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700r4 fun

wheels87k5

wheels87k5

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Looks like me and my 700r4 are going to go another round.

I had it rebuilt by a reputable transmission place in Wichita and it lasted just past the 12,000 mile warranty. So I got the DVD and a rebuild kit and tore into it.

The rebuild is not hard, and the DVD is very good in helping you along. But for some reason the 700r4 just wasn't happy.

It did great for about the first 5,000 miles then it started acting up. First, it wouldn't shift into OD until it reached a certain temperature, then would run fine. Now it bucks in and out of D and OD. I don't mean that it downshifts alot. It bucked like it couldn't make up its mind on where it wanted to ride. Drive or Overdrive. Either way, it needed to make up its mind. When it warmed up it would do it less but it was still there. In and out, in and out......Enough was enough.

So I'm going to rebuild it once more. I have the valve body apart and laying on a table nice and clean. Sometime today I'll tear the rest of the transmission apart and see if there is any visual evidence on what is going on.

If anyone wants pictures of any part of the 700r4, while it's apart, let me know.
 
Which dvd?

Any pics are good pics. Transmissions are still something that boggles my mind. Even after watching someone rebuild them.
 
I would start by looking at the sensors on the valve body before you rip it completely apart again namely item 346 347 and 348 in this pic
700r.jpg

700r.jpg
 
warrior454 said:
I would start by looking at the sensors on the valve body before you rip it completely apart again namely item 346 347 and 348 in this pic
View attachment 167908
Click to expand...

There is only 1 sensor on this valve body.

I haven't tore it apart yet, but I plan on starting in a few minutes unless someone can convince me not to. I talked to a tech at Pro Built Automatics and he suggested looking at the internals.

Tell me more.:popcorn:
 
Was hoping that would help since that is directly out of the GM cataloge and even looked up the 1985-86 Valve body and that shows the same sensors and the # 347 is a 4-3 pressure switch only other things I can think of would be not enough line pressure or a sticky shift valve but then I am a parts guy not a tech, I learned to rebuild them myself after our tranny tech put the kickdown spring in backwards and I couldn't get it to shift under 5k.
 
yeah, I would search through the valve body before even taking the trans out of the truck. Since you have all 4 gears, it's possible the pump and all the clutches are OK. Any scoring on the valves, broken springs or anything like that?

Oh, and find Greg Ducato. He may have seen this symptom before.
 
Deuling, the DVD I have is the one instructed by Paul Zank. 1995

Blue85, the transmission is already out and on my work bench. I had an oil seepage from the back of the motor and thought it was the rear seal that I replaced when I rebuilt the 700r4 the last time.

So I decided to pull everything out and found out it was the oil pan gasket. I got the Fel-pro gasket that is blue and very thick. You're not suppose to use any silicone. Just put it on dry. And now it's the 700r4s turn.

Here's the valves from the valve body


The valve body


And a broken plate gasket that I'm not sure if I tore it when removing the valve body or ? But it has to be replaced no matter how it happened.
 
How long does it stay in 4th gear? Obviously you can get the pressure to apply the servo, but maybe it bleeds off right after that? Have you looked at the servo yet?

Have you looked up the valve bores for scored walls?
 
Blue85 said:
How long does it stay in 4th gear? Obviously you can get the pressure to apply the servo, but maybe it bleeds off right after that? Have you looked at the servo yet?

Have you looked up the valve bores for scored walls?
Click to expand...

Just getting into it today. I took Friday and Monday off so I can work on this and get it back in the K5.

It would bounce between D and OD. Not hunt, but go in and out under load. I'd be on the highway and once up to speed, say 60 mph, it would keep going from OD to D. Back and forth. When the trans temp got up to about 150 it would mellow out and do it less while maintaining 60 mph. It didn't do it going 40 or so. Just up to highway speeds. I drained the fluid and it was a good color, not burnt or discolored. So I didn't suspect anything internal, just that after talking with an online tech it sounded like it couldn't hurt.

I would rather not if it is not necessary. And so far, I'm convinced not to tear it down. I'll start checking the valve body and valves to see if anything is out of the ordinary. And I'll check the servo and governor too. This could be interesting. Not sure if that broken gasket is what was causing it or not, but according to the online tech it was a possibility.

I HATE NOT BEING ABLE TO DRIVE HER. SHE'S........A DAMN GOOD RIDE!

Here's where the break can be seen right after the valve body was removed. I took the pictures as soon as I washed up.
 
Found two very tiny pebbles in the Accumulator valve bore, which I don't think was the real problem.



This might be the real problem. A bad stator shaft sealing ring.








They make a solid seal so I'll try those this time around.

Don't know how that happened but I'll replace both of them and reassemble the pump and try to get everything back together as soon as I can and see how it goes.
 
That ring is for the reverse input clutches. You described a sensation of going in and out of OD , that is a 900-1000 rpm variance between gears, quite substantial. It would make more sense that you are going in and out of lockup which is a 200-400RPM variance. The torn gasket is the second gear accumulator passage, wont have much to do with your problem. I would check the diaphragm in the pressure switch by blowing air into the threaded end and making sure the switch is holding. Does your harness still have a temperature switch in it? If so, you can wire around it to eliminate that as a possible problem. Check the governor shaft to be sure it isn't loose on the weight body, it is a press fit and if it isn't tight can cause 3-4 shift issues. I could write a book on things you can look for/improve when you have this apart. PM me for my phone number if you want to give me a holler and talk about it.
 
I agree with Greg Ducato on the issue being more lockup than shifting between 3rd and 4th. Finish tearing the trans down and make sure everything is right before you put it back in. In my experience if those seals are tore then the rest of the trans was probably scabbed as well.
The 4l60Es used solid seals on the pump but require some special tools to install and I don't think are worth the hassle since the scarf cut teflons work fine if they are installed and lubed properly.
 
Nothing useful to add. But man, these transmissions lasted 20+ years and 100k + miles. And modern upgraded parts a trans shop can't make it last the same?

:doah:

Good luck, and Greg write that book :D Maybe you'll be the go-to book for us, like Cliff Ruggles or Doug Roe for Quadrajets. :haha:
 
Thanks for the input......and yes, it was more of the lock up issue instead of dropping down in gear. I am learning more as I go.

The pressure switch was bad. It would not hold air and the center section would move out of its place. Have a new one installed.

Had the governor checked at the trans place and all is good.

Everything is now installed and once I have all fluids replaced, and fix a coolant leak at the thermostat, I'll set the tv cable and give it a test run.

Results pending.:popcorn:
 
bigblock72 said:
The 4l60Es used solid seals on the pump but require some special tools to install and I don't think are worth the hassle since the scarf cut teflons work fine if they are installed and lubed properly.
Click to expand...

I agree the cut teflons work fine. But if you have the solid ones I have found that if you use a small hose clamp to shrink the seal down. Same process as the special tool. Have used this technique on multiple transmissions and have had no problems with fitment and sealing. Just got to go slow and take your time and make sure its squared up. I have a video made and need to get it uploaded to youtube.
 
Now Greg may think this is hack, but I've switched to using electrical tape to resize seals. I've tried hose clamps with various materials underneath, zip ties, etc, but electrical tape works great on every size seal. Sure, it doesn't stick to oil, but only the first wrap is oily, subsequent passes are just tape sticking to tape. You pull it tight as you wrap and because the tape is stretchy it puts steady pressure on the seal 360 degrees, even as the seal shrinks into shape, with no marring or distortion.
 
Not a hack at all, whatever it takes to make it work. We have re-sizing sleeves that we use but for the guy who doesn't do this every day, there are many good ways to size rings and lip seals. I find on the input drum you can squeeze the rings together and carefully put the stator shaft down over it to size the four rings, one at a time, due to the taper of the inside diameter of the stator shaft. That is harder to do on the reverse input drum when using a solid ring as the bushing lip can interfere with the plan. You can actually cut a small taper into the base of the bushing and polish it up to make that job a bit easier.
 
Greg Ducato said:
That ring is for the reverse input clutches. You described a sensation of going in and out of OD , that is a 900-1000 rpm variance between gears, quite substantial. It would make more sense that you are going in and out of lockup which is a 200-400RPM variance. The torn gasket is the second gear accumulator passage, wont have much to do with your problem. I would check the diaphragm in the pressure switch by blowing air into the threaded end and making sure the switch is holding. Does your harness still have a temperature switch in it? If so, you can wire around it to eliminate that as a possible problem. Check the governor shaft to be sure it isn't loose on the weight body, it is a press fit and if it isn't tight can cause 3-4 shift issues. I could write a book on things you can look for/improve when you have this apart. PM me for my phone number if you want to give me a holler and talk about it.
Click to expand...

Sorry, Greg, but I didn't read the whole reply until it was too late. I was re-reading through the thread and saw the phone number available request. My loss. I will pm you next time I have it apart. I don't plan on anything going wrong with it, but if it does then I'll take it out and tear it down again. I really like the 700r4. Just can't seem to let it go. The OD is nice to have. So I'll keep at it until I get it built right. It's not hard to rebuild, just takes time.

And now for an update:

The transmission shifts great. It has a nice smooth shift to 2nd, good firm shift to 3rd, then another smooth shift to 4th. No more lock up problem, and shifts 100% better. I believe the bucking lock up issue was because of a bad pressure switch.

Also, I did not use the solid seals on the stator shaft. I was told the cut seals work great so that's what I used.

No oil pan leaks: Used the blue, one piece Fel-pro gasket.

No silicone on governor cap: Found an O-ring that works perfect. O'reillys Auto, isle with the grommets. Box of 10 and all different sizes.

Now, where's the snow? We can't have snow when it's 50-60 degrees outside. I know the NE has had more than enough and can send some to SE Kansas. I don't mind. :whistle:
 
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