Used Transmission - The 1947 - Present Chevrolet & GMC Truck Message Board Network

one9six9 · 06-16-2007, 07:55 AM

I need a transmission. I'm trying to get by as inexpensive as possible since I don't really know how long I will have a three speed set up, but I don't have the money free to upgrade to the 700r yet.
I have a turbo350 with my 250 I6. I found someone that has a turbo400 that was pulled out of a 69 Chevy Chevelle two years ago. He says that it had about 5000 miles on it when it was pulled. It also has the stock torque converter. I don't know what size engine was in the car, but he thinks that I will have to get a new torque converter because the flywheels are not the same. If this is correct and the flywheels are not the same can I just swap flywheels, or are the bolt holes different from one torque converter to another?
Oh yea, is there anything that I need to look out for on a used transmission, or is there anything that can be checked being that the transmission isn't installed in a car?

Thanks,
Keith

cdowns · 06-16-2007, 08:35 AM

you know you'll need to shorten your driveshaft for a 400tranny

killer71 · 06-16-2007, 08:42 AM

Imho if i were you financially i would save my money until ready for the 700r. wouldn't waste my time/money on modified shaft, my time, possibly problems with turbo 400. But that's just me!

one9six9 · 06-16-2007, 01:42 PM

I didn't know that I would have to cut the driveshaft. I thought the 400was just a stronger version of the 350. I don't have the funds for the 700 right now, and the transmission I have is not driveable.

Would it be a nightmare to rebuild it myself?

Keith

mnunn454 · 06-16-2007, 03:25 PM

Rebuilding either would/can be a nightmare if you aren't well equipped and very patient and careful with the details.

Saving the money for a 700R is nice, but if you need a tranny now, assuming the 350 and 400 have the same length tailshafts, the used TH400 should be an easy replacement for the 350.

You will need a larger front slip yoke for the driveshaft (TH400's output is larger than the TH350's) and probably a special U-joint, but you shouldn't have to cut the driveshaft until you go with the longer TH700.

I don't think you'll need a new flexplate. The TH400 converter should bolt up right where the TH350's did onto your existing flexplate. I think you could even use your TH350 converter and flywheel if you wanted to because TH350and Th400 converters are usually interchangable.

70GMCer · 06-16-2007, 03:45 PM

**Palf70Step** · 06-16-2007, 06:58 PM

another thing to remember is the T400 equipped truck came with the high tunnel. I am not sure if they would squeeze int there of a low hump cab. Sure it would, but it would be tight for cooling. To go from a T350 to T400 requires a lot of changes and the money spent on those changes may not be worth it.

You maybe able to find another T350 (V8 or 6) or 2004R overdrive (same length as the T350 in trucks) to swap yours out with.

The T400 will bolt in, but the other stuff you need, drive shaft mods, new yoke might not make it worth the money. We have some pick & pulls that normally have decent prices on used tranny's and they normallly tand behind them too.

Good luck on your find.

earl87gta · 06-16-2007, 07:05 PM

I would think you can find a used 700r4 for not much more then that 400 would be you can probly by a old camarro or firebird with a 700r4 in it for almost nothing and sell what s left of the car.

stllookn · 06-16-2007, 08:17 PM

None of my small block trucks with the TH400 have high humps...I think that was just the big block trucks.

Longhorn Man · 06-16-2007, 09:12 PM

that's right, TH400 did not dictate a high hump at all... only on 1/2 ton GMC trucks with the v-6.
A Th400 converter will not bolt onto a flex plate that was made for a Th350.
I don't know about swapping flex plates from an inline to a small block.
Persoanlly, I would look elsewhere for a Th350.
If you trust this cat, and the tranny is dirt cheap, I'd buy it just for trading material... some one with a TH350 may trade you even up.

06-16-2007, 07:55 AM	#1
one9six9 Junior Member Join Date: May 2007 Location: Milton, FL Posts: 64	Used Transmission I need a transmission. I'm trying to get by as inexpensive as possible since I don't really know how long I will have a three speed set up, but I don't have the money free to upgrade to the 700r yet. I have a turbo350 with my 250 I6. I found someone that has a turbo400 that was pulled out of a 69 Chevy Chevelle two years ago. He says that it had about 5000 miles on it when it was pulled. It also has the stock torque converter. I don't know what size engine was in the car, but he thinks that I will have to get a new torque converter because the flywheels are not the same. If this is correct and the flywheels are not the same can I just swap flywheels, or are the bolt holes different from one torque converter to another? Oh yea, is there anything that I need to look out for on a used transmission, or is there anything that can be checked being that the transmission isn't installed in a car? Thanks, Keith

06-16-2007, 08:35 AM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Used Transmission you know you'll need to shorten your driveshaft for a 400tranny __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

06-16-2007, 08:42 AM	#3
killer71 Registered User Join Date: May 2006 Location: at work Posts: 2,552	Re: Used Transmission Imho if i were you financially i would save my money until ready for the 700r. wouldn't waste my time/money on modified shaft, my time, possibly problems with turbo 400. But that's just me! __________________ R.I.P. Killer 71 10/26/07

06-16-2007, 01:42 PM	#4
one9six9 Junior Member Join Date: May 2007 Location: Milton, FL Posts: 64	Re: Used Transmission I didn't know that I would have to cut the driveshaft. I thought the 400was just a stronger version of the 350. I don't have the funds for the 700 right now, and the transmission I have is not driveable. Would it be a nightmare to rebuild it myself? Keith

06-16-2007, 03:25 PM	#5
mnunn454 Registered User Join Date: Dec 2006 Location: Rhode Island Posts: 602	Re: Used Transmission Rebuilding either would/can be a nightmare if you aren't well equipped and very patient and careful with the details. Saving the money for a 700R is nice, but if you need a tranny now, assuming the 350 and 400 have the same length tailshafts, the used TH400 should be an easy replacement for the 350. You will need a larger front slip yoke for the driveshaft (TH400's output is larger than the TH350's) and probably a special U-joint, but you shouldn't have to cut the driveshaft until you go with the longer TH700. I don't think you'll need a new flexplate. The TH400 converter should bolt up right where the TH350's did onto your existing flexplate. I think you could even use your TH350 converter and flywheel if you wanted to because TH350and Th400 converters are usually interchangable. __________________ 69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe

06-16-2007, 03:45 PM	#6
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Used Transmission __________________ 1997 GMC Sierra Ext 1965 Mustang

06-16-2007, 06:58 PM	#7
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,083	Re: Used Transmission another thing to remember is the T400 equipped truck came with the high tunnel. I am not sure if they would squeeze int there of a low hump cab. Sure it would, but it would be tight for cooling. To go from a T350 to T400 requires a lot of changes and the money spent on those changes may not be worth it. You maybe able to find another T350 (V8 or 6) or 2004R overdrive (same length as the T350 in trucks) to swap yours out with. The T400 will bolt in, but the other stuff you need, drive shaft mods, new yoke might not make it worth the money. We have some pick & pulls that normally have decent prices on used tranny's and they normallly tand behind them too. Good luck on your find. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

06-16-2007, 07:05 PM	#8
earl87gta Senior Member Join Date: Dec 2003 Location: Kingsport TN Posts: 4,641	Re: Used Transmission I would think you can find a used 700r4 for not much more then that 400 would be you can probly by a old camarro or firebird with a 700r4 in it for almost nothing and sell what s left of the car. __________________ Earl 68 2500 4x4 GMC Burb

06-16-2007, 08:17 PM	#9
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: Used Transmission None of my small block trucks with the TH400 have high humps...I think that was just the big block trucks. __________________ '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)

06-16-2007, 09:12 PM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Used Transmission that's right, TH400 did not dictate a high hump at all... only on 1/2 ton GMC trucks with the v-6. A Th400 converter will not bolt onto a flex plate that was made for a Th350. I don't know about swapping flex plates from an inline to a small block. Persoanlly, I would look elsewhere for a Th350. If you trust this cat, and the tranny is dirt cheap, I'd buy it just for trading material... some one with a TH350 may trade you even up.



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