion ujoint in opposite.
OR You could upgrade your slipyoke with the new driveshaft to a full a 1350 up front and a 1350 x saginaw 3R u joint in the rear(I don't have the exact PNs for that handy). Then when you upgrade rears switch just the universal in the driveshaft to a 1350x1350.

I wouldn't recommend doing this for 2 reasons though.
1. depending on what rear you upgrade to you may need a custom length shaft
2. the stock ujoints aren't the weak link, usually the 10 bolt blows before them so whats your motivation to upgrade your driveshaft?


FYI here are the four most common fbody ujoint types:

1310 Spicer Series: 1 1/16" Cup Diameter 3 7/32" length

1330 Spicer Series: 1 1/16" Cup Diameter 3 5/8" length

3R Saginaw Series: 1 1/8" Cup Diameter Retained with internal clip 2 5/8" Length. Most common GM joint.

1350 Spicer Series: 1 3/16" Cup Diameter 3 5/8" length

Stock is all 3R the full way through.
If you have a 1LE driveshaft is is a 1310x1310 up front between the slipyoke and main shaft, then uses a 1310 x 3r conversion joint at the rear for the 10 bolt. There are conversion joints available through most autoparts stores to go between any of the 4.

-Brent

 

So you think I should wait until I get a new rear before upgrading the shaft because the length may change depending on the rear I go with?

I want to upgrade now because I have the crappy stock LT1 shaft which I'm sure is causing a lot of vibration, and the anti-shock characteristics of a CF shaft should help the longevity of both the trans and the rear (at least in theory).

 

I understand a lot of LT1 owners go with an LS1 ds with no problems and it seems to solve the vibration issues. They're also cheap and easy to get a hold of.

 

Thats correct, don't spend big bucks on a driveshaft till you have your final configuration length nailed down.

The LS1 suggestion isn't bad because they are pretty cheap.

You could also try rotating your stock steel shaft 180degrees at the rear ujoint. Also try different meshes in the front between the tranny and the slipyoke. This of course is FREE to try.

Or you could get your stock shaft rebalanced for a minimal cost.

Before you buy a carbon fibre shaft, search on here. Injuneer has some comments on the different suppliers, which ones work and which dont. Not very many people at all run them.

A lot of people make broad assumptions about a part based on only the material. Because carbon fibers stiffness is directional and it depends on how it is laid up (the weave directions if you will). Youngs modulus for aluminum<steel<carbon fiber. However, thickness of the part, density of the material, and in carbon fiber's case directionality all play in and the geometric design features could result in the stiffest part being made our of any of the 3. The point i'm trying to make is that you need to know a LOT more about a part before you determine its effective stiffness, strength, or weight. For a driveshaft you definitly need wall thickness, tubesize, and with carbon fiber information on how the individual strands were laid directionally before you determine if it is stiffer or more supple then an aluminum or steel shaft.

-Brent