Doubler length question

[orangeGMC]

I read on your website that the Gen 2 doubler is the same overall length as an original NP203. Is this correct? Does that mean that I can use my original driveshafts? I have an operating 203 in right now. If so I will be purchasing a kit real soon.

 

[miniwally]

This will depend on the configuration of your rear driveshaft currently. It also depends on what the configuration of doubler output you get.

Most if not all of the doublers will have a flange to mount a CV joint or a yoke to mount the ujoint in.

If your 203 has either of these you should be okay. If you have a slip yoke 203 you will need to do something with your rear driveshaft.

The best bet is to just call up and talk to Stephen. This is the busy time of year and Easter Jeep Safari is only a few weeks away so he doesn't get on here to much to check in.

 

[Hossbaby50]

I helped install a Gen II doubler in a friends truck that was a TH350/203 truck. They are not exactly the same but they are close enough for the rear driveshaft to work. The front is another story. The front did not work. It was to short by a couple inches and with the 2" clocking on the 205 it was at WAY to much angle for a stock CV front driveshaft. The CV was bound up with the truck just sitting in the driveway.

This problem can be solved if you grind the piss out of the stock CV stops off but that will make the driveshaft unbalanced and put the CV at higher risk to blow up under hard use. Then you are still left with the shaft being to short. You can either lengthen it yourself or the other option that cures both the CV problem and the length problem is a new heavy duty CV driveshaft made to order.

Harley

 

[az-k5]

You will have to lower the t-case about an inch (at least in a K5) to keep it from a massive driveline vibe. Even then it will groan on you when you let off of the gas. My front CV is a crappy saginaw (tiny) version, that I have ground the piss out of (ever seen one hit the 30°+ range) it pops and clanks but since the ball-socket is wasted but hasn't blown (even though I have tried to kill it). Also I onlt have a 4" lift and a TH350.

 

[Stephen]

If you have a 350/203 combo, your rear driveshaft will work. Any length difference is due to case length variations, yoke variations, etc, the overall lengths are very close to the same. The front driveshaft will have to be different, it'll come up about 3" short.

Watch the rotation, it's easy to get excited about more ground clearance and have to order an expensive front driveshaft to work with it. The 350 trans is the shortest GM built so the angles can get steep. Typically we recommend the 2" up rotation with a 4-6" lift and not over 6" at all. At 6", you may have some problems with the short trans.

 

[orangeGMC]

What if I didn't clock up the 205? Would that be better? My plans include an 8" lift later on in life and I want to get the drivetrain done first.

 

[Hossbaby50]

If you don't clock the 205 it hangs down a bit. I would recommend that you clock the case up and then just cut and lengthen you front driveshaft yourself and grind the CV stops out so it will have enough angularity. Then once the drivetrain is done get HAD or whoever to make you the correct driveshaft.

The downside to cutting up your driveshaft and grinding the CV is that it won't be balanced anymore so doing hispeed stuff may be limited till you get a new driveshaft.

Harley

 

[Stephen]

with an 8" lift and a TH350 trans, I'd have to recommend against the up rotation, unless you're really tuned into the problems you're going to have to solve. In this case, if it's really important to have that belly clearance, I'd say you should start doing some serious geometry to find out just what kind of angles you're going to be running. I'm not saying it's impossible, I just don't want you to end up needing more front driveshaft than you want to afford. You can do some measuring off of what you have already, just plan on the front output going up about 2" and back 3" compared to the 350/203 combo.