Th400 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70short · 11-10-2004, 03:57 PM

I want to install an Auto TH400 in place of my old truck 4-speed. I have A 69 donner truck for the swap. Do I need the crossmember out of the donner truck or will mine work? I looked at my crossmember and it looks like it will be A pain to drill the rivets (upper 4). There is not alot of room to drop bolts into the upper holes for the swap. Do I need to lift the CAB? I cant wait to finally get An "AUTO" in place of the "OLD TRUCK 4-SPEED" Any help would be greatly appreciated! THANK YOU!!!!!!!!!!!

Gary

john@thepier · 11-10-2004, 08:24 PM

depending on the cross member you have it will more than likely need to be swapped out.my 3 on the tree cross member had to be removed and replaced with a auto cross member.grinding and nocking out the rivets required me to have to un bolt the front of the cab and jack it up a little in order to fit my grinder in there.and that was after the engine and front clip was removed.soon I will be slipping in my new 400-400 combo GOOD-LUCK

JimKshortstep4x4 · 11-10-2004, 08:29 PM

You will need the auto cross member. If your cab mounts are bad you may need to lift the cab slightly to install the bolts, but I have not had a problem installing the upper bolts.

Hooter · 11-10-2004, 11:02 PM

you shouldnt need to lift the cab to accomodate the turbo 400, the 4 speed cab has a higher hump then an automatic cab anyways. Swap the crossmembers, by a new tranny mount for the crossmember because chances are the old one is toast anyways.

Tx Firefighter · 11-11-2004, 08:37 AM

Quick Tx Firefighter Easy Method (TM) of removing the manual crossmember with the cab still on. Using Sawz-all, cut the center of the crossmember out to where there are just 4 wings left riveted to the frame. Now, slice the rivet heads off with the sawz-all. You can sneak the saw blade on top of the frame, between the frame and cab and nip the heads right off. Now hit each wing with a sledge hammer. It will pop right off and the rivet stubs will come out with it. Takes about 15 minutes a 2 blades to remove one this way.

I cringe every time I hear someone taking half a day to get one of those things out.

70short · 11-11-2004, 01:59 PM

TX I like your method! The crossmmber is not going back on anything. OK so I guess I can't use my 4-speed crossmember

UMMM SAWS-ALL CUTTING TORCH !!!!!!!!!!!!!!! It seems to me that the holes are predrilled for the AUTO crossmember back (AFT) from the 4-speed holes??? generic. Thanks everyone anymore input would be greatly appreciated!!!!

Gary

Tx Firefighter · 11-11-2004, 02:11 PM

Yes, the holes will be there to meet you when you get ready. Get the proper 67-72 automatic crossmember and (8) 3/8 bolts and nuts.

mrein3 · 11-11-2004, 02:44 PM

Quote:

Originally Posted by Tx Firefighter

Quick Tx Firefighter Easy Method (TM) of removing the manual crossmember with the cab still on. Using Sawz-all, cut the center of the crossmember out to where there are just 4 wings left riveted to the frame. Now, slice the rivet heads off with the sawz-all. You can sneak the saw blade on top of the frame, between the frame and cab and nip the heads right off. Now hit each wing with a sledge hammer. It will pop right off and the rivet stubs will come out with it. Takes about 15 minutes a 2 blades to remove one this way.

I cringe every time I hear someone taking half a day to get one of those things out.

When I swapped my manual 4x4 to a th350 4x4 I spent 5 minutes with the blue wrench blowing out the rivets that held the center part on.

I cringe every time I hear someone taking 15 minutes to get one of those things out.

Jusk kidding of course about the 15 minute crack. However it did take about 5 minutes to blow them out.

70short · 11-11-2004, 04:25 PM

I still have to get the AUTO crossmember out in good shape. No air compressor where that truck is located.

Did I mention that I bought the whole truck for $300. The only thing I do not get is the 396 BIG BLOCK. Fire damage in the eng bay. Blistered fenders and hood " so what". Straight 3/4 ton AIR cab. 4 core RAD. I am stripping this truck. OH and the interior is clean, the bench seat is nicer than the one in my truck now.

Gary

Tx Firefighter · 11-11-2004, 06:00 PM

Getting the crossmember out of an auto truck is easy, it just unbolts, no rivets.

11-10-2004, 03:57 PM	#1
70short Registered User Join Date: Sep 2003 Location: Boise ID Posts: 609	Th400 I want to install an Auto TH400 in place of my old truck 4-speed. I have A 69 donner truck for the swap. Do I need the crossmember out of the donner truck or will mine work? I looked at my crossmember and it looks like it will be A pain to drill the rivets (upper 4). There is not alot of room to drop bolts into the upper holes for the swap. Do I need to lift the CAB? I cant wait to finally get An "AUTO" in place of the "OLD TRUCK 4-SPEED" Any help would be greatly appreciated! THANK YOU!!!!!!!!!!! Gary __________________ "72" Red CORVETTE 4-speed 350 "70" Chevy Short Bed early stages of resto. Edel 600 cfm carb Weiand Stealth Intake HEI shorty Headers 4/2 Drop 295 50R 15 TOYO on 10 inch wide corvette rally rims at all 4 corners. "CHEVY RULES" Last edited by 70short; 11-10-2004 at 04:03 PM.

11-10-2004, 11:02 PM	#4
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	you shouldnt need to lift the cab to accomodate the turbo 400, the 4 speed cab has a higher hump then an automatic cab anyways. Swap the crossmembers, by a new tranny mount for the crossmember because chances are the old one is toast anyways. __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

11-11-2004, 08:37 AM	#5
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Quick Tx Firefighter Easy Method (TM) of removing the manual crossmember with the cab still on. Using Sawz-all, cut the center of the crossmember out to where there are just 4 wings left riveted to the frame. Now, slice the rivet heads off with the sawz-all. You can sneak the saw blade on top of the frame, between the frame and cab and nip the heads right off. Now hit each wing with a sledge hammer. It will pop right off and the rivet stubs will come out with it. Takes about 15 minutes a 2 blades to remove one this way. I cringe every time I hear someone taking half a day to get one of those things out. __________________ I'm on the Instagram- @Gearhead_Kevin

11-11-2004, 01:59 PM	#6
70short Registered User Join Date: Sep 2003 Location: Boise ID Posts: 609	Scrap It TX I like your method! The crossmmber is not going back on anything. OK so I guess I can't use my 4-speed crossmember UMMM SAWS-ALL CUTTING TORCH !!!!!!!!!!!!!!! It seems to me that the holes are predrilled for the AUTO crossmember back (AFT) from the 4-speed holes??? generic. Thanks everyone anymore input would be greatly appreciated!!!! Gary __________________ "72" Red CORVETTE 4-speed 350 "70" Chevy Short Bed early stages of resto. Edel 600 cfm carb Weiand Stealth Intake HEI shorty Headers 4/2 Drop 295 50R 15 TOYO on 10 inch wide corvette rally rims at all 4 corners. "CHEVY RULES"

11-11-2004, 02:11 PM	#7
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Yes, the holes will be there to meet you when you get ready. Get the proper 67-72 automatic crossmember and (8) 3/8 bolts and nuts. __________________ I'm on the Instagram- @Gearhead_Kevin

11-10-2004, 08:24 PM	#2
john@thepier Senior Member Join Date: Aug 2004 Location: Lake Geneva, WI 53147 Posts: 970	depending on the cross member you have it will more than likely need to be swapped out.my 3 on the tree cross member had to be removed and replaced with a auto cross member.grinding and nocking out the rivets required me to have to un bolt the front of the cab and jack it up a little in order to fit my grinder in there.and that was after the engine and front clip was removed.soon I will be slipping in my new 400-400 combo GOOD-LUCK

11-10-2004, 08:29 PM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	You will need the auto cross member. If your cab mounts are bad you may need to lift the cab slightly to install the bolts, but I have not had a problem installing the upper bolts.

11-11-2004, 04:25 PM	#9
70short Registered User Join Date: Sep 2003 Location: Boise ID Posts: 609	Wow I still have to get the AUTO crossmember out in good shape. No air compressor where that truck is located. Did I mention that I bought the whole truck for $300. The only thing I do not get is the 396 BIG BLOCK. Fire damage in the eng bay. Blistered fenders and hood " so what". Straight 3/4 ton AIR cab. 4 core RAD. I am stripping this truck. OH and the interior is clean, the bench seat is nicer than the one in my truck now. Gary __________________ "72" Red CORVETTE 4-speed 350 "70" Chevy Short Bed early stages of resto. Edel 600 cfm carb Weiand Stealth Intake HEI shorty Headers 4/2 Drop 295 50R 15 TOYO on 10 inch wide corvette rally rims at all 4 corners. "CHEVY RULES"

11-11-2004, 06:00 PM	#10
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Getting the crossmember out of an auto truck is easy, it just unbolts, no rivets. __________________ I'm on the Instagram- @Gearhead_Kevin



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