Correct NP205 front output for '84 blazer

[Big _Betsy_Red]

I purchased a very nicely rebuild transfer case from ***** transmission company. Everything looks great except for the front output. They sold me a 1.125" diameter 10 spline front output. The invoice says 78 - 84 10SPLinput but no mention of the output shafts.

My quick youtube wikipedia research tells me that the correct front output is 30 spline for the '84 NP 205 (advanced adapters told me so here https://www.advanceadapters .com/1-gm-new-process-205). The one on the T-case I removed is 30 spline 1.375" diameter.

My front drive shaft has 601-x and *some illegible character 44 on the front centering yoke of the double cardan. Photos are attached.

Any info would be great!

 

[nvrenuf]

It should be 30 spline as the 10 to 30 spline change coincided with the yoke to flange change in the late 70’s.

That said, if you’re going to spend money and replace it I’d highly recommend going to a 32 spline shaft (found in Ford / Dodge 205’s). The 32 is stronger and the yoke / flange selection is far greater. It’s been a while, the seal is different but I’m not sure if the seal retainer is the same or needs to be changed as well.

 

[Big _Betsy_Red]

Might as well just go with a ford 9" rear and be done with it HAHA!

I wonder how much room there is with the bigger CV over the cross member. Might have to shorten her a bit if I'm going to go with something bigger. Maybe spacers between the frame/cross member and cross member/transmission instead of shortening the cross member section. Interesting.

 

[nvrenuf]

Don’t put spacers between the frame and crossmember, doing this will improve the rear angle but make the front worse.

 

[Big _Betsy_Red]

Anymore spacers* FTFY Just another good reason to leave the stock 30 spline. What is 30 spline good up to 40" tires and 800 #-ft? Doubt Ill change it but that does sound cool!

 

[nvrenuf]

Anymore spacers* FTFY Just another good reason to leave the stock 30 spline. What is 30 spline good up to 40" tires and 800 #-ft? Doubt Ill change it but that does sound cool!

I don’t understand, you said you had 10 spline. My point was that if you’re going to change the shaft why not point the best in? You’ll probably spend 3/4 of the cost.

 

[Big _Betsy_Red]

In your opinion it is "the best". If my plan was to put 45"+ tires on her down the road it would probably be my opinion too.

 

[Big _Betsy_Red]

You are right though. I am going to probably put the 32 spline in the old case and rebuild it. Thanks for the suggestion!