I hate automatics - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OLDBLUE76 · 06-27-2011, 03:38 PM

I have a question for you all. How hard is it to change a truck from an automatic to a manual transmission? I currently have an 82 1/2 ton 4WD with a 350 motor and a 350 transmission, I also have an 83 1/2 ton 2WD with a three speed transmission and a 250 motor. The 3 speed used to be on the column and the previous owner put a floor shift kit in. I would like to see the manual transmission in the the 4WD truck. Anyone ever done anything like this? I'm not a fan of automatic transmissions, but GM was back in the 70's and 80's so finding one of the stick shift trucks is hard. I would like to know what you all think or have done. Thanks for a cool forum also, this is my first post.

xrcr · 06-27-2011, 03:47 PM

I've only gone from manual to auto. Obviously the pedal setup, tranny,crossmember and driveshaft will be different. You have all the parts i would think the only thing I'm clueless on would be the transfer case and what if any issue that would raise. There are a lot of smart folks on here that will hook You up and I'll get some more info too.
Welcome to the site.
xrcr

MadManAndrew · 06-27-2011, 03:56 PM

You need a 4wd tailshaft, I believe. I'm not sure as I've never worked with manuals, but I'm pretty sure the tailshafts should still be different. You can order all the parts to convert from a tranny shop, and then you'll also need a 350/3-speed combo specific flywheel. All the other parts you should already have.

LONGHAIR · 06-27-2011, 07:41 PM

You will be far better off to find a proper 4x4 transmission/transfercase. Trying to "adapt" the 3 speed is going to cost you more in both time and money than it's worth. I may be possible.....but why?

**hatzie** · 06-27-2011, 08:57 PM

The Three On The Tree Saginaw isn't a 4x4 gearbox and can't be made into one for less than a NV4500 conversion would cost.

If your goal is to convert the truck to 2WD then go for it. It's a bolt-in job.

If you want to keep your 4WD. It'd be far less money to craigslist a good SM465 with it's own transfer case. In the $200-$400 range sometimes less. I've seen listings for the whole shebang bellhousing, SM465 tranny, NP205 T case, sticks, and pedals for $100.

If you need them... the PITA to find parts from the pedals to the bellhousing should work from the 3 speed truck.

bscman · 06-27-2011, 11:41 PM

Your 2wd/3spd parts will not work for this swap...

Any way you look at it, it is a pretty in-depth swap.

Best bet is to find a complete SM465 + transfer case, as your current transfercase will NOT mate with the either 10spline or 32 spline output shaft on the new 4spd.
The SM465 came in front of several transfer cases, but your best bet if you're going through the work is to get the strongest case possible...the NP205. Very common. I've purchased three SM465's mated to NP205's in the last year, the most expensive being $200.

You'll need a bellhousing, flywheel, shift linkage, etc.
You'll also need the complete pedal assembly from a manual transmission truck. You'll probably want the steering column, too...to get rid of the column shifter for your current automatic.

The crossmember for the SM465 is the same, but will need to be moved 3/4" from it's location with the Th350.

Not know what transfer case you have currently (Assuming NP208?), I can't speak for how this will affect your driveshaft lengths...but I would assume you will need a front driveshaft that is SHORTER, as the SM465 is very short in length. Your rear shaft will likely need lengthened...which is more expensive than shortening!

You could easily get *MOST* of the parts used, for under $400...but you'll have plenty of time into cleaning, resealing, repairing...then there are things like clutch kits and flywheels that should be purchased new in my opinion.

All and all, you're looking at a LONG process with plenty of cussing.
I'd suggest a ratchet shifter, and a good transpak for better manual control of the transmission so you can upshift downshift as necessary. Spend a few bucks on an adjustable modulator and a governer weight/spring kit so you can tailor shift points.
I agree auto's suck in 4x4's...but with a small investment you can make your auto a WHOLE lot more functional and less aggravating to drive.

06-27-2011, 03:38 PM	#1
OLDBLUE76 Registered User Join Date: Jun 2011 Location: IL Posts: 2	I hate automatics I have a question for you all. How hard is it to change a truck from an automatic to a manual transmission? I currently have an 82 1/2 ton 4WD with a 350 motor and a 350 transmission, I also have an 83 1/2 ton 2WD with a three speed transmission and a 250 motor. The 3 speed used to be on the column and the previous owner put a floor shift kit in. I would like to see the manual transmission in the the 4WD truck. Anyone ever done anything like this? I'm not a fan of automatic transmissions, but GM was back in the 70's and 80's so finding one of the stick shift trucks is hard. I would like to know what you all think or have done. Thanks for a cool forum also, this is my first post.

06-27-2011, 03:47 PM	#2
xrcr Registered User Join Date: Dec 2008 Location: Foristell, MO Posts: 418	Re: I hate automatics I've only gone from manual to auto. Obviously the pedal setup, tranny,crossmember and driveshaft will be different. You have all the parts i would think the only thing I'm clueless on would be the transfer case and what if any issue that would raise. There are a lot of smart folks on here that will hook You up and I'll get some more info too. Welcome to the site. xrcr

06-27-2011, 03:56 PM	#3
MadManAndrew Registered User Join Date: Mar 2011 Location: Dallas, Texas Posts: 920	Re: I hate automatics You need a 4wd tailshaft, I believe. I'm not sure as I've never worked with manuals, but I'm pretty sure the tailshafts should still be different. You can order all the parts to convert from a tranny shop, and then you'll also need a 350/3-speed combo specific flywheel. All the other parts you should already have. __________________ 1955 Chevy 3600 http://67-72chevytrucks.com/vboard/s...61#post8589061 Last edited by MadManAndrew; 06-27-2011 at 03:56 PM.

06-27-2011, 08:57 PM	#5
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,962	Re: I hate automatics The Three On The Tree Saginaw isn't a 4x4 gearbox and can't be made into one for less than a NV4500 conversion would cost. If your goal is to convert the truck to 2WD then go for it. It's a bolt-in job. If you want to keep your 4WD. It'd be far less money to craigslist a good SM465 with it's own transfer case. In the $200-$400 range sometimes less. I've seen listings for the whole shebang bellhousing, SM465 tranny, NP205 T case, sticks, and pedals for $100. If you need them... the PITA to find parts from the pedals to the bellhousing should work from the 3 speed truck.

06-27-2011, 11:41 PM	#6
bscman Registered User Join Date: Jun 2011 Location: Sedro Wolley, WA Posts: 1	Re: I hate automatics Your 2wd/3spd parts will not work for this swap... Any way you look at it, it is a pretty in-depth swap. Best bet is to find a complete SM465 + transfer case, as your current transfercase will NOT mate with the either 10spline or 32 spline output shaft on the new 4spd. The SM465 came in front of several transfer cases, but your best bet if you're going through the work is to get the strongest case possible...the NP205. Very common. I've purchased three SM465's mated to NP205's in the last year, the most expensive being $200. You'll need a bellhousing, flywheel, shift linkage, etc. You'll also need the complete pedal assembly from a manual transmission truck. You'll probably want the steering column, too...to get rid of the column shifter for your current automatic. The crossmember for the SM465 is the same, but will need to be moved 3/4" from it's location with the Th350. Not know what transfer case you have currently (Assuming NP208?), I can't speak for how this will affect your driveshaft lengths...but I would assume you will need a front driveshaft that is SHORTER, as the SM465 is very short in length. Your rear shaft will likely need lengthened...which is more expensive than shortening! You could easily get MOST of the parts used, for under $400...but you'll have plenty of time into cleaning, resealing, repairing...then there are things like clutch kits and flywheels that should be purchased new in my opinion. All and all, you're looking at a LONG process with plenty of cussing. I'd suggest a ratchet shifter, and a good transpak for better manual control of the transmission so you can upshift downshift as necessary. Spend a few bucks on an adjustable modulator and a governer weight/spring kit so you can tailor shift points. I agree auto's suck in 4x4's...but with a small investment you can make your auto a WHOLE lot more functional and less aggravating to drive.



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