67 GMC small block 350... want to convert to auto trans - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mneuen · 07-06-2004, 03:05 AM

I've got a long bed 67 GMC with a small block 350 in it. I want to change to an automatic transmission without changing the crossmember... Is that possible or what are the alternatives. Any help will be MUCH appreciated! Thanks!

krue · 07-06-2004, 03:30 AM

I am not sure if you can put an auto tranny in without the crossmember, the tranny is gonna need the support. If it can be done, someone on here knows how to do it.

Welcome to the board from South Mississippi!

Tx Firefighter · 07-06-2004, 07:03 AM

You're going to have to pull the stock standard trans crossmember and use an automatic trans crossmember.

If you're pretty mean with a grinder and sawzall, that standard crossmember takes about 10 minutes to remove. I just pulled mine awhile back when I did this swap.

mneuen · 07-06-2004, 09:21 AM

Thanks guys! OK how about this... my friend says a powerglide will fit onto the existing crossmember. What do you think about that?

OK OK What would you use if you were putting an automatic trans on there?

Willy Prost · 07-06-2004, 09:47 AM

Original standard shift trucks have a crossmsmber of sorts that bolts to the bellhousing. Use a auto transmission crossmember. Either get a used one from one of the board members or buy a new one from Early Classic Enterprises.
http://www.earlyclassic.com/index.html

stllookn · 07-06-2004, 01:44 PM

Powerglide will need the standard auto tranny crossmember...at mine does! I don't see any other way to mount it.

busterwivell · 07-06-2004, 04:09 PM

You SURE you want a Powerglide? Personally, I wouldn't. I went from a truck 4 speed to a 700R4 and couldn't be happier. Took a custom crossmember, but it was worth it.

Quagmire · 07-06-2004, 09:33 PM

if you get up underneath your truck and take a look versus one with an auto, you will see why everyone is telling you 'no, it won't work'.

i'll tell you the same thing. the standard trannys are shorter than any auto for one. the crossmembers for the standard bolts up at the bellhousing (towards the front of the transmission) while the autos will bolt up towards the rear of the tranny. also, the crosssmembers aren't the same, you will need one for an auto or buy/build a universal one

mneuen · 07-07-2004, 12:16 AM

Thank you to everyone! I have been up underneath that thing for going on three days (oil leaks... that seems silly... the oil doesn't leak; it flows quite freely out of every possible place) and majority says to go with the 700R4 or the TH350... so again, thanks for all the info. That's good stuff! I'll keep this thread posted on the happenings.

07-06-2004, 03:05 AM	#1
mneuen Registered User Join Date: Jul 2004 Posts: 6	67 GMC small block 350... want to convert to auto trans I've got a long bed 67 GMC with a small block 350 in it. I want to change to an automatic transmission without changing the crossmember... Is that possible or what are the alternatives. Any help will be MUCH appreciated! Thanks! Last edited by mneuen; 07-06-2004 at 09:19 AM.

07-06-2004, 03:30 AM	#2
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	I am not sure if you can put an auto tranny in without the crossmember, the tranny is gonna need the support. If it can be done, someone on here knows how to do it. Welcome to the board from South Mississippi! __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

07-06-2004, 07:03 AM	#3
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	You're going to have to pull the stock standard trans crossmember and use an automatic trans crossmember. If you're pretty mean with a grinder and sawzall, that standard crossmember takes about 10 minutes to remove. I just pulled mine awhile back when I did this swap. __________________ I'm on the Instagram- @Gearhead_Kevin

07-06-2004, 09:21 AM	#4
mneuen Registered User Join Date: Jul 2004 Posts: 6	Thanks guys! OK how about this... my friend says a powerglide will fit onto the existing crossmember. What do you think about that? OK OK What would you use if you were putting an automatic trans on there? Last edited by mneuen; 07-06-2004 at 09:32 AM.

07-06-2004, 01:44 PM	#6
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Powerglide will need the standard auto tranny crossmember...at mine does! I don't see any other way to mount it. __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

07-06-2004, 09:47 AM	#5
Willy Prost Senior Member Join Date: Jan 2000 Location: Arlington, VA Posts: 398	Original standard shift trucks have a crossmsmber of sorts that bolts to the bellhousing. Use a auto transmission crossmember. Either get a used one from one of the board members or buy a new one from Early Classic Enterprises. http://www.earlyclassic.com/index.html

07-06-2004, 04:09 PM	#7
busterwivell Registered User Join Date: Jan 2002 Location: Sahuarita, AZ USA Posts: 2,033	You SURE you want a Powerglide? Personally, I wouldn't. I went from a truck 4 speed to a 700R4 and couldn't be happier. Took a custom crossmember, but it was worth it. __________________ Bill - Tucson, AZ 47 Chevrolet 2 dr sedan 56 Chevrolet 210 2 dr sedan 66 Chevrolet Malibu 2 dr 4 speed 71 Chevrolet C30 Longhorn 86 Chevrolet Monte Carlo SS (Sold) 01 Chevrolet Tahoe IM - BUSTERWIVE@aol.com

07-06-2004, 09:33 PM	#8
Quagmire A splendid one to behold Join Date: Jan 2004 Location: moore, ok Posts: 251	if you get up underneath your truck and take a look versus one with an auto, you will see why everyone is telling you 'no, it won't work'. i'll tell you the same thing. the standard trannys are shorter than any auto for one. the crossmembers for the standard bolts up at the bellhousing (towards the front of the transmission) while the autos will bolt up towards the rear of the tranny. also, the crosssmembers aren't the same, you will need one for an auto or buy/build a universal one __________________ 67 swb 02 wrx

07-07-2004, 12:16 AM	#9
mneuen Registered User Join Date: Jul 2004 Posts: 6	Thank you to everyone! I have been up underneath that thing for going on three days (oil leaks... that seems silly... the oil doesn't leak; it flows quite freely out of every possible place) and majority says to go with the 700R4 or the TH350... so again, thanks for all the info. That's good stuff! I'll keep this thread posted on the happenings.



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