[USNChief]

Well, it's time for the switch from the TH350 to the 700r4.

I currently have 385 hp and 427 ft pounds of torque. (Not where I want it. A little higher.)

I'm guessing that the 700r4 has generations. I want one that requires no computer. I have a 1980 and do not want any computers on this car. Can someone tell me what generation I'm looking for?

 

[[email protected]]

long time no see Chief.. welcome back.. the 700r4 was from 82-93 I believe.. the first generation has a smaller input shaft,weak trans, stay away from it, try to get a late 80 s version .. none of the 700r4 s use computers, the 4L60 E is the computer control version of it ... you will need to beef it up to handle the added power, the stock model is only good for about 350ftlbs of torque or simply get one already built for performance applications.. Monster , TCI, PATC, even Jegs and Summit have them now..when you are ready to begin install, get with me or Toobroke, we can walk you thru the mods you will need to do ....believe me, YOU WILL LOVE THE 700r4..

 

[USNChief]

long time no see Chief.. welcome back.. the 700r4 was from 82-93 I believe.. the first generation has a smaller input shaft,weak trans, stay away from it, try to get a late 80 s version .. none of the 700r4 s use computers, the 4L60 E is the computer control version of it ... you will need to beef it up to handle the added power, the stock model is only good for about 350ftlbs of torque or simply get one already built for performance applications.. Monster , TCI, PATC, even Jegs and Summit have them now..when you are ready to begin install, get with me or Toobroke, we can walk you thru the mods you will need to do ....believe me, YOU WILL LOVE THE 700r4..

Hey Fish! I burned up my TH350:smilielol5:. I had planned on switching to the 700r4. Looks like it's a little sooner than later. A friend has convinced me that I can rebuild the 700r4 myself. So that is what I will attempt to do. Now the search.

 

[[email protected]]

I think we now have a half dozen members that have swapped to 700r4s...they are plentiful in salvage yards.. you need to improve the clutchpaks and use a Fairbanks Servo ,a good lock-up converter w/mild stall ... toobroke can give you more specifics on internals.. get a repair manual ,and you ll need a few tools .. there are some necessary modifications, to make the swap,.driveshaft, crossmember, shifter detent ,e-brake pulley ,carb bracket ,etc and proper adjustment of the Throttle Valve Cable ..I recomend an auxillary cooler too for reliability..... we can fill you in when you are ready..good luck

 

[USNChief]

I was just asked if I need a "long tail or short tail" tranney. Any ideas? :noidea:

 

[[email protected]]

either can work, the short tail means less modifiction to crossmember but they are pretty hard to find ...make sure its not an early model with smaller input shaft

 

[USNChief]

either can work, the short tail means less modifiction to crossmember but they are pretty hard to find ...make sure its not an early model with smaller input shaft

Thanks fish! Sounds good. I'll let you all know what I end up with.

 

[toobroketoretire]

TH700R4 Transmissions

Well, it's time for the switch from the TH350 to the 700r4.

I currently have 385 hp and 427 ft pounds of torque. (Not where I want it. A little higher.)

I'm guessing that the 700r4 has generations. I want one that requires no computer. I have a 1980 and do not want any computers on this car. Can someone tell me what generation I'm looking for?

The 1982 thru 1983 TH700R4's have a 27-spline input shaft whereas the 1984 and later have the slightly larger 30 spline input shaft. Either can be beefed up to handle your engine but the 1984 and up would be the better choice. In late 1986 an auxiliary valve body was added to smooth the shifting. The nice thing is the later parts can usually be used in the earlier cases with the exception of the 1982 cases.

They are very easy to overhaul with ordinary metric hand tools and the two spring compressors that you will need are easily fabricated. All you need is a Haynes G.M. transmission overhaul manual and about a day of your time.

If you decide to overhaul yours e-mail me at [email protected] and I'll clue you in on the little details that the Haynes manual overlooked. I have overhauled all of my automatic transmissions since I was a kid and there's nothing to them.

 

[USNChief]

The 1982 thru 1983 TH700R4's have a 27-spline input shaft whereas the 1984 and later have the slightly larger 30 spline input shaft. Either can be beefed up to handle your engine but the 1984 and up would be the better choice. In late 1986 an auxiliary valve body was added to smooth the shifting. The nice thing is the later parts can usually be used in the earlier cases with the exception of the 1982 cases.

They are very easy to overhaul with ordinary metric hand tools and the two spring compressors that you will need are easily fabricated. All you need is a Haynes G.M. transmission overhaul manual and about a day of your time.

If you decide to overhaul yours e-mail me at [email protected] and I'll clue you in on the little details that the Haynes manual overlooked. I have overhauled all of my automatic transmissions since I was a kid and there's nothing to them.

Thanks toobroke. Honestly, I don't feel like building a transmission. But if you say I can do it a day, then I guess I'm game. My friend says it will save me about 1k if I do this myself. I am still on the look for the transmission. Once I am ready to start, I'll give you folks a hollar. :rant:

 

[toobroketoretire]

Overhauling A TH700R4

Thanks toobroke. Honestly, I don't feel like building a transmission. But if you say I can do it a day, then I guess I'm game. My friend says it will save me about 1k if I do this myself. I am still on the look for the transmission. Once I am ready to start, I'll give you folks a hollar. :rant:

Chief, you'll need two tools to compress spring packs and they're easily made using pieces of steel that you can buy from most every lumberyard. When you're ready contact me and I'll send you pictures of the tools I made and also include their dimensions. I also made a 12" X 12" plate for my floor jack to make the removal/installation easy. Then with the aid of a Haynes manual (about $25) you can easily rebuild any G.M. transmission.

Automatic transmissions may look real complicated but they're not when you follow the step-by-step procedures in the well-illustrated Haynes manual. The manual gives you an individual picture of every part being installed from start to finish so there's almost no chance for error. The Haynes manual is very thorough but there are a few things that I can tell you to do to ensure a quality overhaul.

To handle more than 300 ft/lbs of torque there are a few parts that need to be purchased such as 9 disc 3-4 clutch pack (about $45) and Fairbanks servos (about $180). Plus a wider carbon fiber band ($25) and a new band drum (about $50) along with a "Beast" sun shell (about $50). Figure about $750 to $800 worth of parts to get a transmission capable of handling 500 ft/lbs of torque. Most transmission supply houses stock the parts you'll need for considerably less than internet prices.

 

[USNChief]

Thanks for the info. I think I may have found a transmission. My next question is how do I tell the difference between a long tail and short tail transmission?

 

[[email protected]]

the long 700r4 measures 30 3/4 inches overall ,front bolt flange to rear of housing....is there a driveshaft shop near you? you will need to have yours shortened by either 2 - 3 inches depending ..costs about $80-$100, good time to pop in new U-joints if yours are old , Spicer or Neapco are strongest.. you ll need a TV Cable and carb Mounting bracket..[ Monster Trans. has them] your TH 350 stuff won t work ..your old shifter/ cable will work fine ,you need the shift lever on the 700r4..... to be able to access all 4 gears manually, you ll need to convert the shifter detent.[ Shiftworks.com makes a nice conversion kit,complete with new indicator PRND321]. if you don t care about that, you can leave as is, but you cannot manually put it in 1st gear and your 3rd position will be 4th OD...lets us know how we can help, Toobroke and I have done these , so we can steer you in right directions

 

[toobroketoretire]

As I never saw any point in being able to lock mine in 1st gear nor any point in having mine read "4" instead of "D" I didn't bother altering my shifter or buying the shorter lever for the transmission.

Chief, you'll need to add a pressure switch to the 4th gear servo pressure tap to control the torque converter lockup. I have read the TH700R4's made after 1987 didn't have the pressure taps so if you get a 1988 or later you'll have to use a pressure switch in the valve body. When the time comes contact me and I'll tell you how to do it depending on the year you get.

 

[vetteoz]

My next question is how do I tell the difference between a long tail and short tail transmission?

Only difference in T700 tail shaft housings in the style.
Most are bare ,some have provision for a reg GM trans mount, F-Body has extra mounting holes for the torque arm
and the C4 Vette version is 1' shorter with a special mount for the C Beam used in those cars

C4 on left

F-Body

 

[vetteoz]

I have read the TH700R4's made after 1987 didn't have the pressure taps so if you get a 1988 or later you'll have to use a pressure switch in the valve body.

http://www.thirdgen.org/techboard/carburetors/492891-tcc-control.html

 

[[email protected]]

good info.. there are, as in the atricle , multiple ways of achieving dersired results depending on your own set-up and driving habits.. mine is set up with 4th gear pressure switch, eliminating the ECM s involvement as it is not used with my strokers operation, and tho I did not make use of a vacuum defeat for high load , I do have a manual lock-out switch , as my big cam does not like lockup at low rpm

 

[USNChief]

Ah hah! I got the transmission today. It came off a 1986 Suburban. Now I'm getting a little excited.

 

[[email protected]]

:woowoo:

 

[USNChief]

Here it is. I just seem to be having trouble finding the manual for this.

 

[USNChief]

Thanks to tobroke. The manual is ordered and on the way.