Want to make my tranny automatic and have questions? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71GMCNC · 01-31-2010, 08:12 PM

Ok guys, I did the search and came up with stuff to turn a auto into a manual but would like what all is involved to go manual to auto. I have an 83 K10 with a TH400 4 speed with granny gear. I want to go to Automatic and was wondering how to do so. I assume I would have to get an automatic tranny but what else would have to be done? Thanks for your knowledge and input!

dan76 · 01-31-2010, 08:40 PM

Do you want a stock appearance? If so you'll have to acquire an auto steering column with the appropriate linkage to the trans and either change out the pedal assembly or just pull the clutch pedal (but you can keep it in place). Additionally you'll need a plate to cover the hole in the floor (where the shifter previously resided). Don't forget the vacuum line to the trans modulator (if so equipped) and most likely you'll have to modify the driveshaft to match the selected trans and transfer case. Another item you'll need to look at is the crossmember......your existing one may work with a mod or two. You'll also need a radiator equipped with a trans cooler, flex plate and torque convertor. This is excellent time to get into an OD trans. Ideally you'll find a similar parts truck equipped with an auto and start swapping parts. Good luck and post pics of your work.

**DPowers** · 01-31-2010, 09:14 PM

Isnt a TH400 an automatic???

big10ratrod77 · 01-31-2010, 09:55 PM

and a sm465 a granny gear transmission?

71GMCNC · 02-01-2010, 01:25 PM

Yeah i found out it's a Muncie sm465 trans. I am currently looking at all the pic and pulls for a truck that is an auto 4x4 but so far they have been picked over. I think I may just keep it the way it is, come to find out alot of people in my area would love to have my setup.

spinem · 02-01-2010, 03:18 PM

Quote:

Originally Posted by 71GMCNC

Yeah i found out it's a Muncie sm465 trans. I am currently looking at all the pic and pulls for a truck that is an auto 4x4 but so far they have been picked over. I think I may just keep it the way it is, come to find out alot of people in my area would love to have my setup.

01-31-2010, 08:12 PM	#1
71GMCNC Registered User Join Date: Jun 2009 Location: ELIZABETH CITY, NC Posts: 51	Want to make my tranny automatic and have questions? Ok guys, I did the search and came up with stuff to turn a auto into a manual but would like what all is involved to go manual to auto. I have an 83 K10 with a TH400 4 speed with granny gear. I want to go to Automatic and was wondering how to do so. I assume I would have to get an automatic tranny but what else would have to be done? Thanks for your knowledge and input! __________________ '98 Chevy K1500 ext Cab Z71 4x4 196k miles and still going! 83' Chevy K10 Longbed 4x4. Dana 44 front and rear axles. Lift with 35's. Hopped up 350 V8, 4 speed manual w/granny. NP208 Transfer case SOLD!!!! '71 GMC Shortbed 350 V8/Edelbrock performer intake and carb/Custom Dual Flowmaster 40 Exhaust Currently in progress eventually 383 Stroker! SOLD!!!! '67 Chevy C20 londbed Original 327 V8/4 Speed Custom Cherry bomb Exhaust Inline to be next project sporitng primer grey SOLD!!!!!

01-31-2010, 08:40 PM	#2
dan76 Registered User Join Date: Mar 2008 Location: Salt Lake City UT Posts: 441	Re: Want to make my tranny automatic and have questions? Do you want a stock appearance? If so you'll have to acquire an auto steering column with the appropriate linkage to the trans and either change out the pedal assembly or just pull the clutch pedal (but you can keep it in place). Additionally you'll need a plate to cover the hole in the floor (where the shifter previously resided). Don't forget the vacuum line to the trans modulator (if so equipped) and most likely you'll have to modify the driveshaft to match the selected trans and transfer case. Another item you'll need to look at is the crossmember......your existing one may work with a mod or two. You'll also need a radiator equipped with a trans cooler, flex plate and torque convertor. This is excellent time to get into an OD trans. Ideally you'll find a similar parts truck equipped with an auto and start swapping parts. Good luck and post pics of your work.

01-31-2010, 09:14 PM	#3
DPowers One foot in front of the other Join Date: Aug 2008 Location: Parrottsville, TN Posts: 5,440	Re: Want to make my tranny automatic and have questions? Isnt a TH400 an automatic???

01-31-2010, 09:55 PM	#4
big10ratrod77 Registered User Join Date: Aug 2009 Location: hillborough nc Posts: 410	Re: Want to make my tranny automatic and have questions? and a sm465 a granny gear transmission? __________________ 77 chevy BIG 10 350/sm465/12bolt w 3.73 bout 240 horse power NO power steerin 79 chevy 1/2 ton 250/three on the tree/3.08s soon to get built 250/floor shift conversion/3.08s 81 mercedes 300d 25 MPG 77 chevy BIG DOOLEY 454/sm-465/14 bolt 4.10s "fully loaded" 73 plymouth duster 225 slant six/230 3 speed/8 1/4 trying to acheve 300 horse six http://www.cardomain.com/ride/3135091 '77 chevy trucks. built to stay tough. life is short build a hot rod

02-01-2010, 01:25 PM	#5
71GMCNC Registered User Join Date: Jun 2009 Location: ELIZABETH CITY, NC Posts: 51	Re: Want to make my tranny automatic and have questions? Yeah i found out it's a Muncie sm465 trans. I am currently looking at all the pic and pulls for a truck that is an auto 4x4 but so far they have been picked over. I think I may just keep it the way it is, come to find out alot of people in my area would love to have my setup. __________________ '98 Chevy K1500 ext Cab Z71 4x4 196k miles and still going! 83' Chevy K10 Longbed 4x4. Dana 44 front and rear axles. Lift with 35's. Hopped up 350 V8, 4 speed manual w/granny. NP208 Transfer case SOLD!!!! '71 GMC Shortbed 350 V8/Edelbrock performer intake and carb/Custom Dual Flowmaster 40 Exhaust Currently in progress eventually 383 Stroker! SOLD!!!! '67 Chevy C20 londbed Original 327 V8/4 Speed Custom Cherry bomb Exhaust Inline to be next project sporitng primer grey SOLD!!!!!

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