700r4

[67ChevyRedneck]

Rusbuilt you may want to check your speedometer/odometer, because your fuel mileage flat out isn't possible. The 87 camaro V8 your trans came out of was only rated at 15 city 23 highway. I know, because I owned one, and those numbers were pretty accurate for me, sometimes a hair less... it was a Camaro, I did have a little fun in it

I have a 700R, been running it for many years. 3.73 rear, 350 engine runs great, and my best tank ever was babying it down the interstate at 60mph I squeezed out 17mpg. If I kick it up to 70-75mph she'll get 15-16mpg. Still, it was a vast improvement over the 10-12mpg it normally got...

I know guys with overdrives in first gen mustangs that only get 20-22mpg on the interstate.

I'm not trying to be an ass, I just want the OP and anyone who finds this thread in the future to have realistic expectations.

[Already Gone]

I just bought a 1992 Chev Silverado 4x2 with a 350 and ( it says in the specs ) 700R4/4L60 trans. The truck is a write off because of a little rear bumper damage. I drove it home and it runs and shifts good. I bought it for the taillights and K&N fresh air system that I can transfer to my Burb. I was gonna sell the motor and trans but now I'm thinking I should put the 700r4 in my BB truck. I also picked up a 3:08 posi rear to replace my 3:73's and was gonna put that in too, but am I corrct in thinking the 700's work better with 3:42's and 3:73's ? My main objective is fuel economy. the best I ever got with my truck is 10mpg ( US gallon ) and 12 mpg ( Imperial/ Canadian gallon ). I'd be extatic if I could get 16/17 Mpg from a US gallon.
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[67ChevyRedneck]

Originally Posted by Already Gone

I just bought a 1992 Chev Silverado 4x2 with a 350 and ( it says in the specs ) 700R4/4L60 trans. The truck is a write off because of a little rear bumper damage. I drove it home and it runs and shifts good. I bought it for the taillights and K&N fresh air system that I can transfer to my Burb. I was gonna sell the motor and trans but now I'm thinking I should put the 700r4 in my BB truck. I also picked up a 3:08 posi rear to replace my 3:73's and was gonna put that in too, but am I corrct in thinking the 700's work better with 3:42's and 3:73's ? My main objective is fuel economy. the best I ever got with my truck is 10mpg ( US gallon ) and 12 mpg ( Imperial/ Canadian gallon ). I'd be extatic if I could get 16/17 Mpg from a US gallon.
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Yes, you are. I have a 3.73, it's GREAT. Especially with the low 1st gear of the 700R, it makes launches fun! The 3.42 is the best choice for overall economy. Quite a few on this forum have complained that the 700R with a 3.07 is just too tall for the OD on the interstate causing more downshifting and not being within the correct powerband for a 350.

[clinebarger]

'82-mid '84 are 27 spline small shaft 700R4's.
Late '84 to '86 are 30 spline 700R4's.
'87-'93 4L60's have a auxiliary valve body (Forward accumulator).

[Jurassic-1]

I have a 700r4 in a 1972 CST Blazer. It has a lockup converter. I also purchased a Bowtie overdrive throttle adapter for the Quadrajet. (not yet installed) I currantly lock up the converter via a headlight dimmer switch mounted next to the steering column on the floor connected through a small red lamp under the dash by the e-brake handle. It works fine but it is manual so you need to remember to unlock it when slowing. I will have to check into the B+M kit listed in this post. I did not get any better mileage but it is driveable at high speeds on long trips.

[Already Gone]

Originally Posted by clinebarger

'82-mid '84 are 27 spline small shaft 700R4's.
Late '84 to '86 are 30 spline 700R4's.
'87-'93 4L60's have a auxiliary valve body (Forward accumulator).

2 Questions... Do the 87/93 700's have the 30 spline shaft as well as the auxiliary valve body, and what does the auxiliary valve body ( forward accumulator ) do?
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[clinebarger]

Originally Posted by Already Gone

2 Questions... Do the 87/93 700's have the 30 spline shaft as well as the auxiliary valve body, and what does the auxiliary valve body ( forward accumulator ) do?
Posted via Mobile Device

The 87-93 4L60's have a 30 spline input & an auxiliary valve body.

The Auxiliary valve body houses the Forward Clutch Accumulator.
GM added the forward clutch accumulator in order to give a much nicer (smoother) engagement when placing the shift lever into drive, This accumulator cushions the apply of the forward clutches.


In the earlier models......Some vehicles would bark the tires when dropped into gear and/or they would chew the splines off of the forward clutches over a period of time. This was REALLY a problem on TBI vehicles with the really high idle during cold starts & people not allowing the engine to idle down.

Adding the accumulator fixed that issue......But created another one, People have a habit of not allowing the forwards to completely "latch" up before giving it gas.....Causing the forward clutches to eventually burn up.

[Already Gone]

Originally Posted by clinebarger

The 87-93 4L60's have a 30 spline input & an auxiliary valve body.

The Auxiliary valve body houses the Forward Clutch Accumulator.
GM added the forward clutch accumulator in order to give a much nicer (smoother) engagement when placing the shift lever into drive, This accumulator cushions the apply of the forward clutches.


In the earlier models......Some vehicles would bark the tires when dropped into gear and/or they would chew the splines off of the forward clutches over a period of time. This was REALLY a problem on TBI vehicles with the really high idle during cold starts & people not allowing the engine to idle down.

Adding the accumulator fixed that issue......But created another one, People have a habit of not allowing the forwards to completely "latch" up before giving it gas.....Causing the forward clutches to eventually burn up.

Thank you.. I appreciate the info.
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[Rusbuilt]

Originally Posted by 67ChevyRedneck

Rusbuilt you may want to check your speedometer/odometer, because your fuel mileage flat out isn't possible. The 87 camaro V8 your trans came out of was only rated at 15 city 23 highway. I know, because I owned one, and those numbers were pretty accurate for me, sometimes a hair less... it was a Camaro, I did have a little fun in it

I have a 700R, been running it for many years. 3.73 rear, 350 engine runs great, and my best tank ever was babying it down the interstate at 60mph I squeezed out 17mpg. If I kick it up to 70-75mph she'll get 15-16mpg. Still, it was a vast improvement over the 10-12mpg it normally got...

I know guys with overdrives in first gen mustangs that only get 20-22mpg on the interstate.

I'm not trying to be an ass, I just want the OP and anyone who finds this thread in the future to have realistic expectations.

Oh I understand where your coming from! No offense taken... However I have been keeping an eye on it every time I drive it and I've been checking the milage based on the drive I make to the same place. I know how many miles it is and I've been filling the tank every trip just to be sure I have plenty of gas with the finicky gauge and I've put the same amount each time. So I know its consistent, and I promise you its between 22-25 mpg. I do need to check my rear end though because after reading a bit more I'm not sure I have a 3.07 gear. That was just what I was told when I bought it.