86 cucv blazer tranny swap

I have a 3 speed auto in my 86 cucv blazer with a 6.2 diesel....looking to swap the tranny out with a 4 speed manual transmission...what will work

Enough time, money and fabricating skills and anything will work.

By the way, this should have been posted in the appropriate forum which is the CUCV mod and hotrodding forum. I'll move it for you, but please post in the right spot later.

sm465. You might gain a couple hundred rpms at road speed with this due to not having torque converter slip. But keep in mind that from a standstill, once you consider the torque amplification of the torque converter, your torque advantage will be close to the same with the THM400 as you would have with the sm465 in creeper gear.

I would say a NV4500 would be a better swap than a SM465. Even a newer one with the 5.61:1 first gear would have more torque multiplication than the TH400s 2.48:1 first coupled through the 2:1 torque converter (estimate).

The best way to do this is with a donor truck because beside the tranny itself your going to find that you need the clutch pedal assy.and clutch assy. shifter,flywheel crossmember,driveshafts ect. Also the starter motor is different from and auto vs standered.
One thing that most don't know is a 6.2 set up for a standard tranny has a small steel tube attached to the valley drain hole in the back of the block. You can do without it just fine BUT if your inj. pump ever starts to leak the fuel will contamate the clutch.
With all that said if I was going to do another one I would look for a 5spd truck to use and stay away from the SM465 that way you'll have an overdrive. I have a 465 in one of my trucks and luckily found an overdrive unit for it from a C-60 dump truck.

My apologies if this is a dumb question...but the transmission is not my area of expertise. Here it is....if one installs the NV4500 does that allow the 6.2 to hold a highway speed on some of those longer, higher hills or allow it to drop down into a better gear to hold say 55 or 60 on those long hills?

I'm not after a 70 mph rig, just one that isn't 45 or worse on those hills. So if a transmission is the answer...then I'm willing to learn!

You won't have the power. I added a turbo and it will run most hills.

Cleptomaniac said:

You won't have the power. I added a turbo and it will run most hills.

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Hmm, I've been thinking over the turbo too. Read through the Diesel Pages vol 1, and keeping an eye open for a Banks unit and also the GM unit that was discussed in another thread here.

So with the stock 3 speed CUCV tranny, how are the RPMs at highway speed...again, I have no plans of blasting ahead at 70+ like most yahoos on the highway. Most of my driving is brief highway and local roads....dreaming of long stretches of forest roads!

Highway speeds are nice and easy with a stock M1009. 60-70mph all day long. At 65mph with stock gears and 30-31" tires you should see about 2200rpm which is right around the upper part of the "sweet spot" for the 6.2L.
Some guys on SS even say they go 75-80mph with their 1009's.

forest522 said:

My apologies if this is a dumb question...but the transmission is not my area of expertise. Here it is....if one installs the NV4500 does that allow the 6.2 to hold a highway speed on some of those longer, higher hills or allow it to drop down into a better gear to hold say 55 or 60 on those long hills?

I'm not after a 70 mph rig, just one that isn't 45 or worse on those hills. So if a transmission is the answer...then I'm willing to learn!

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You'd still have plenty of power and a higher top end, after all the NV4500 is an overdrive tranny, and you don't have to use 5th gear all the time! But is it worth it? Not only the cost but it's going to be a PIA or at least a lot of work. I'm not sure what transfer case you'd use because (I believe but may be wrong) don't most of them have the front drive shaft on the drivers side?
IIRC you've got 308 gears in your truck why not step up just a little in tire size? Just plan it out when you need them and go a little bigger, just make sure you look up a tire rpm calculater so you don't over do it.

nyoffroad said:

IIRC you've got 308 gears in your truck why not step up just a little in tire size? Just plan it out when you need them and go a little bigger, just make sure you look up a tire rpm calculater so you don't over do it.

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To further expand on this: the larger the tire the slower it will be off the line, but the higher the top end speed (and the lower the rpms). Bigger tires will also hurt your hill climbing ability a little bit due to the lower rpms. Small tire= quicker off the line, lower top speed/higher rpms.

@ 65mph with 3.08 gears:
30" tires - 2242rpm
31" " - 2170rpm
33" " - 2038rpm
35" " - 1922rpm