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So...theoretical SM465 swap into a 6.2L/TH400 equipped truck

AJMBLAZER

AJMBLAZER

Better to be lucky than good.
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I like Big Ugly but I'm a stick guy. LOVED my Ranger because of that 5 speed stick it had. It wasn't low geared in 1st but you could still put it in the gear you wanted and not what the transmission finally decided on.

So somewhere in the distant future is a stick transmission for Big Ugly. This is after we sell our house, move south, and have a place where I can stash this thing and do the work. Just asking now because I've always wondered, I know several of you have done this swap, and there's a SM465/NP205 combo in the local CL for stupid cheap (but I don't have the space, time, or money to blow on it unfortunately:crazy:).

Ideal would be to find a long bed 3/4 or 1 ton 4x4 with a 6.2L and a SM465 already but yeah...good luck.

So what's different between a 6.2L manual truck of this era and a SBC or BBC with a manual?

What transfer case would they have? 208 in a 3/4 ton and 205 in a 1 ton? I'm cool with either really.

If I ran across a gasser truck with all the doodads what parts would I need to make it work in Big Ugly?

What's the difference in driveshafts between a SM465 equipped truck and a TH400 equipped truck?

Any particular vintages or combos to look for and/or avoid?

Thoughts, comments, concerns? Educate the noob please.
 
I'm still figuring out my 700r4 to nv4500 swap, but the general gist is a diesel flywheel, clutch, pressure plate master slave etc, clutch pedal and linkage. Bell housing pattern is the same as a sbc or bbc from the same era, may need slightly more clearance for the diesel starter (At least the nv4500 needs more clearance with a gas bellhousing.). I'm still a few months from making the magic happen on my build, so can't help with the driveshaft measurements (mines getting a doubler anyway and its a blazer). Hope my bable helps....Dave
 
Well, I'd love a NV4500 but I think for my skill level and especially money level a SM465 would do the trick. Also that would mean everything needed for the swap would be an existing, meant for a 73-87 GM truck, part.
 
It will be much easier doing the sm465, I just wanted OD and a stick. I think I'm up to parts from 10 different models of truck on my build now. It gets confusing lol...Dave
 
Yeah. I read tRUSTy's NV4500 swap thread a while back...oy...too much drama, custom or one off part drama, and expense for me. He got it done and built right...but I'm not up to that stuff.

One day...maybe...SM465 - Ranger OD gearbox - t-case.
 
I replaced a 700r4 / NP208 combo in my old 86 6.2L powered truck with an NV3500 / NP241 combo, and it was nearly a bolt in swap. I used the factory internal slave cylinder and had to fabricate a mount for the newer clutch master, and also had to deal with shifter boot to transfercase shifter clearance issues.

Starting around 81 or 82, all transmission / transfercase combos were made to be about the same length. If you switch your TH400 out with an SM465 or NV4500, you should be able to bolt your original transfercase straight up to the new transmission, and re-use your original driveshafts. You shouldn't even have to move your transmission mount.

The SM465 is certainly a far easier transmission to install based on the fact that parts are far more common, and that those transmissions were available in these trucks from the factory with a 6.2L diesel, but the O/D gear offered by the NV4500 is a really nice thing to have, esspecially if you have 4.56 gears in your M1008

Personally, I'd never run anything but a manual transmission behind a 6.2L diesel. Having run an automatic, SM465, NV4500 and NV3500, I wound back up with the NV3500 for it's excellent gear spacing, and use of all 5 gears during normal driving. The NV4500 drove just like an SM465 with an extra gear. Lost all my boost between each shift as I'd go from racing the engine to bogging it with the 1st 3 gears.
 
This is all theoretical mind you...


...the "off the shelf" drivetrain combo of the SM465 is what appeals to me. As in I find a complete truck to swap parts from for cheap and whalla, everything (or the majority of it) that I need is right there.
Now later on (or if this whole thing takes years to come to fruition and I'm a better mechanic and have more money) then yeah, I could see doing a NV4500 swap first. OD would be nice but I'm not that worried about it. I don't do freeway cruises with it and it does 55-60 mph pretty happily right now thanks to the 38's. Don't plan on going down in tire size.
Then again there's the Ranger box that MaxPF was talking about last year...
 
Ah, didn't notice that you have redneck overdrive already :D

In that case, your O/D gear wouldn't be very useful on the highway anyways. An SM465 is nearly a bolt in deal man! Gotta cut a hole in the floor for the shifter, a hole on the firewall for the hydraulic master. The rest is bolt in kind of stuff :)
 
Yeah, the 38's make a big difference. I lost a bit of gas mileage but it's not roaring at speed anymore. It'll actually do freeway speeds but it's loud and you can watch the speedo drop.

I've never done anything near this before but I figure why not do one of the simplest and most common when I get a chance.

What's the deal with the clutches, hydraulic and mechanical? Their plumbing much different?
 
I put a 6.2L into an SM465 equiped truck that originally had a 350 V8 gas motor. The only thing that I changed was the flywheel, radiator, and a little of the wiring. Putting a 465 in place of a TH400 with factory parts will be a direct bolt in. You will have to drill a couple holes and cut out the shifter hole but GM was kind enough to put knockouts in those locations.
 
Very big difference between hydro and mechanical clutches. The hydro bits have a master cylinder that is bolted onto the firewall, and has their own specific pedals to match. A mechanical linkage has a rod that goes through the floor of the truck, their own pedals, a Z-bar linkage, and some bracketry on the frame.

The effort difference between a mechanical and hydraulic system is huge, hydro is way easier to actuate. Also, if you do any serious wheeling, you'll find that flexing your truck out in certain ways will cause the clutch to either disengage at the worst of times, or to be impossible to disengage, again at the very worst possible moment. Hydro always works, no matter how twisted up your truck is offroad.
 
once again AJM i find our thoughts drifting in similar directions...

i have already begun my parts gathering for this same swap. I found a 10spline 465-205 combo from a friend (for 80 bucks!!) and have picked up the diesel specific flywheel too.

my 400-205 combo is 3" longer than the Sm465-205, but that isnt too bad. Not sure what the 208 does for your drivetrain lengths.

The only real difference between a gasser 465 install and a diesel one is the flywheel. The diesel one is HEAVY and toothed differently for the diesel starter.

i plan on going with a hydraulic master and slave on an originally mechanical 465, just need to fab a bracket for the slave and drill a hole or two for the master.

I havent really got the clutch pedal thing figured out yet, i have been focusing on getting my new Dana 60 under the truck, but accomplished that on friday so i can now move on to this project.

i will post any info i discover and use this thread to post updates and insights as i go along.

Rick
 
Sounds like a plan. Sounds like hydraulic is definitely the way to go. When did that replace mechanical?



Here's really hypothetical...anybody know if the 24v CUCV starter would work with the SM465 diesel flywheel or would I need to convert to 12v in order to use a different starter?
 
I haven't dealt with military equipment any, but I can't see them having a different tooth count than the civilian 12V starter, should work just fine with the manual flywheel. Worst case scenario you have to grind the opening for the starter on the bellhousing a bit. Its made of aluminum, and is easy to grind.

85 is when the hydraulic clutch was introduced, used through 87 in the pickups, and 91 in the burbs, K5s, and 3+3s
 
So the ideal candidate would be a 85-87 pickup or 85-91 K5, Burb, or Crewcab to get all of the parts.
 
Well...now that we have it narrowed down to a diminishing window of rather desirable trucks why don't you just kick me in the junk?:crazy::wink1::doah:

Oh well, maybe someone parts a crewcab after stealing the axles.
 
Heh...yeah right.

They were either eaten alive and are gone.

or

Ended up as some sort of redneckerific hack job parts cobbled together abortion.

or

They're in pristine to moderate shape and the owner still wants too much for them and I'd feel bad paying that much for a parts vehicle.

Most of the yards up here have long since scrapped all of our body style trucks. When I needed a p-side seatbelt a few years ago I ended up looking fruitlessly for 2 weeks through all the local yards and then finally someone clued me into a small "yard" a wrecker owner keeps and doesn't advertise much almost 2 hours from here. Amazingly he had the right color even.

At any rate I wouldn't do this until after we've moved south. God willing that will be this year.



Where's Rene and Colby? They've both done these swaps too.
 
Sorry, been busy lately. Looks like you have most of the info you need. What you don't need is a complete truck, which will be a lot easier for you.

In cab what you'll need:

Pedal hanger assembly for a hydro clutch truck. I have a spare set-up. Cut hole for shifter boot, source shfter boot (both easy.)

What you need for the 6.2:

Flywheel (do not get a dual mass flywheel!)
Clutch disc, pressure plate, pilot bearing.

The rest:

Hydro bellhousing for a SM 465 (I have one I'm not gonna be using)
SM465 and whichever T-case you want. Frankly you could use your existing 208 as it's already 32 spline, as long as you find a 465 that's '81 or newer. You'll need to move the tranny crossmember a little...but that's just redrilling mount holes on the frame.

You'll just have to get over the fact you'll be altering both driveshafts. It's not as expensive as you might think..I've had em done for under $100 each.

By far the most 'asshole' part of the job is swapping the pedal hanger assembly. I ended up pulling the entire steering column out of the truck...

Rene
 
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