TH700R4 Shift Points

[minifridge1138]

Hello everyone,

I was wondering if anyone using the 700R4 automatic transmission should shift. It was the only transmission for 1982.

My shift points under normal acceleration are:
1>2 15 mph
2>3 30 mph
3>4 45 mph

I've read that if you don't have the TV cable set correctly, then you can have some serious problems. I know i adjusted mine once and i didn't shift 1>2 until i hit 45 mph. I am assuming that was set incorrectly.

thanks everyone

Remember to be careful out there. The life you save might be mine.

 

[kiwi vet]

BowTie Overdrives

Hey minifridge1138

Try this link

http://www.tvmadeez.com/article/index.php

Gives the low down on TV set up if you want to try.

Good Luck

Grant

 

[Autom8r]

Sounds like you are pretty close to mine that I hooked up in my '78 on normal acceleration. At WOT mine shifts around 4500 RPM, which I would like to stretch out to 5 grand. Big problem is it downshifts to 3rd at WOT, even at 110 MPH, which is scary. I understand there is a throttle sleeve that can be installed to prevent the screaming downshift.

Dave

 

[Peer81]

Big problem is it downshifts to 3rd at WOT, even at 110 MPH, which is scary. I understand there is a throttle sleeve that can be installed to prevent the screaming downshift.

A normal 700R4 will down shift from 4th back to 3rd when your at 50% WOT, when you have a corvette 700r4 (or any other stronger 700r4 with a stronger servo if I remember correctly) this will be at 75% WOT. So you can never drive your 700R4 at WOT in 4th.

Groeten Peter.

 

[Autom8r]

That sounds about right Peer81, 75% seems to be the magic number. But that's plain DUMB!! My '78 has a 3:55 gear and it screams it's guts out....

Have you heard anything about the throttle sleeve modification???

Dave

 

[minifridge1138]

Just out of curiousity, why do so many people not like the 700R? 3.06 first gear and a 0.7 overdrive sounds good to me.

 

[Autom8r]

Don't count me in on that.... I love the thing except for the WOT kickdown...

Dave

 

[Autom8r]

I just talked to a knowledgeable tech nerd at Sonnax in VT who is sending me info on the throttle sleeve to prevent or move the 4 - 3 downshift point.

Dave

 

[KANE]

Just out of curiousity, why do so many people not like the 700R? 3.06 first gear and a 0.7 overdrive sounds good to me.

Most of those folks are manual tranny people... they don't like any automatics.

I like the thunderbolt... so much I put one on my last C3.

 

[Evolution1980]

mini, in the pre-82's, the 700R4 is not a direct bolt-in replacement. It requires a custom transmission crossmember and also requires the driveshaft to be shortened. The only major difference between the 700R4 and the 200R4 is 1st gear AND that 200R4 is a direct bolt-in replacement. *No mods necessary.
I've heard some people don't like the 700R4 because the difference between 1st and 2nd gear is so vast that the engine drops way down in the RPM's during second gear...or something like that. I don't recall exactly. Personally, I like the 700R4 gearing. Others will disagree.

*As for the shift points, if my understanding is correct, while the TV cable can affect when it shifts, it's more controlled by the governor spring. My car shifts too late at WOT, so I need to go to a lighter spring (so I've been told).

*You can setup the 700R4 to run at WOT in OD. You simply need to wire up a manual override switch. I'm thinking about having it done on my setup. You just need to remember to flick it off when you are done or you'll stall your car when you come to a stop.


* I mark all these statements with asterisks because much of what I hear about I tend to forget over the winter months or when I'm not actively engaged in working on my car. Or, I'll just get the info mixed up with some other technical stuff.

Here's a little tidbit from our resident(?) vette guru c4c5Specialist that he gave me back when I was talking about TV cable adjustments. It would seem that all this "TV Made EZ" stuff has already been done by those that know. But for some reason, it never caught on. I guess not enough people know about it, and those that could promote the idea stand to lose money by not being able to sell their own custom setup... Anyways, here it is for setting up an auto-adjusting TV cable:

The TV cable part number is 25515598.
The bracket is discontinued from GM, but your application would be a 84-88 Caprice Classic, with a 5.0 engine with a 700r4 transmission, carbed.
This should let you get a used bracket from a junkyard.

 

[minifridge1138]

I really like the 700R in my 82.
it is good to know that it is not a direct fit. The shortened drive shaft means that IF i ever put in a different transmission, then I will also need to replace the drive shaft.

Thanks for the info,

 

[zachh]

There is a huge difference between the 200r and the 700r. Its like day and night. The 200r is made for lower performance- relaxed ratios, smoother shifts, lower stall.... The 700r is made for higher performance, harder shift, higher stall, lower ratios, etc. The TV (throttle valve) works by restricting the volume of fluid flowing through the valve body into the torque converter. It both controls the feel(hard, soft) of your shift and the rpm it shifts at. You can run a 700r at WOT in 4th, but you have to run a bypass switch to turn off the converter lock up. Also, the shift kit determines alot more what rpm it both shifts and downshifts at. Mine (BTO) has a custom shift lit, and if im at 70 in 4th(with converter lock) and I put the pedal to the florr, it will eaither go into 2nd, or 3rd depending on how aggressively I hit the pedal. If im at 50 with it just shifting into 4th, if I hit it , it goes down into 1st. Most people dont like the 700r just because when they came out in '82, it was the first 4- speed automatic, and they had alot of problems with overheating and burning up the frward sprag and the clutches. The 4L60 is the exact thing as the 700r4, just with a different name because the 700r had a somewhat bad reputation. The 4L60E, which came out in the early 90s has an electronic speedo gear and an electronic formn of TV.
Any Question Still?
Best Wishes
zachh

 

[Peer81]

The 4L60 is the exact thing as the 700r4, just with a different name because the 700r had a somewhat bad reputation.

I agree with the bad reputation thing but to my idea the 4L60 has some beter internals as the 700R4.

Groeten Peter.

 

[Autom8r]

I wired my 700R4 up to lock up the converter in 4th only + over 8" hg. vacuum + no brake. If I drop vacuum @ WOT or hit the brake the converter automatically unlocks. I can still apply a throttle tip-in at 100 MPH and it downshifts to 3rd.

Dave

 

[Sensei]

The 200r is made for lower performance- relaxed ratios, smoother shifts, lower stall.... The 700r is made for higher performance, harder shift, higher stall, lower ratios, etc.

\

Since when is a Buick Grand National "lower performance"? Both the 700 and 200 can be set up for any level of power / stall / ratio / hardness of shift. See Bow Tie Overdrive's site. God bless, Sensei

 

[zachh]

\

Since when is a Buick Grand National "lower performance"? Both the 700 and 200 can be set up for any level of power / stall / ratio / hardness of shift. See Bow Tie Overdrive's site. God bless, Sensei

I agree, the GN hauls ass, ive drivin my buddies... but if you were to look at the guts, y'ud see the difference. Both can be made equal in performance, but you can still feel a difference between the two.

 

[zachh]

I agree with the bad reputation thing but to my idea the 4L60 has some beter internals as the 700R4.

Groeten Peter.

uh.. I believe they have a bigger and stronger forward sprag and higher volume pump
zachh
they might have an extra clutch for both 1st and 2nd.... but im not sure... i cant remember