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700R-4 version 3.0

Preliminary results are good, as proven by Swamper tracks. Was delayed due to another foot of snow today, but that's just how Spring is.

Short term plan is to re-install torque rods, front driveshaft, etc. and store in barn until *real* spring comes (we just passed fake spring #3, with a couple more feet predicted this weekend.), then test transmission for real. It's amazing how many gallons of ATF are required for full tranny rebuild and full T-case rebuild.

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Blue85 said:
Preliminary results are good, as proven by Swamper tracks. Was delayed due to another foot of snow today, but that's just how Spring is.

Short term plan is to re-install torque rods, front driveshaft, etc. and store in barn until *real* spring comes (we just passed fake spring #3, with a couple more feet predicted this weekend.), then test transmission for real. It's amazing how many gallons of ATF are required for full tranny rebuild and full T-case rebuild.

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Good to have positive results!
:saweet:
 
K5 is put away in the back of the barn, awaiting better weather. The only things missing are the skid plate and the torque rods. It's been really weird having all of the fluids filled and no spots of oil on the floor. I've been keeping cardboard under it for years, maybe decades.
 
I've driven this a few times, aiming to get the fluid level right. These new pale oils don't help. It drives good most of the time and uses 4 gears, but sometimes shifts weird. The TV cable is not auto-adjusting as described, but I'm able to tell at some level when it's actually doing something and when it's bottoming out.

Needs more attention, but so fun to drive vs. lay under.
 
Blue85 said:
I've driven this a few times, aiming to get the fluid level right. These new pale oils don't help. It drives good most of the time and uses 4 gears, but sometimes shifts weird. The TV cable is not auto-adjusting as described, but I'm able to tell at some level when it's actually doing something and when it's bottoming out.

Needs more attention, but so fun to drive vs. lay under.
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That's great.
Hopefully soon I will be getting to my 700r4 rebuild.
In the meantime I am trying to get my 98 going, started with an exhaust leak and found burnt wiring and I am trying to get it fixed.
 
On the way to work and back today in it, I realized that the issue was the proportion and consistency of where it thought my throttle was at. Sure, there could be differences between Quadrajet and TPI, but both are shown in the B&M manual and when I measure distances and angles, it all matches the book (those are all factory parts for Firebird/Camaro and AFAIK the TV valve and linkage were the same for 700s in those cars).

Of course, there's no replacement for a good visual inspection, as you know. I asked myself "why is there a spring on the TV cable?" I remembered some issue decades back of needing the cable a little shorter than the "retract and floor it" method provided, but it was limiting the throttle to 80% or something (oh, the humanity). An online vendor provided the spring as a fix, everything worked good and I drove for many years. I pulled it off tonight, reset the TV cable by the book and bam! Runs good. Downshift to 1st when I slow down, grabs gears at reasonable times and feels firm when there's any throttle. What's gone is the needlessly harsh 1-2 when I'm creeping along (i.e. trails).
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I'm going to re-check line pressure and fluid level and then start planning some adventures.
 
There's a lot I don't know about transmissions and now I've gone down a rabbit hole with line pressure. What I've realized it that line pressure isn't TV pressure. I recorded some numbers below, but they're not at full TV. They're at whatever throttle yields 1000RPM. I tried pulling the TV cable separate from the throttle and it just acts weird, like getting stuck at 120psi until the engine is restarted.

Driving on the road it's varying from like 80-140 psi, but the shift points vary way more than that. So it's probably fine. It drives good. There are RPMs where the gauge needle is flipping around violently. Is that bad or normal or is it just the cheap gauge?20260605_192318.jpg
 
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At idle, any movement of the TV cable changes line pressure, so that indicates the adjustment is right. But line pressure is also affected by what gear you're in. 2 or 1 is higher than 3 or D and reverse is the highest. So that composite signal doesn't really tell you directly what TV is doing.

You can see that the pressure regulator valve runs from "TV Feed" (I can't tell you what's different between that and "TV", other than there appears to be a restriction), Low range (present when 2 or 1 is selected) and Reverse signals.

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I run the Sonnex spring on my TV cable, un altered Q jet 4MV throttle arm. I could not get wot with cable adjusted to procedure.
I do have a very firm 1-2 up shift. Thinking maybe if I move the sheath 1 tooth relaxed, leave the spring. Have to experiment.
I had a pressure gauge installed for years, but my mind didn't retain the numbers.
I do recall Bow Tie Overdrives requiring full table of pressures for warranty when I first installed in 2009. Might have that noted down somewhere.
This current 700r4 is 3rd and best one ever, done by The Toy Shop, not Bow Tie Overdrives.
 
Ultimately I may not be happy until I can adjust the shift tables. I find it ironic that some prefer the "simplicity" of a hydraulic brain transmission.
 
You can take the governor out and grind on the weights to increase the shift points. There were two sets of weights in the TH400 if I recall, not sure how they do it in the 700 for the 4th gear shift but I'm pretty sure it still had a governor. I suppose you could add tack welds to decrease the shift point. I have done the grinding with the TH400 I had in the truck, it does work. Just do it in 4LO as shift happen quicker, I did it first in high range and then when I shifted to low range it would hit the rev limiter too quick before it shifted. This will move the entire shift curve though as you do that at WOT, if you only want to move part throttle shifts I don't know how to do that, maybe TV cable adjustment or an adjustable vacuum modulator for a TH350 or TH400?

This is one of the main reasons I took the 700R4 out of my K5 and put in a 4L60E out of a 99 5.7L burb. Having done that before, I didn't want to do it again. It bolted right in and I had the controller wires just sitting there to hook up to the computer. I can change the pressure and shift points anywhere in the table for any gear or the lockup with a few button clicks. It's basically like EFI is for the engine, but for the trans.

Does mega squirt have a trans controller that works with your EFI?
 
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I have the Camaro governor, which is basically just the frame with no weight added. I haven't haven't tried it recently, but I pretty much always lifted to shift below the 1-2 WOT point.
 
Wouldn't a stock truck TBI governor be closer than the camaro unit with your engine? You didn't swap the cam or anything did you?
 
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