NV4500/241 question

[SunSoaked]

Will I need an adapter to mate a 241 to a NV4500 or does the 4wd version NV4500 incorporate the correct bolt pattern?

Im thinking about buying a 241 and swapping input shafts (32 spl), but not sure on the mounting since the 27 spl shafts came from a 350/700 trans.

Thanks

[DirtyLarry]

You need to just get a 4x4 version of a NV4500 and a TH400/SM465 NP241 and you’ll be all set. A 2wd NV4500 has a completely different output shaft that will be very costly to convert to 4x4 aside from the cost to purchase the correct rear adapter.

Here is a 4x4 NV4500 with the SAE round adapter that fits all GM tcases with round SAE round flanges. (Actually Ferd and Chysler also use this same SAE round flange for their tcase to transmissions) The only difference between certain transmissions is spline count as you are already aware. NV4500/TH400/ later SM465s have 32 splines. TH350/700R7 have 27 splines.

[SunSoaked]

I guess what I need is some verification regarding this ad I'm considering. I plan on putting this behind a 4wd version NV4500. I know I'll need a 32 spline input, but I'm ok with that. Does anything not look right here? I thought the rear output is always 32 and the front is 27?

NP241 manual shift t-case
2.72 ratio
6 bolt round
27 spline rear output

Out of an early 90s truck. Includes linkage and shifter

[DirtyLarry]

No, the rear tcase output (driveshaft yoke end) may be a different spline count than the tcase input (transmission side). To be honest, I’ve never paid any attention to tcase output spline counts because I usually don’t run slip yoke type drive shafts. That said, the bigger issue with the pictures you just posted is that tcase is for a GMT400 truck with IFS where it has a left output for the front drive shaft. That isn’t compatible with old GM trucks unless you plan on swapping in a Ford type front axle with a left side pig. Need to go back and surf more CL or visit a boneyard and look for a 1987 -1991 square body style truck with a TH400 or SM465 manual to grab the tcase from. Who knows, maybe you’ll even find a SAE round pattern 32 spine 205 somewhere along the line. 241s are great but 205’s are better although on my Suburban NV4500 swap, I will be using a 241 because it already has a 32 spline 241 in it already. Good luck my friend. We’ll help you get this figured out yet!

[SunSoaked]

Thanks Larry-

I almost jumped on this. I didn't realize it was for the newer trucks.

I more I know, the more I realize how much I dont know

Mike

[JPalmer81]

I think the 1 ton trucks from 1987-1991 had the round pattern np205 32 spline, they may have put them on some earlier 1 tons too, not for sure though. Good luck.

[obijuan]

for what its worth, the round pattern gm 205 came about in 1985 k30 models and went to 1991. 1990 and 1991 had VSS speedometers. from then on regular cabs then had slip yokes and the crew cabs had fixed yokes.

this enabled Gm to use the same crossmembers and mounts for 1/2,3/4, and 1 tons. previously there was a one ton specific crossmember.
the half tons had a 6" frame rail and the crossmember sat underneath, the one tons had an 8" rail and the crossmember is inside the rails.

[SunSoaked]

What I dont get is the M1009 (87 1 ton) chasis I pulled the axles from had an aluminum t case in it. I sent it to the boneyard with the extra parts I didn't need. I figured (incorrectly) my 69 had a 205 in it. Turned out to be a T221. Back to the 1009, I assumed because it was aluminum, it was not a 205. Now I'm wondering what it was? But its long gone at this point.

[obijuan]

The cucv only came with 208s. Only the m1028a2 I think had the 205 because of the PUTO for the utility body or ambulance thing.
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