PDA

View Full Version : More 700R4 Woes



4x4Dreamer
12-29-2005, 08:39
I am having more trouble with my 700R4. Here's the skinny. I rebuilt it, with the help of my friend. When we finished, we took it to a shop and had a guy check it out. he had to fix a few things and life seemed good. Find.
So I put it back in the truck and now here are the issues I'm having.

1-2 shift happens at about 9 mph.
2-3 shift happens at about 40 mph.

I've only forced it a few times. I've adjusted the TV cable 6 ways from Sunday, it only moves the 1 - 2 shift by 1-2 MPH. On a shops recommendation, I put the Tcase in neutral, the trans in drive and floored it hoping to break something loose, no dice. I've made sure the TV cable was hooked up, but I'm stuck. Anybody have any ideas?

The governor is new...pretty much everything is new. Heavy duty servos, used a TCI rebuild kit.

Any help is greatly appreciated.

john8662
12-29-2005, 08:56
Here is the test:

Start up, get the truck warm, go around the block and let the trans go through all the gears.

Then come back, find a place in the road where there is no traffic. Stop the truck in the road. Now, very gently accelerate, wait until you feel the transmission make it's first shift event into 2nd gear, then punch the petal to the floor. The transmission should immediatly shift back down to 1st gear and rev the engine up to the governor and shift.

If you don't get a shift back down, then your TV cable is not adjusted correctly.

My rule of thumb on getting the TV cable "close" is to adjust the cable with the air cleaner off until you can manually rotate the injection pump throttle and upon rotating the pump throttle you see the TV cable being pulled. You'll have to adjust it to where you get it to this point manually. Obviously, if you have the cable too tight, the cable will move when you rotate the pump throttle, you want the point just before this.

So, start with it loose, then work a click or two at a time until you get there.

The manual will suggest that you press the TV cable adjustment holder button, and manually push the TV cable adjuster into it's holder all the way. Then take the throttle and run it fully open, forcing the adjuster to ratchet to where it needs to be. I find that it doesn't get close enough doing this.

I can't remember at what Speeds the gears all shift at, I'll take a drive and take note. I'm "listening" to the engine RPM to determing if it's shifting at the right times.

A correctly adjusted transmission will also vary when it shifts depending on the amount of throttle being applied. More throttle = delayed shift, etc. Light throttle, early shift (better economy).

P.S. I like your signature quote, I hope to prove it wrong by the end of the summer :D

4x4Dreamer
12-29-2005, 09:16
That's good info, thank you. (I'm proud of that quote, I came up with it myself :D )

My concern is something is wrong in the valve body, and i don't want to mess with that fiasco again.

My understanding is that the TV cable will only effect the shift points by a few MPH, not enough to overcome the difference between a 40 MPH shift and a 25 MPH shift. Could this be a problem with governor gear? It's new and the guy assured me it was right for my application. I think the only diff in governors is the springs...right? But wouldn't that effect ALL shifts?

I really don't want to kill my tranny testing it too much if you can imagine.

Should there be a break in period, in which things seat and break loose from the assembly goop or what?

My wife really wants the truck on the road again since it's our family hauler.

Thanks again.

john8662
12-29-2005, 10:55
I got back from lunch, I took note of the shifting characteristics of my 82 truck's 700.

I get the First shift under a very moderate acceleration at ~10 MPH

~25 MPH I get the 2nd to 3rd shift and locking Torque Converter (feels like two shifts)
~40 MPH I get the 3rd to 4th (OD) shift, can't feel the TC lock though (it was already locked)

Of course, a heavier foot gives me a delayed shift.

So, I think your shift points, based on your speed are correct.

You probably had the previous trans build shifting late from 1st to 2nd, which is something wrong with the trans and or cable adjustment (probably more wrong with the trans than anything).

Does your transmissions' shifting respond to where you have your foot?

Adjust the TV cable close, as stated above, then do the testing. I'm aware of no "break in" period for transmissions. I always think of a transmission as ready to go to work, as long as it's adjusted correctly.

Governers in the transmission are a mystery to me currently, I've only had one run in with them, in that a trans I had built by a local shop had the wrong gov in it. It caused the transmission to NOT shift under WOT into the next gear, because the engine couldn't achieve enough RPM to satisfy the Gov. So my engine would rev and sit bumping the gov in the IP until I let my foot out of the petal enough for it to shift anyways. So, I couldn't do any full throttle runs.

4x4Dreamer
12-29-2005, 11:22
see, you're getting your 3-4 shift where I'm getting my 2-3 shift...which as any of us 6.2 nuts knows, running a 6.2 to 40 in 2nd gear has it screaming.

From what i've found, the 1-2 shift should be happening closer to 15 mph, but I think 10 is acceptable.

I just miss stinking of diesel when I get home...and my stupid carburetor is givng me trouble...i HATE carburetors. I much prefer mechanical injector pumps.

john8662
12-29-2005, 11:57
oops, I didn't catch that!

You're 2-3 shift IS really late. I don't think this is a TV thing now, usually if out of adjustment, 2nd to third will be really early and not shift back down.

Still, adjust the TV, and see where you are at, it's still a possibility.

I dislike messing with carb's, I like the ability of getting the Diesel started in the morning, and once started, it keeps running, no dying because it feels like it.

4x4Dreamer
12-29-2005, 12:10
My plan is to drop the pan and see if somehow the TV linkage is bound up. My friend hooked it up while I was hooking stuff up to the Tcase.
After that...I'll probably curl up into a ball and shudder. :confused:

arveetek
12-29-2005, 14:16
I'm leaning towards a wrong governor. I bought a Suburban one time with a freshly rebuilt 700. It wouldn't shift right, and when it did, it shifted WAY too late. Turns out the tranny shop installed a governor for a 700 that went behind a V6 gasser. The diesel governor had much heavier weights, and changed the shift points considerably.

You're correct in that TV adjustment will only do so much. The governor has a lot to do with shift points as well.

Casey