Changing 4 speed to auto. What else do I need ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikep · 01-20-2003, 02:23 AM

I'm changing from my NP 435 4 speed to a turbo 350. Ive got a used but serviceable turbo 350, a new filter kit, a rear mount, a new set of seals, a new torque converter, a B&M shift kit, a Lokar shifter, and an automatic crossmember . What else will I need. I havent measured the OAL on the turbo 350 and the NP435 yet but I assume I'll need a different front driveshaft and a different transmission yoke from the junkyard . Anything I am forgetting? I know I need a flexplate too.

Blue_71 · 01-20-2003, 02:42 AM

auto crossmember, steering column, shifter linkages, shifter handle

MR. GOODWRENCH · 01-20-2003, 02:47 AM

you'll need a flexplate too.

MR. GOODWRENCH · 01-20-2003, 02:48 AM

sorry I didn't see your last few words in your post

mikep · 01-20-2003, 03:19 AM

I do have a Lokar shifter so that whole column thing I wont need. Nice piece too. Much better than one of those rickety B&M or other aftermarket jobs and I can use the original shifter boot.

Blue_71 · 01-20-2003, 03:26 AM

ok knock my list down to just crossmember

jays68yak · 01-20-2003, 03:33 AM

Starter if yours from the stick bolts to the bell housing.....

hughnews1 · 01-20-2003, 08:00 AM

??? What is a flexplate ? for the hole in the flooor ?

jays68yak · 01-20-2003, 11:33 AM

the flexplate will replace the flywheel (the big metal spinning thingy that the clutch is bolted too) and has the gear on it to start the motor

crazy longhorn · 01-20-2003, 12:37 PM

You will need to strap your left boot to the floor for a while........it will tend to have its own memory about the 'intimate relationship"with the clutch peddle

.......crazyL

mikep · 01-20-2003, 12:51 PM

Ive got the crossmember and I'll pick up a flexplate this week. What about the driveshaft. Anyone had any experience doing this?

I can see my left foot trying to stab the floor already.

swdobbs · 01-20-2003, 03:26 PM

I just got done swapping in a TH400 short shaft.

The parts I forgot were a different starter (the old one bolted to the bellhousing, and a aftermarket tranny cooler (I didn't have the $ for a auto radiator.

Lol, swdobbs...........

Rod · 01-21-2003, 12:25 AM

Some tips here.
http://67-72chevytrucks.com/tech/trannyswap.html

mikep · 01-21-2003, 12:54 AM

OK does anyone know if the TH350 transmission yolk is the same as the 4 speeds? I'd hate to go down and spend a few hours digging one out of the junkyard to find out the TH 350 and the 4 speed have the same yolk and first driveshaft.

crazy longhorn · 01-21-2003, 01:03 AM

I dont know about that NP 435, but the 350 t has the same yolk as a sag 3 or 4 spd, or a M20/21 muncie, or a powerglide.....

mikep · 01-21-2003, 01:24 AM

Well I'm pretty sure the only difference between the run of the mill NP 465 and the NP 435 is the ratios of the gear set so if anyone can tell me if regular old truck chevy 4 speeds are the same yolk as TH350's I would be most appreciative.

Blue_71 · 01-21-2003, 01:33 AM

SM465 (granny gear unsynchronized 1st) wont go with a TH350/3 speed driveshaft, mine wont anyways... not with the yolk thats on the 4 speed, i havent tried taking it off though

crazy longhorn · 01-21-2003, 11:26 AM

Mike, one of the guys posted this site in a different thread,& it had lengths & info on the different 4 spd truck trannys,as well as info on the auto trannys......lenghts on the autos were figured on 4wd app (i beleive)..... http://www.novak-adapt.com/knowledge...on_gateway.htm At any rate, i think your 4 spd will be a bunch shorter than the 350 T, & due to the BB stands/eng position your best bet would probably be to pick up a slip yolk & have your shaft cut & balanced. good luck.....crazyL

mikep · 01-21-2003, 02:22 PM

Thats great info. I had always assumed the NP 435 to be the same build of transmission as the 465 except for the gearing. Its not. Not even close. The 465 is a Muncie tranny . Mines a New Process. Duh ! Their info doesnt cover the tailshaft housing like I Looks like I'm going to have to go out in the rain today and take some measurements. My first gear ratio also isnt one they have listed. I dont think there were many of these made for our trucks.

jays68yak · 01-21-2003, 03:50 PM

I dont know how many of them were made in these trucks. But it does look like they are hard to find out info on.
I have one of the NP435 s on ebay right now.
Good luck with the swap.

mikep · 01-21-2003, 09:01 PM

More annoying 4 speed to automatic trivia...

By my measurements the TH 350 is 29 inches long to the tailshaft end.

The NP 435 is 20.5 inches long from bellhousing/block mating surface to the end of the tailshaft.

That means that I need a driveshaft that is 8.5 inches shorter than the driveshaft I currently have. My driveshaft is 36 inches long from the center of the U joint to the carrier bearing center. This of course means that I need a driveshaft that is 27.5 or so inches long ( plus or minus an inch ) from the center of the front U joint to the carrier bearing.

Could somebody with a Turbo 400 transmission please tell me how long your front driveshaft is fron the center of the U joint to the carrier bearing. I'm talking about the carrier bearing here . Not the end of the front drivshaft. Just to the carrier bearing. I am thinking that the TH 400 driveshaft might be the one I need but I'd like to get some confirmation before i start tearing into things in the really cold mud of the junkyard. I know I need a 350 yoke but the front drivshaft is what I am concerened with.

Thanks

mikep · 01-21-2003, 11:35 PM

please

**breeh** · 01-21-2003, 11:44 PM

Why don't you just have your current shaft cut and balanced? It seems like it would save you some agony and I have paid about $50.00 to have this done in the past.

mikep · 01-21-2003, 11:54 PM

Because I'd be doing it twice. No fun. Remember I'll be cutting the frame and or installing a short frame this summer then I'll have to do it all over again. If I can find a suitable shorter than mine drive shaft I'll try that first.

Mike

**breeh** · 01-21-2003, 11:58 PM

OK, I knew there had to be a reason

01-20-2003, 02:23 AM	#1
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Changing 4 speed to auto. What else do I need ? I'm changing from my NP 435 4 speed to a turbo 350. Ive got a used but serviceable turbo 350, a new filter kit, a rear mount, a new set of seals, a new torque converter, a B&M shift kit, a Lokar shifter, and an automatic crossmember . What else will I need. I havent measured the OAL on the turbo 350 and the NP435 yet but I assume I'll need a different front driveshaft and a different transmission yoke from the junkyard . Anything I am forgetting? I know I need a flexplate too. __________________ No truck :-( Last edited by mikep; 01-20-2003 at 02:29 AM.

01-20-2003, 02:47 AM	#3
MR. GOODWRENCH Registered User Join Date: Jan 2003 Location: Maryville,TN Posts: 402	you'll need a flexplate too. __________________ 68 CST SWB,full off frame restoration,72 GMC Sierra Grande SWB,72 Cheyenne 30 long wheelbase flatbed,2000 4door Chevy Dually bought new,2002 SS Camaro with 600 miles,bought it to put up,72 Monte Carlo,it was my first car,69 Impala with 50,000 miles,it was my dads,89 Dodge diseal 3/4 ton 4 wheel drive,my dad bought it new,68 Camaro RS dragcar,97 United Transporters 25 foot enclosed trailer,58 Oliver Super 77 Diseal,my grandfather bought new fully restored,55 Oliver Super 66 Diseal my uncle bought new,49 Oliver Rowcrop 88,51 Farmall H,51 Farmall Super C,81 Ford 3600,89 Ford 6610,49 Allis Chalmers WD45,81 Allis Chalmers 7060 my dad bought new,Allis Chalmers 175.

01-20-2003, 02:48 AM	#4
MR. GOODWRENCH Registered User Join Date: Jan 2003 Location: Maryville,TN Posts: 402	sorry I didn't see your last few words in your post __________________ 68 CST SWB,full off frame restoration,72 GMC Sierra Grande SWB,72 Cheyenne 30 long wheelbase flatbed,2000 4door Chevy Dually bought new,2002 SS Camaro with 600 miles,bought it to put up,72 Monte Carlo,it was my first car,69 Impala with 50,000 miles,it was my dads,89 Dodge diseal 3/4 ton 4 wheel drive,my dad bought it new,68 Camaro RS dragcar,97 United Transporters 25 foot enclosed trailer,58 Oliver Super 77 Diseal,my grandfather bought new fully restored,55 Oliver Super 66 Diseal my uncle bought new,49 Oliver Rowcrop 88,51 Farmall H,51 Farmall Super C,81 Ford 3600,89 Ford 6610,49 Allis Chalmers WD45,81 Allis Chalmers 7060 my dad bought new,Allis Chalmers 175.

01-20-2003, 03:19 AM	#5
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I do have a Lokar shifter so that whole column thing I wont need. Nice piece too. Much better than one of those rickety B&M or other aftermarket jobs and I can use the original shifter boot. __________________ No truck :-(

01-20-2003, 03:33 AM	#7
jays68yak Registered User Join Date: Oct 2002 Location: Gilroy, CA Posts: 1,454	Starter if yours from the stick bolts to the bell housing..... __________________ 1969 Chevy Project SWB Fleet, 20s, 5.3, t56, in the weeds. 1970 Chevy Truck cab on a 1979 Jimmy frame-8.1 liter 496 bbc/sm465/np203-jeds doubler-np205/d60/14bff Welded/42 tsls on recentered H1s 1998 Chevy Crew Cab K3500 SAS'd with hpd60, links and swayaway coilovers. 8.1l vortec DD/towrig "I like long walks, especially when they are taken by people who annoy me. "

01-20-2003, 03:26 AM	#6
Blue_71 Bloo Join Date: Feb 2001 Location: Barren County Kentucky Posts: 6,285	ok knock my list down to just crossmember

01-20-2003, 08:00 AM	#8
hughnews1 Registered User Join Date: Apr 2002 Location: Hudson FL gulf coast Posts: 624	??? What is a flexplate ? for the hole in the flooor ?

01-20-2003, 11:33 AM	#9
jays68yak Registered User Join Date: Oct 2002 Location: Gilroy, CA Posts: 1,454	the flexplate will replace the flywheel (the big metal spinning thingy that the clutch is bolted too) and has the gear on it to start the motor __________________ 1969 Chevy Project SWB Fleet, 20s, 5.3, t56, in the weeds. 1970 Chevy Truck cab on a 1979 Jimmy frame-8.1 liter 496 bbc/sm465/np203-jeds doubler-np205/d60/14bff Welded/42 tsls on recentered H1s 1998 Chevy Crew Cab K3500 SAS'd with hpd60, links and swayaway coilovers. 8.1l vortec DD/towrig "I like long walks, especially when they are taken by people who annoy me. "

01-20-2003, 12:37 PM	#10
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	You will need to strap your left boot to the floor for a while........it will tend to have its own memory about the 'intimate relationship"with the clutch peddle .......crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

01-20-2003, 12:51 PM	#11
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Ive got the crossmember and I'll pick up a flexplate this week. What about the driveshaft. Anyone had any experience doing this? I can see my left foot trying to stab the floor already. __________________ No truck :-(

01-20-2003, 03:26 PM	#12
swdobbs Registered User Join Date: Oct 2002 Location: MT Posts: 98	Swap parts I just got done swapping in a TH400 short shaft. The parts I forgot were a different starter (the old one bolted to the bellhousing, and a aftermarket tranny cooler (I didn't have the $ for a auto radiator. Lol, swdobbs...........

01-21-2003, 12:25 AM	#13
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Some tips here. http://67-72chevytrucks.com/tech/trannyswap.html __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

01-21-2003, 12:54 AM	#14
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	OK does anyone know if the TH350 transmission yolk is the same as the 4 speeds? I'd hate to go down and spend a few hours digging one out of the junkyard to find out the TH 350 and the 4 speed have the same yolk and first driveshaft. __________________ No truck :-( Last edited by mikep; 01-21-2003 at 01:11 AM.

01-21-2003, 01:03 AM	#15
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	I dont know about that NP 435, but the 350 t has the same yolk as a sag 3 or 4 spd, or a M20/21 muncie, or a powerglide..... __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

01-21-2003, 01:24 AM	#16
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Well I'm pretty sure the only difference between the run of the mill NP 465 and the NP 435 is the ratios of the gear set so if anyone can tell me if regular old truck chevy 4 speeds are the same yolk as TH350's I would be most appreciative. __________________ No truck :-(



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01-21-2003, 11:26 AM	#18
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Mike, one of the guys posted this site in a different thread,& it had lengths & info on the different 4 spd truck trannys,as well as info on the auto trannys......lenghts on the autos were figured on 4wd app (i beleive)..... http://www.novak-adapt.com/knowledge...on_gateway.htm At any rate, i think your 4 spd will be a bunch shorter than the 350 T, & due to the BB stands/eng position your best bet would probably be to pick up a slip yolk & have your shaft cut & balanced. good luck.....crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

01-21-2003, 02:22 PM	#19
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Thats great info. I had always assumed the NP 435 to be the same build of transmission as the 465 except for the gearing. Its not. Not even close. The 465 is a Muncie tranny . Mines a New Process. Duh ! Their info doesnt cover the tailshaft housing like I Looks like I'm going to have to go out in the rain today and take some measurements. My first gear ratio also isnt one they have listed. I dont think there were many of these made for our trucks. __________________ No truck :-(

01-21-2003, 03:50 PM	#20
jays68yak Registered User Join Date: Oct 2002 Location: Gilroy, CA Posts: 1,454	I dont know how many of them were made in these trucks. But it does look like they are hard to find out info on. I have one of the NP435 s on ebay right now. Good luck with the swap. __________________ 1969 Chevy Project SWB Fleet, 20s, 5.3, t56, in the weeds. 1970 Chevy Truck cab on a 1979 Jimmy frame-8.1 liter 496 bbc/sm465/np203-jeds doubler-np205/d60/14bff Welded/42 tsls on recentered H1s 1998 Chevy Crew Cab K3500 SAS'd with hpd60, links and swayaway coilovers. 8.1l vortec DD/towrig "I like long walks, especially when they are taken by people who annoy me. "

01-21-2003, 09:01 PM	#21
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	More annoying 4 speed to automatic trivia... By my measurements the TH 350 is 29 inches long to the tailshaft end. The NP 435 is 20.5 inches long from bellhousing/block mating surface to the end of the tailshaft. That means that I need a driveshaft that is 8.5 inches shorter than the driveshaft I currently have. My driveshaft is 36 inches long from the center of the U joint to the carrier bearing center. This of course means that I need a driveshaft that is 27.5 or so inches long ( plus or minus an inch ) from the center of the front U joint to the carrier bearing. Could somebody with a Turbo 400 transmission please tell me how long your front driveshaft is fron the center of the U joint to the carrier bearing. I'm talking about the carrier bearing here . Not the end of the front drivshaft. Just to the carrier bearing. I am thinking that the TH 400 driveshaft might be the one I need but I'd like to get some confirmation before i start tearing into things in the really cold mud of the junkyard. I know I need a 350 yoke but the front drivshaft is what I am concerened with. Thanks __________________ No truck :-(

01-21-2003, 11:35 PM	#22
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	help please __________________ No truck :-(

01-21-2003, 11:44 PM	#23
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	Why don't you just have your current shaft cut and balanced? It seems like it would save you some agony and I have paid about $50.00 to have this done in the past. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

01-21-2003, 11:54 PM	#24
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Because I'd be doing it twice. No fun. Remember I'll be cutting the frame and or installing a short frame this summer then I'll have to do it all over again. If I can find a suitable shorter than mine drive shaft I'll try that first. Mike __________________ No truck :-(

01-21-2003, 11:58 PM	#25
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	OK, I knew there had to be a reason __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

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