Ok, you wanted info, here it is:!!! This is right from a previous Doubler post, so it goes over some stuff that's redundant, but cut and paste is easy!
Ok, the GEN2 requires a 32 spline female input gear. You have to use the "short" version input gear. We've found 2 32 spline female input gears, one sticks out of the case about 1 1/4", the other sticks out of the case about 3 1/2". For the GEN2 you have to have the short stickout. Luckily, the short gear is the most common, the long one appeared mostly in later 205's (86ish and up) with the round bolt pattern.
As for the case pattern, we can do either the round pattern, or the Fig 8 pattern, no problems either way. Or you can put a Ford 205 on it, or even an Atlas.
Now, if you don't have a 32 spline input gear.....2 options, one is to modify your case to the 32 spl., the other is to wait. More on waiting later. (get it, wait on waiting...ok, back to work) There are 2 basic cases available in the NP205, (we're not going to talk about the round pattern here since they were all "big input") One has the "small input" the other is the "big input". This refers to the size of the input gear bearing itself. The 27 and 10 spline (TH350 and SM465 versions) use the "small input", the TH400 uses the "big input". The difference in the hole in the case is over .300". To modify a case with the "small input" you just cut (mill usually) the hole to the bigger size. Then you can install the 32 spline input gear and you're ready to go for the GEN2 Doubler. We also have a 205 case exchange going on here where we send you an empty 205 case with the input hole already bored out, and you send us your empty 205 case back as a core. The cost for the service is $100, and the core charge is $200.
Now, on the 10 spline, in factory applications, the 10 spline connection tends to wear out somewhere around 80-100K miles, depending on usage. The drivesleeve (female splined coupler) is soft enough that it wears out and creates a good deal of backlash in the system. If it wears enough to strip out, you stand a chance of ruining one or both of the shafts. We're researching what it would take to build a system that won't wear out. A big factor we're keeping in mind is that most of the trucks with Doublers in them are or become vehicles that don't see many miles. The miles they do get are pretty rough, but overall, the numbers aren't really high. So, some wear may be acceptable.
For max durability, the 32 spline is the way to go. It's fine enough that wear isn't an issue and strong enough that you'll rip outputs out of the 205 before you break an input. In the real world, you'll either spin the tires, or break a ujoint, axleshaft, or other driveline part.
I think this answers the questions, whew!
Ok, price for the case exchange is up in the text, cost for the new input gear ($140) and bearing ($30) is $170, and if you want, we have rebuild kits for the 205 that are about $190, and include all the overhaul parts, including the big bearing for the TH400 gear. So buying the rebuild kit saves you buying the bearing for the gear.
Hope this helps get it all straight.
Making the world better, one truck at a time.
SW-ORD
