Turbo 400 - Good, Bad, and Ugly - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gene_ensor · 08-20-2009, 04:44 PM

Is there a good, better, or best turbo 400 transmission for our trucks? Are there certain years with a better case? Should we be using a short 4", or a long 9" shaft transmission? Are there any benefits to one over the other? Can anyone recommend an upgrade kit for a junkyard transmission? Thanks.

69swb 2wd
mods to hook, including migrating weight to back end
650-950 hp at crank without and with NO2
some weight reduction

clinebarger · 08-20-2009, 05:06 PM

I think the the long tailshafts are TH375s with the same spline count as a
TH350. go with the short. most have a bolt on yoke

Rodms · 08-21-2009, 12:04 AM

Its most in the tranny man,learn to build one its fun and its something you will never forget!Best of luck.I have long tails

KQQL IT · 08-30-2009, 03:04 PM

You can also look for one out of a motorhome better case straight cut planetarys(SP) will accept short tail shaft with a slipyoke

68 C-10 KID · 08-30-2009, 10:04 PM

650-950 hp at crank. That's a wide range.
Where are these numbers coming from?
A junk yard rebuild is not going to handle this type of power for very long.
What rpm are you launching @?

gene_ensor · 09-03-2009, 09:19 AM

Quote:

Originally Posted by KQQL IT

You can also look for one out of a motorhome better case straight cut planetarys(SP) will accept short tail shaft with a slipyoke

We are finally gaining some traction here! I would like to take this thread up a notch or two!

What do you guys recommend for turbo 400 rebuild kits. This company sounds like it has potential.

http://www.monstertransmission.com/

Kick butt music too!

shortbed70 · 09-03-2009, 07:48 PM

th 400's are cake to rebuild all you need is a small press and a couple seal installers. I would look for one with HD on the case and preferably out of a 2500 truck. Go for a good name brand kit like B&M,or hughes. Also make sure you get one with steeles cause you will prolly need them.

Marv D · 09-04-2009, 11:13 AM

Myself, I'd call Tony at Hughes, tell him what your dyno sheet says, tell him what you have (as in core TH400) and he will put together a 'care package' full of all the parts and pieces you need to build it to Hughes spec. I POUNDED on a Protree brake 400 hughes built for my Nova for 7 years without a hint of a problem. When your doing somewhere between 5-20 transbrake launches a month, on a prepped track, 10-12 months a year in a 3000 pound car, behind 660HP, on 14" slicks... you expect things to break eventually. Well they did,, the driveshaft, U-joints, the 4-link, the richmond gears, the strange axles, sheared all the lugs off once,, everything broke but the trans.

It's not all just about rebuilding with a quality stock component rebuild, it's abut knowhing what components your going to stress and replacing them with more durable items. That's where guys like Tony earn their bacon. Get a list of your combination, dyno sheet and give thm a call.you might find you can buy a new bulletproof Hughes TH400 for not that much more than you can accumilate the parts and buiuld yourself. Or Tony will get you a shopping last together and let you do it yourself.

gene_ensor · 09-15-2009, 11:40 PM

08-20-2009, 04:44 PM	#1
gene_ensor Registered User Join Date: Oct 2005 Location: Rapid City South Dakota Posts: 39	Turbo 400 - Good, Bad, and Ugly Is there a good, better, or best turbo 400 transmission for our trucks? Are there certain years with a better case? Should we be using a short 4", or a long 9" shaft transmission? Are there any benefits to one over the other? Can anyone recommend an upgrade kit for a junkyard transmission? Thanks. 69swb 2wd mods to hook, including migrating weight to back end 650-950 hp at crank without and with NO2 some weight reduction

08-20-2009, 05:06 PM	#2
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Turbo 400 - Good, Bad, and Ugly I think the the long tailshafts are TH375s with the same spline count as a TH350. go with the short. most have a bolt on yoke

08-21-2009, 12:04 AM	#3
Rodms Registered User Join Date: Jul 2008 Location: Olive Branch,Mississippi Posts: 347	Re: Turbo 400 - Good, Bad, and Ugly Its most in the tranny man,learn to build one its fun and its something you will never forget!Best of luck.I have long tails __________________ Built chevy tuff!

08-30-2009, 03:04 PM	#4
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,257	Re: Turbo 400 - Good, Bad, and Ugly You can also look for one out of a motorhome better case straight cut planetarys(SP) will accept short tail shaft with a slipyoke __________________ " That didnt make it any newer " " Dont antique the equipment "

08-30-2009, 10:04 PM	#5
68 C-10 KID Mean Green Join Date: Sep 2007 Location: Portland, OR Posts: 522	Re: Turbo 400 - Good, Bad, and Ugly 650-950 hp at crank. That's a wide range. Where are these numbers coming from? A junk yard rebuild is not going to handle this type of power for very long. What rpm are you launching @?

09-03-2009, 07:48 PM	#7
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	Re: Turbo 400 - Good, Bad, and Ugly th 400's are cake to rebuild all you need is a small press and a couple seal installers. I would look for one with HD on the case and preferably out of a 2500 truck. Go for a good name brand kit like B&M,or hughes. Also make sure you get one with steeles cause you will prolly need them. __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274

09-04-2009, 11:13 AM	#8
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: Turbo 400 - Good, Bad, and Ugly Myself, I'd call Tony at Hughes, tell him what your dyno sheet says, tell him what you have (as in core TH400) and he will put together a 'care package' full of all the parts and pieces you need to build it to Hughes spec. I POUNDED on a Protree brake 400 hughes built for my Nova for 7 years without a hint of a problem. When your doing somewhere between 5-20 transbrake launches a month, on a prepped track, 10-12 months a year in a 3000 pound car, behind 660HP, on 14" slicks... you expect things to break eventually. Well they did,, the driveshaft, U-joints, the 4-link, the richmond gears, the strange axles, sheared all the lugs off once,, everything broke but the trans. It's not all just about rebuilding with a quality stock component rebuild, it's abut knowhing what components your going to stress and replacing them with more durable items. That's where guys like Tony earn their bacon. Get a list of your combination, dyno sheet and give thm a call.you might find you can buy a new bulletproof Hughes TH400 for not that much more than you can accumilate the parts and buiuld yourself. Or Tony will get you a shopping last together and let you do it yourself. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

09-15-2009, 11:40 PM	#9
gene_ensor Registered User Join Date: Oct 2005 Location: Rapid City South Dakota Posts: 39	Re: Turbo 400 - Good, Bad, and Ugly Here is some research...... decent stall for the street? http://www.hotrodders.com/forum/dece...ight=turbo+400 THM 400 rebuild ... http://www.digitalcorvettes.com/foru...d.php?t=109572 GM turbo400/475 trans http://www.hotrodders.com/forum/gm-t...ans-93088.html How do I rebuild and hot up t400 transmissions? http://www.hotrodders.com/forum/how-...ight=turbo+400 How to Work with and Modify the Turbo Hydra-Matic 400 Transmission By Ron Sessions http://books.google.com/books?id=JJI...age&q=&f=false TH400 Build Tips with Pics http://www.hotrodders.com/forum/th40...cs-145318.html TH400 build-pictures http://www.turbobuick.com/forums/tra...-pictures.html TH 400 Tail Shaft Change http://www.hotrodders.com/forum/th-4...ight=turbo+400 th 400 transbrake??? or valve body http://www.hotrodders.com/forum/th-4...ight=turbo+400 turbo 400 - strength - recommended upgrades? http://www.hotrodders.com/forum/turb...t=turbo+400+91 Turbo 400 pump converter feed restriction http://www.turbobuick.com/forums/tra...striction.html Turbo 475 check balls http://www.hotrodders.com/forum/turb...ight=turbo+400 Enjoy! Last edited by gene_ensor; 09-15-2009 at 11:41 PM.

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