New Auto Tranny - The 1947 - Present Chevrolet & GMC Truck Message Board Network

VanceH · 04-25-2009, 07:26 AM

Hey i have got my old motor and 4speed out. Just wondering if anyone knows if i will have to resize my drive shaft for the new auto tranny?? I dont have it yet but looking at a TH400. Also do i need to remove the old 4speed crossmember?

Thanks
Vance

PanelDeland · 04-25-2009, 07:36 AM

Vance, you need to give a bit more info on what you have, what you're going to and what you're using.Differences in motor mounts,their location and other factors can cause different challenges.It may be best to install the driveline than measure and have your shaft shortened or a custom one built.Or you may find that a factory one works fine.There are just too many variables without more info.

VanceH · 04-25-2009, 07:41 AM

I am taking out a factory 283 with 4 speed...Thanks to the boy it now needs replaced!! and replacing it with a crate 350 and a TH 400. The 400 is a rebuild and i dont actually have it yet. I just pulled the front clip and removed the old 283 and tranny. I ordered a new cross member from a forum member for the new tranny. I just dont know if i should remove the old cross member??

Longhorn Man · 04-25-2009, 01:07 PM

If you had the cross member that bolted to the bellhousing, then yes, they'll need to come out, and you'll need a crossmember for an automatic tranny that supports it at the rear of the tranny.
Plan on driveshaft mods. If we are wrong, then it's "extra money"... if there is such a thing.

VanceH · 04-25-2009, 02:05 PM

it was actually bolted to the tranny itself two bolts. I have the new crossmember that i bought from a forum member?? DO you drill the rivets? Figured id have to change the length of the driveshaft.

jbristo67 · 04-25-2009, 02:09 PM

I knocked mine out with an air chisel. I am runing a turbo 350 I had an M22 and a 1 piece drive shaft. Drive shaft works with my 350. I think the 400 is longer though isnt it

BossHogg69 · 04-25-2009, 02:14 PM

just put a 5 speed where a Turbo 400 once lived. Cut the heads of the rivets and knocked them out. You can air chisel the heads off, torch them off, drill them out, whatever. I had to move the crossmember back and shorten the driveshaft. The Tremec I put in uses a Ford style Spicer yoke, so that had to be changed too.

04-25-2009, 07:26 AM	#1
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	New Auto Tranny Hey i have got my old motor and 4speed out. Just wondering if anyone knows if i will have to resize my drive shaft for the new auto tranny?? I dont have it yet but looking at a TH400. Also do i need to remove the old 4speed crossmember? Thanks Vance

04-25-2009, 07:36 AM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: New Auto Tranny Vance, you need to give a bit more info on what you have, what you're going to and what you're using.Differences in motor mounts,their location and other factors can cause different challenges.It may be best to install the driveline than measure and have your shaft shortened or a custom one built.Or you may find that a factory one works fine.There are just too many variables without more info. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

04-25-2009, 07:41 AM	#3
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Auto Tranny I am taking out a factory 283 with 4 speed...Thanks to the boy it now needs replaced!! and replacing it with a crate 350 and a TH 400. The 400 is a rebuild and i dont actually have it yet. I just pulled the front clip and removed the old 283 and tranny. I ordered a new cross member from a forum member for the new tranny. I just dont know if i should remove the old cross member??

04-25-2009, 01:07 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: New Auto Tranny If you had the cross member that bolted to the bellhousing, then yes, they'll need to come out, and you'll need a crossmember for an automatic tranny that supports it at the rear of the tranny. Plan on driveshaft mods. If we are wrong, then it's "extra money"... if there is such a thing.

04-25-2009, 02:05 PM	#5
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Auto Tranny it was actually bolted to the tranny itself two bolts. I have the new crossmember that i bought from a forum member?? DO you drill the rivets? Figured id have to change the length of the driveshaft.

04-25-2009, 02:09 PM	#6
jbristo67 resident oilfield trash Join Date: Jan 2009 Location: Lubbock TX Posts: 1,465	Re: New Auto Tranny I knocked mine out with an air chisel. I am runing a turbo 350 I had an M22 and a 1 piece drive shaft. Drive shaft works with my 350. I think the 400 is longer though isnt it __________________ 1967 SWB C10 396/400 factory air factory tach (sadly had to send to a new home) 1986 Honda 70 Fourtrax 1991 Chevrolet K5 blazer 2wd 1982 Mastercraft Pro Star 190 Stars and Stripes 2002 Chevrolet Tahoe 2011 Nissan Armada

04-25-2009, 02:14 PM	#7
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: New Auto Tranny just put a 5 speed where a Turbo 400 once lived. Cut the heads of the rivets and knocked them out. You can air chisel the heads off, torch them off, drill them out, whatever. I had to move the crossmember back and shorten the driveshaft. The Tremec I put in uses a Ford style Spicer yoke, so that had to be changed too. __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!



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