Solid 5 speed truck trans behind a 454

[J. Gatz]

Hey guys, i have a 79 k10 that im doing a frame off restoration on. It came with a 350 and an abused 4speed. Iv pulled those an Im going to fix her up right and id like to put a big block in with a solid 5 speed behind it. I have no intentions of being hard on this truck. No wheeling, no racing, no pulling. Just a stout rig that's dependable. Any suggestions on a quality 5speed truck trans?

Thanks!!

[LockDoc]

Originally Posted by J. Gatz

Hey guys, i have a 79 k10 that im doing a frame off restoration on. It came with a 350 and an abused 4speed. Iv pulled those an Im going to fix her up right and id like to put a big block in with a solid 5 speed behind it. I have no intentions of being hard on this truck. No wheeling, no racing, no pulling. Just a stout rig that's dependable. Any suggestions on a quality 5speed truck trans?

Thanks!!

GM NV4500, Richmond, or Tremec 5 speed overdrive.

LockDoc

[jocko]

Agreed. T5 comes up in this discussion often, but it's more for a small-block hot rod or a 6, I wouldn't put it behind a big block.

[74CustomK20]

Nv4500 with the fixes

[Tom]

Originally Posted by jocko

Agreed. T5 comes up in this discussion often, but it's more for a small-block hot rod or a 6, I wouldn't put it behind a big block.

Most people won't put it behind a small block either, certainly not a hot rodded small block.

NV4500 is what the OP wants. OEM 5sp with a big block.

[Big Port Jimmy 6]

Clark VO, he said he wanted a truck trans.

[andrewmp6]

Being he has a 4x4 the nv4500 is his only option really unless he wants to run a divorced t case.

[mongocanfly]

Ditto ditto ditto....nv4500

[hatzie]

Originally Posted by andrewmp6

Being he has a 4x4 the nv4500 is his only option really unless he wants to run a divorced t case.

Yup. For five speeds in a K series with a big block the NV4500 is pretty much it.
A Ranger OD gear splitter or Gear Vendors overdrive unit on the SM465 are other options. You actually get 8 forward gears with this setup but there's likely overlap.
The price of all three of the above end up being pretty much the same.

The NV3500 is a five speed, and can be had in 4x4 dress, but the torque capacity peaks at 290-300ft-lb... not enough for a Big Block 400 say nothing of a 454.

The S10 4x4 T5, rated at only 250ft-lb, doesn't have anywhere near the torque capacity for a mildly built smallblock, stock 6.2L Diesel, or even a 250 I6.

The NP440/A833 MM7 doesn't quite have the torque capacity for a 454 and, even tho it's an overdrive trans, it's a 4 speed.

[andrewmp6]

Only thing i can think of is what t case will work on that nv4500.The newer trucks have a driver side drop and he needs a passenger side drop.

[dragn91]

They make adapters to run all sorts of t cases behind the nv4500 but a round pattern 205 works with a cheap spacer. I got lucky and found my 205 and trans mount out of a 1988 squarebody one ton truck for $80 look for people parting out late model squarebodys with th 400 transmissions. Advanced adapters sells everything you need. I think a round pattern 208 or 241? Out of squarebodys would work as well but not as strong and you have to match the spline count on whitchever one you use to the trans. I think its 32 im sure someone will correct me if im wrong. Im putting this swap together now in my k30 behind a 6.2

[hatzie]

32 spline GM LH drop NP241 and GM LH Drop NP208C are bolt up and go. These both have deep 2.72:1 low range and are fairly light weight. The NP208C is usually pretty cheap. I wouldn't hesitate to use either one. Despite comments to the contrary the NP241 & NP208 will put up with a fair amount of abuse before they let go. I beat heck out an NP208 plowing. It was mounted behind a 460 & C6 in a 1986 F250. The C6 transmission, the Dana 44 TTB front axle, and Dana 70 rear axles blew up along with one front propshaft but that transfer case held up for 6 years of harsh abuse. I did keep it full of the proper fluid and changed it out in the spring and fall.

NP205 will fit with adapters and modifications. The NP205 is fairly expensive, only has a shallow 1.96:1 Low range, is heavier than a dead horse, and some adapters require that you cut down the NV4500 mainshaft.

Whatever you do... Install a torque brace from the transfer case to the bellhousing unless you like snapping off transfer case adapters or transmission tails.

The later 1980's SM465 & all the TH400/3L80, and 4L80 transmissions have 32 spline output shafts. The TH350, TH700R4, & 4L60 are 27 spline outputs. The 80's GM CUCV M1008, M1009, etc are good donors.

[andrewmp6]

Unless he wants a hardcore off roader a np205 is kinda overkill and pricey.Since the np208 will fit they are cheap easy to find and like said not as weak as people say.

[hatzie]

The main problem with the NP208/241 is the shifter is mounted to the floor not the transmission/transfer case. If the body mounts are loose the shifter can move some in relation to the driveline. That movement over time fouls the nylon wear buttons on the shifting fork just like resting your hand on the shifter knob.

There are several cable shifter kits. Novak and JB Custom Fabrication come to mind.
Novak makes a transmission/transfer case side mounted shifter for the 231, 241, & 242 that should work fine on the NP208.

You may be able to repurpose a console shifter by cutting out a custom gate plate.

[J. Gatz]

Thanks so much for tour help guys! Happy to be a new member of this community!

[tucsonjwt]

I have a SM465 and gear vendor in my 83 C20 454. You really can't get 8 gears with a gear vendor. The first granny low 1 gear is never used. You cannot engage the gear vendor until about 30 mph or the engine will lug. So, I engage the gear vendor between 3rd and 4th gear, so I only really have a 5 speed. I have a 4:10 rear, so with a granny 4 spd you don't get up to speed until 3rd gear.

[andrewmp6]

Originally Posted by J. Gatz

Thanks so much for tour help guys! Happy to be a new member of this community!

Welcome to the forum,We have a lot of people that know a ton about these trucks.We even have one member that use to assembly line when these trucks was new.When you get the chance start a build threat on here with your truck we always love to see more of them.And if you need anymore help with anything don't be scared to ask.