G/V overdrive and 700R4 vs. TCI 6 speed auto - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Z POPPY · 10-17-2009, 02:12 AM

In need of some feedback. Going with a large built SBC and a built 700R4, 1964 c10. Thinking about going with a gearvendor O/D behind the 700R4. Claims of 10-15% MPH with gearvendors (about 2.25 mile more per gallon). G/V and 700R4 requires no shift programming and gets a .55 final trans ratio. Can handle what I am building. A friend suggested the new O/D from the general a 6L80E. It has a final trans ratio of .75 with 6 foward gears and TCI builds a monster version the generals. Adjustable shift points, full manual shifting with paddle shifter and would cost the same as a 700R4 and the G/V unit. It is just a matter of time before gas returns to $5 bucks a gallon. Other friends said keep it simple, built 700R4 and add G/V later if I still want it. Check out these pages and let me know what ya think.

http://www.gearvendors.com/hrgm4s.html

http://www.tciauto.com/Products/6x/

66GMC-Canuck · 10-17-2009, 05:35 AM

700R4 is a OD tranny. You can get them with a OD ratio of .7

fleetsidelarry · 10-17-2009, 08:39 AM

Z-poppy, are you going to race a little and also cruise, or just cruise? The 700-r is actually, in effect, a 5-speed. Mine is set up to manually lock up the converter whenever I want in OD (dropping the RPM another 300), so I have 1st, 2nd, 3rd, 4th(OD), and, at the flick of a switch, what amounts to another gear. The lockup can be set up to work off of vacuum, although mine isn't. With 3.07 gears I have interstate cruising around 2000 rpm.

I don't know if something with a wide power band like a V-8 benefits as much from a lot of gears as a 4 or 6 cylinder would.

(that paddle shifter sounds neat, though)

toms84ss · 10-17-2009, 12:08 PM

What rear gear are you planning on running with the double OD set up? You'll need something fairly steep to pull that kind of ratio. A t56 6 speed tranny will have about the same final drive and cost you less money to put together.

jwart · 10-18-2009, 10:48 PM

run 65 c10 327 with street strip cam? & 4.10 rear in it when i got it with
4,oomi on rebuild. ran for 3 yrs occasional driver as stock 3spd manual I put on the floor- till i dropped clutch at 90. rather than driving occasionally into Chicago rushhour traffic with another manual (which I love) I rebuild a th400. (kevlar bands & clutches & shift kit) have 9,000 mi. in less than a year. have done alot of highway miles aswell as some stop & go cities trips. i am extremely happy with auto & am saving my pennies for gearvender unit to go in next with 3.73 limited slip posi out of 89 burb. running 2300 converter. & hurst slap shifter so i can still play. this combo workes very well for me & anyone who's driven in it complements on its ride . have stepped down from 800 cfm rochester to 750-now 650 holley vac secondaries & getting 15 mpg from what was 10 mpg when i got it. happy enuf with it i leave my 02 4x4 chev 8.1L with allison trans just sits unless i need to tow something. hope u find good combo for ur truk. jw

10-17-2009, 02:12 AM	#1
Z POPPY Registered User Join Date: Feb 2009 Location: Bakersfield, CA Posts: 89	G/V overdrive and 700R4 vs. TCI 6 speed auto In need of some feedback. Going with a large built SBC and a built 700R4, 1964 c10. Thinking about going with a gearvendor O/D behind the 700R4. Claims of 10-15% MPH with gearvendors (about 2.25 mile more per gallon). G/V and 700R4 requires no shift programming and gets a .55 final trans ratio. Can handle what I am building. A friend suggested the new O/D from the general a 6L80E. It has a final trans ratio of .75 with 6 foward gears and TCI builds a monster version the generals. Adjustable shift points, full manual shifting with paddle shifter and would cost the same as a 700R4 and the G/V unit. It is just a matter of time before gas returns to $5 bucks a gallon. Other friends said keep it simple, built 700R4 and add G/V later if I still want it. Check out these pages and let me know what ya think. http://www.gearvendors.com/hrgm4s.html http://www.tciauto.com/Products/6x/

10-17-2009, 05:35 AM	#2
66GMC-Canuck Registered User Join Date: Sep 2009 Location: Edmonton, Alberta Canada Posts: 85	Re: G/V overdrive and 700R4 vs. TCI 6 speed auto 700R4 is a OD tranny. You can get them with a OD ratio of .7 __________________ 66 GMC 1500 Series LWB

10-17-2009, 08:39 AM	#3
fleetsidelarry Senior Car Nut Join Date: Jan 2008 Location: shellman bluff, GA Posts: 1,411	Re: G/V overdrive and 700R4 vs. TCI 6 speed auto Z-poppy, are you going to race a little and also cruise, or just cruise? The 700-r is actually, in effect, a 5-speed. Mine is set up to manually lock up the converter whenever I want in OD (dropping the RPM another 300), so I have 1st, 2nd, 3rd, 4th(OD), and, at the flick of a switch, what amounts to another gear. The lockup can be set up to work off of vacuum, although mine isn't. With 3.07 gears I have interstate cruising around 2000 rpm. I don't know if something with a wide power band like a V-8 benefits as much from a lot of gears as a 4 or 6 cylinder would. (that paddle shifter sounds neat, though) __________________ Larry Last edited by fleetsidelarry; 10-17-2009 at 08:44 AM.

10-17-2009, 12:08 PM	#4
toms84ss Registered User Join Date: Nov 2006 Location: Arizona Posts: 121	Re: G/V overdrive and 700R4 vs. TCI 6 speed auto What rear gear are you planning on running with the double OD set up? You'll need something fairly steep to pull that kind of ratio. A t56 6 speed tranny will have about the same final drive and cost you less money to put together.

10-18-2009, 10:48 PM	#5
jwart Registered User Join Date: Sep 2003 Location: n.e. IL border Posts: 208	Re: G/V overdrive and 700R4 vs. TCI 6 speed auto run 65 c10 327 with street strip cam? & 4.10 rear in it when i got it with 4,oomi on rebuild. ran for 3 yrs occasional driver as stock 3spd manual I put on the floor- till i dropped clutch at 90. rather than driving occasionally into Chicago rushhour traffic with another manual (which I love) I rebuild a th400. (kevlar bands & clutches & shift kit) have 9,000 mi. in less than a year. have done alot of highway miles aswell as some stop & go cities trips. i am extremely happy with auto & am saving my pennies for gearvender unit to go in next with 3.73 limited slip posi out of 89 burb. running 2300 converter. & hurst slap shifter so i can still play. this combo workes very well for me & anyone who's driven in it complements on its ride . have stepped down from 800 cfm rochester to 750-now 650 holley vac secondaries & getting 15 mpg from what was 10 mpg when i got it. happy enuf with it i leave my 02 4x4 chev 8.1L with allison trans just sits unless i need to tow something. hope u find good combo for ur truk. jw



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