Th400 Or 700r4 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

eightbanger · 05-03-2008, 01:44 AM

Took my truck on it's first long journey the other day 4 hr round trip most of it on the freeway and she took it in her stride It's running a 454 mated to a TH400 which has been tweaked by the po (see sig) and all the while I was wishing I had a 4th gear...cause driving at a steady 75mph the engine was really reving high, had the radio up real loud just to hear it there was a lot more to go on the gas pedal but if I took it passed 80 mph they would have heard it in Scotland. My question is this, would swaping out the 3 speed auto TH400 for that 700R4 that everyone seems to be going for solve this? is my engine reving that high at speeds cause it needs a 4th gear. Then i'm thinking is there a down side to having a 4 speed? like losing the power that I have now just running around at lower speeds. Or is there a better trany out there that would give me the best of both worlds? any help or sugestions are appreciated.

Ol'Rover · 05-03-2008, 01:53 AM

TCI 700R4, They handle 454's nicley, my uncle has one in his 56 Bel-Air, bought a crate 454 and he said he's pushin out about 450+ horsepower. He had a TH400 onit befor, and when he changed over to the 700 he noticed a big difference, put more power to the ground quicker, and way better cruising he said.

**leddzepp** · 05-03-2008, 01:53 AM

I have 700r4 and love it. It actually has a very low 1st gear, so you have a great holeshot at traffic lights. If you are worried about losing any power at higher speeds, keep the overdrive off. I do not know about any other automatics in these trucks, but I do like the 700r4.

Rollie396 · 05-03-2008, 02:01 AM

You could check out a gear vendors overdrive unit?I don't know a whole lot about them,but a fella I know has one behind a real nasty 468/T400 combo and he loves it.

eightbanger · 05-03-2008, 02:12 AM

I'm not very mechanicly minded so when you guys talk about overdrive is that 4th gear or what? Leddzepp what do you mean when you say keep the overdrive off?. Rollie do you have any other info on that overdrive unit you mentioned?

haysonj · 05-03-2008, 02:16 AM

I have the gear vendors with a turbo 400 and I love it It's like having a six speed and really helps with the towing. the stock ones are good up to around 1200 HP but they are pricey I paid $3300 for mine.

Rollie396 · 05-03-2008, 02:22 AM

Here's their site...they are a little pricey,but I think it may be worth it.

http://www.gearvendors.com/custom.html

Ol'Rover · 05-03-2008, 02:26 AM

got a normal GM 700R4 in my 88, and it also has a realy nice low 1st gear, as said...great for getting the holeshot at stop lights lol

eightbanger · 05-03-2008, 02:26 AM

Thanks Rollie

Now I need to decide between the two, that may be down to price...and how easy are any of these options to fit? I mean is this a leave into the shop job or a DIY thing??

jayharrell · 05-03-2008, 02:50 AM

Do you have to have some control modual for the 700?? isn't it computer controlled?? *know nothing about the r4 other then its a 4 speed.

Ol'Rover · 05-03-2008, 03:11 AM

The 700R4 is all mechanical and hydraulic. You are thinking of the 4L60E the electronic version of the 700R4

haysonj · 05-03-2008, 03:12 AM

The 700R4 is not a good trans for a heavy truck especially if you are towing or racing. also they have to be set up exactly right or they won't last. The gear vendors is a direct bolt on and all you have to do is shorten the drive shaft. Only took me two hours to install and had my drive shaft back that afternoon and was on the road. Very simple

Rollie396 · 05-03-2008, 03:17 AM

haysonj,how was the electrical part of the install?Fairly simple?Looks like it may take a bit of getting used to using it?

eightbanger · 05-03-2008, 03:29 AM

Yeah its' a shame the copperhead video doesn't show more of the install especially the electrics, I had no idea about this gear vendors thing it really looks like the way to go pricey but a lot simpler on the install and to be fair Bowtie Overdrives do state that if you want that bit more then gear vendors or there own 4l80E is what you will need.

haysonj · 05-03-2008, 03:44 AM

The electronics are simple you just mount the controls and they plug in It has a speed sensor that goes in the speedo cable for the automatic operation. I have the B&M Mega shifter and they sold me the handle with the shift button like they did in copperhead. You can shift it off and on between gears so it acts like a six speed. I usually leave it on and it shifts by speed usually only three gears but if I hit a grade I turn it off and it drops to the normal 1 to 1 gear.

Vince M · 05-03-2008, 03:47 AM

The selection of the 700r4 is great if you have the right gear ratio in the rear end. It sounds like you have a 3.73:1 ratio which the 700r4 will work great with. You can even go to a 4.10:1 and it will work great. If you have a 3.08:1 the fourth gear will drop the enginge revs too low at freeway speeds.
With a lockup you can keep the transmission oil heat down and even gain a few hundred rpms of more overdrive.
With the right mounting the 700r4 will bolt right into the same location as the TH400. You want a tail section that has the mount on it. This gives you pan clearance with the crossmember and it will use the same tranny mount and crossmember as a Th400.
I put two 700r4's in now and with the right stuff it works great.
With a 3.73:1, a 700r4 and 30" diameter rear tires I was doing 1800 rpm at 70 mph in lockup. You won't need to turn the radio up anymore to drown out the motor.

05-03-2008, 01:44 AM	#1
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Th400 Or 700r4 Took my truck on it's first long journey the other day 4 hr round trip most of it on the freeway and she took it in her stride It's running a 454 mated to a TH400 which has been tweaked by the po (see sig) and all the while I was wishing I had a 4th gear...cause driving at a steady 75mph the engine was really reving high, had the radio up real loud just to hear it there was a lot more to go on the gas pedal but if I took it passed 80 mph they would have heard it in Scotland. My question is this, would swaping out the 3 speed auto TH400 for that 700R4 that everyone seems to be going for solve this? is my engine reving that high at speeds cause it needs a 4th gear. Then i'm thinking is there a down side to having a 4 speed? like losing the power that I have now just running around at lower speeds. Or is there a better trany out there that would give me the best of both worlds? any help or sugestions are appreciated. __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger

05-03-2008, 01:53 AM	#2
Ol'Rover Project: years too late. Join Date: Dec 2007 Location: Almonte,ON,Canada Posts: 550	Re: Th400 Or 700r4 TCI 700R4, They handle 454's nicley, my uncle has one in his 56 Bel-Air, bought a crate 454 and he said he's pushin out about 450+ horsepower. He had a TH400 onit befor, and when he changed over to the 700 he noticed a big difference, put more power to the ground quicker, and way better cruising he said. __________________ 1971 C10 Stepper LSX 5.3/4L60E 3.73 12bolt posi. Father Son Project. In Memory of Bruce C. Shorten. Rest easy Dad. Ill take it fryom here.

05-03-2008, 01:53 AM	#3
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,997	Re: Th400 Or 700r4 I have 700r4 and love it. It actually has a very low 1st gear, so you have a great holeshot at traffic lights. If you are worried about losing any power at higher speeds, keep the overdrive off. I do not know about any other automatics in these trucks, but I do like the 700r4.

05-03-2008, 02:01 AM	#4
Rollie396 someday it will be done! Join Date: Sep 2004 Location: Lloydminster,AB. Canada Posts: 1,620	Re: Th400 Or 700r4 You could check out a gear vendors overdrive unit?I don't know a whole lot about them,but a fella I know has one behind a real nasty 468/T400 combo and he loves it. __________________ '72 C-10 Proud owner of a million new and used pieces that used to be and will once again be(god willing) a testament to the term "they don't build em like that anymore. '80 LWB 2wd beater '67 GMC long fleet (cab donor) '66 long step (parked till it's turn comes around) '65 short step (parts truck that will donate it's bed and possibly frame to the '66) '06 Grand Prix wife's car (she hardly lets me touch it) my pics

05-03-2008, 02:12 AM	#5
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Re: Th400 Or 700r4 I'm not very mechanicly minded so when you guys talk about overdrive is that 4th gear or what? Leddzepp what do you mean when you say keep the overdrive off?. Rollie do you have any other info on that overdrive unit you mentioned? __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger

05-03-2008, 02:16 AM	#6
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: Th400 Or 700r4 I have the gear vendors with a turbo 400 and I love it It's like having a six speed and really helps with the towing. the stock ones are good up to around 1200 HP but they are pricey I paid $3300 for mine. __________________ 69 Chevy 4x4 383 Power

05-03-2008, 02:22 AM	#7
Rollie396 someday it will be done! Join Date: Sep 2004 Location: Lloydminster,AB. Canada Posts: 1,620	Re: Th400 Or 700r4 Here's their site...they are a little pricey,but I think it may be worth it. http://www.gearvendors.com/custom.html __________________ '72 C-10 Proud owner of a million new and used pieces that used to be and will once again be(god willing) a testament to the term "they don't build em like that anymore. '80 LWB 2wd beater '67 GMC long fleet (cab donor) '66 long step (parked till it's turn comes around) '65 short step (parts truck that will donate it's bed and possibly frame to the '66) '06 Grand Prix wife's car (she hardly lets me touch it) my pics

05-03-2008, 02:26 AM	#8
Ol'Rover Project: years too late. Join Date: Dec 2007 Location: Almonte,ON,Canada Posts: 550	Re: Th400 Or 700r4 got a normal GM 700R4 in my 88, and it also has a realy nice low 1st gear, as said...great for getting the holeshot at stop lights lol __________________ 1971 C10 Stepper LSX 5.3/4L60E 3.73 12bolt posi. Father Son Project. In Memory of Bruce C. Shorten. Rest easy Dad. Ill take it fryom here.

05-03-2008, 02:26 AM	#9
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Re: Th400 Or 700r4 Thanks Rollie Now I need to decide between the two, that may be down to price...and how easy are any of these options to fit? I mean is this a leave into the shop job or a DIY thing?? __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger Last edited by eightbanger; 05-03-2008 at 02:32 AM.

05-03-2008, 02:50 AM	#10
jayharrell Gettin By on Gettin By Join Date: Jan 2008 Location: Cedar Creek, Tx Posts: 1,033	Re: Th400 Or 700r4 Do you have to have some control modual for the 700?? isn't it computer controlled?? *know nothing about the r4 other then its a 4 speed. __________________ 69 CST10 LWB 455 Buick 00 S10 2.2 Vin5 76 GL1000 Naked 1bl VW carb "Adios to all the concrete; Gonna get me some dirt road back streets"

05-03-2008, 03:11 AM	#11
Ol'Rover Project: years too late. Join Date: Dec 2007 Location: Almonte,ON,Canada Posts: 550	Re: Th400 Or 700r4 The 700R4 is all mechanical and hydraulic. You are thinking of the 4L60E the electronic version of the 700R4 __________________ 1971 C10 Stepper LSX 5.3/4L60E 3.73 12bolt posi. Father Son Project. In Memory of Bruce C. Shorten. Rest easy Dad. Ill take it fryom here.

05-03-2008, 03:12 AM	#12
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: Th400 Or 700r4 The 700R4 is not a good trans for a heavy truck especially if you are towing or racing. also they have to be set up exactly right or they won't last. The gear vendors is a direct bolt on and all you have to do is shorten the drive shaft. Only took me two hours to install and had my drive shaft back that afternoon and was on the road. Very simple __________________ 69 Chevy 4x4 383 Power

05-03-2008, 03:17 AM	#13
Rollie396 someday it will be done! Join Date: Sep 2004 Location: Lloydminster,AB. Canada Posts: 1,620	Re: Th400 Or 700r4 haysonj,how was the electrical part of the install?Fairly simple?Looks like it may take a bit of getting used to using it? __________________ '72 C-10 Proud owner of a million new and used pieces that used to be and will once again be(god willing) a testament to the term "they don't build em like that anymore. '80 LWB 2wd beater '67 GMC long fleet (cab donor) '66 long step (parked till it's turn comes around) '65 short step (parts truck that will donate it's bed and possibly frame to the '66) '06 Grand Prix wife's car (she hardly lets me touch it) my pics

05-03-2008, 03:29 AM	#14
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Re: Th400 Or 700r4 Yeah its' a shame the copperhead video doesn't show more of the install especially the electrics, I had no idea about this gear vendors thing it really looks like the way to go pricey but a lot simpler on the install and to be fair Bowtie Overdrives do state that if you want that bit more then gear vendors or there own 4l80E is what you will need. __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger

05-03-2008, 03:44 AM	#15
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: Th400 Or 700r4 The electronics are simple you just mount the controls and they plug in It has a speed sensor that goes in the speedo cable for the automatic operation. I have the B&M Mega shifter and they sold me the handle with the shift button like they did in copperhead. You can shift it off and on between gears so it acts like a six speed. I usually leave it on and it shifts by speed usually only three gears but if I hit a grade I turn it off and it drops to the normal 1 to 1 gear. __________________ 69 Chevy 4x4 383 Power Last edited by haysonj; 05-03-2008 at 03:44 AM.



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05-03-2008, 03:47 AM	#16
Vince M Senior Member Join Date: Apr 2000 Location: Orlando, FL Posts: 1,076	Re: Th400 Or 700r4 The selection of the 700r4 is great if you have the right gear ratio in the rear end. It sounds like you have a 3.73:1 ratio which the 700r4 will work great with. You can even go to a 4.10:1 and it will work great. If you have a 3.08:1 the fourth gear will drop the enginge revs too low at freeway speeds. With a lockup you can keep the transmission oil heat down and even gain a few hundred rpms of more overdrive. With the right mounting the 700r4 will bolt right into the same location as the TH400. You want a tail section that has the mount on it. This gives you pan clearance with the crossmember and it will use the same tranny mount and crossmember as a Th400. I put two 700r4's in now and with the right stuff it works great. With a 3.73:1, a 700r4 and 30" diameter rear tires I was doing 1800 rpm at 70 mph in lockup. You won't need to turn the radio up anymore to drown out the motor. __________________ ............................................................ 68 Chevy CST SWB w/LS1, carb & 700r4. Golden Anniversary clone with a few improvements.

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