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burnin oil · 11-26-2018, 10:28 PM

I am unsure what trans you have. The old manual I have lists all the transmissions by MM. The only 3 speed trans that I know of called a HD was a Muncie which I never saw hooked to a transfer case.

The only sure fire way to gaurentee what you have for an input gear is to pull it out and have a look. It should be a 10 spline. supposedly all the old manuals had a 10 spline input gear until the round pattern NP205s game out in the 80s. It has been a long time since I looked at a factory 3spd in a 4x4 and I do recall one application using a gear on the outside of the case for the input. I want to say it was a Dana 20 transfercase.

If this was me I wouldnt waste my time swapping any of the 3spd transmissions into your truck. The 465 4spd is a beast and almost impossible to break. it was used in 1/2t up to a C50 or C60 series trucks. All the internals were identical other than the input gear and rear yoke. These are so solid that they are basically give aways at the junk yard and usually found with the trans and tcase still bolted together. Alot of times you can score them both for under $500.

If I was to spend the money it would be the NV4500. The extra gear comes in real nice on the interstate. The only downside is the low granny gear. If you dont need it then you are stuck with a 3sp and OD gear. I personally use the granny gear all the time but I also live on a mountain.

Usually GM was really nice to us and used the adapter plates to adjust the overall lentgh of the drivetrain which allows you to swap the trans and use the same driveshafts as long as the transfer case stayed the same. Cross your fingers on that.

11-26-2018, 10:28 PM	#24
burnin oil Registered User Join Date: Jan 2013 Location: Eastern TN Posts: 1,921	Re: Manual trans question I am unsure what trans you have. The old manual I have lists all the transmissions by MM. The only 3 speed trans that I know of called a HD was a Muncie which I never saw hooked to a transfer case. The only sure fire way to gaurentee what you have for an input gear is to pull it out and have a look. It should be a 10 spline. supposedly all the old manuals had a 10 spline input gear until the round pattern NP205s game out in the 80s. It has been a long time since I looked at a factory 3spd in a 4x4 and I do recall one application using a gear on the outside of the case for the input. I want to say it was a Dana 20 transfercase. If this was me I wouldnt waste my time swapping any of the 3spd transmissions into your truck. The 465 4spd is a beast and almost impossible to break. it was used in 1/2t up to a C50 or C60 series trucks. All the internals were identical other than the input gear and rear yoke. These are so solid that they are basically give aways at the junk yard and usually found with the trans and tcase still bolted together. Alot of times you can score them both for under $500. If I was to spend the money it would be the NV4500. The extra gear comes in real nice on the interstate. The only downside is the low granny gear. If you dont need it then you are stuck with a 3sp and OD gear. I personally use the granny gear all the time but I also live on a mountain. Usually GM was really nice to us and used the adapter plates to adjust the overall lentgh of the drivetrain which allows you to swap the trans and use the same driveshafts as long as the transfer case stayed the same. Cross your fingers on that.