Converting a 4x4 stick to an automatic - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 06-09-2003, 11:23 PM

Can anyone shed some light on what's involved with converting a 4x4 4speed to an automatic? Is it basically the same as with a 2x4, any differences in auto trans between the two?

Any info is appreciated. Thanks!

**JIMs70GMC** · 06-10-2003, 05:20 AM

I'd suggest getting a 350/205 combo and just swap out the manual/transfercase combo you have. I'm not sure if the driveshafts will need to be modified or not. The big difference will be no tailshaft on the 4x4 auto that will need to mate up with the tc. If you try to use your original tc you might have to replace the tc input shaft. I recommend visiting ORDs and Advanced Adapters websites because they have good tech articles on this.

JimKshortstep4x4 · 06-10-2003, 07:45 AM

Going with a 350/205 combo as suggested is the way to go. The
driveshaft will fit as is. You will need an automatic column, shift linkage for a 4x4, kickdown cable bracket for mounting on the engine, a carb with the right pin on the linkage, a vacuum tree or vacuum source for the modulator, a radiator with built in cooler or
equivalent and transmission coolant lines.

It is not a hard swap except everything is so heavy!

Jim

bouncytruck · 06-10-2003, 12:31 PM

A previous owner converted my Blazer to an auto. They put in a TH350 with an NP203 t-case. I have a B&M shifter on the floor. I'd like to move the shifter back up to the column some day, but there are a lot of other things to do in the mean time. If you don't get the whole transmission/t-case combo, your probably going to need to get an adapter to mate the new transmission to the t-case. As suggested, advanced adapters will have what you need or you could look for a used one. You, need a transmission cooler or a new radiator with the transmission cooler and new pedals. Good luck.

Mudder · 06-10-2003, 12:49 PM

Flywheel? Also on my daughters Blazer going from a stick to a 350/203 both drive shafts had to be changed.

BUDDY · 06-10-2003, 04:34 PM

I'd swap you straight across, but here's the catch. I'm in Buffalo, NY and my truck isn't driveable right now. I'd rather have the four speed and around here they are hard to come by. If you'd be willing to meet me in my driveway, we can do the swap and get you down the road in a couple of days.

Let me know,

Buddy

**ScottH** · 06-10-2003, 09:20 PM

Buddy, I was inquiring about a truck I am considering buying. I'm not sure what I'm going to do yet, but if I do purchase it we can probably work something out.

Thanks to all.

BUDDY · 06-11-2003, 08:07 AM

no prob. I would be interested, let me know how it goes.

Buddy

mcmlxix · 06-11-2003, 09:53 AM

I am swaping out my sm465/np205 from my 1970 K5 CST Blazer. I bought an 88 K5 good running but rusty donor truck. (driver seat was falling throught he floor) I planned on taking the whole drive train. TBI 350, 700r4, NP208, disc front axle and matching rear. This way I have all the nuts bolt brackets and anything else I might need. I also get gray bucket seat and a back seat for my 70k5.

I am selling the SM46/NP205 with all the parts to swap. Pedels, crossmember, linkage, bellhousing, new clutch with like 8 miles on it and the fly wheel if I can find it and a pilot bearing for an auto to manual swap.

check out the for sale forum .. http://67-72chevytrucks.com/vboard/s...threadid=51840

06-09-2003, 11:23 PM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Converting a 4x4 stick to an automatic Can anyone shed some light on what's involved with converting a 4x4 4speed to an automatic? Is it basically the same as with a 2x4, any differences in auto trans between the two? Any info is appreciated. Thanks!

06-10-2003, 05:20 AM	#2
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I'd suggest getting a 350/205 combo and just swap out the manual/transfercase combo you have. I'm not sure if the driveshafts will need to be modified or not. The big difference will be no tailshaft on the 4x4 auto that will need to mate up with the tc. If you try to use your original tc you might have to replace the tc input shaft. I recommend visiting ORDs and Advanced Adapters websites because they have good tech articles on this. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

06-10-2003, 12:31 PM	#4
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,049	A previous owner converted my Blazer to an auto. They put in a TH350 with an NP203 t-case. I have a B&M shifter on the floor. I'd like to move the shifter back up to the column some day, but there are a lot of other things to do in the mean time. If you don't get the whole transmission/t-case combo, your probably going to need to get an adapter to mate the new transmission to the t-case. As suggested, advanced adapters will have what you need or you could look for a used one. You, need a transmission cooler or a new radiator with the transmission cooler and new pedals. Good luck. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

06-11-2003, 09:53 AM	#9
mcmlxix Collector of Projects Join Date: Apr 2003 Location: Las Vegas Posts: 3,106	I am swaping out my sm465/np205 from my 1970 K5 CST Blazer. I bought an 88 K5 good running but rusty donor truck. (driver seat was falling throught he floor) I planned on taking the whole drive train. TBI 350, 700r4, NP208, disc front axle and matching rear. This way I have all the nuts bolt brackets and anything else I might need. I also get gray bucket seat and a back seat for my 70k5. I am selling the SM46/NP205 with all the parts to swap. Pedels, crossmember, linkage, bellhousing, new clutch with like 8 miles on it and the fly wheel if I can find it and a pilot bearing for an auto to manual swap. check out the for sale forum .. http://67-72chevytrucks.com/vboard/s...threadid=51840 __________________ Rich 1972 K5 Blazer CST Click HERE D60 BIG BRAKE UPGRADE Click HERE

06-10-2003, 07:45 AM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Going with a 350/205 combo as suggested is the way to go. The driveshaft will fit as is. You will need an automatic column, shift linkage for a 4x4, kickdown cable bracket for mounting on the engine, a carb with the right pin on the linkage, a vacuum tree or vacuum source for the modulator, a radiator with built in cooler or equivalent and transmission coolant lines. It is not a hard swap except everything is so heavy! Jim

06-10-2003, 12:49 PM	#5
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Flywheel? Also on my daughters Blazer going from a stick to a 350/203 both drive shafts had to be changed.

06-10-2003, 04:34 PM	#6
BUDDY Global warming is a myth Join Date: Apr 2003 Location: Henderson, NV Posts: 208	I'd swap you straight across, but here's the catch. I'm in Buffalo, NY and my truck isn't driveable right now. I'd rather have the four speed and around here they are hard to come by. If you'd be willing to meet me in my driveway, we can do the swap and get you down the road in a couple of days. Let me know, Buddy

06-10-2003, 09:20 PM	#7
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Buddy, I was inquiring about a truck I am considering buying. I'm not sure what I'm going to do yet, but if I do purchase it we can probably work something out. Thanks to all.

06-11-2003, 08:07 AM	#8
BUDDY Global warming is a myth Join Date: Apr 2003 Location: Henderson, NV Posts: 208	no prob. I would be interested, let me know how it goes. Buddy



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