700r4 won't shift

[82blazer]

The suburban's (Labrat) r4 has just been completely rebuilt by us. It received an Alto 3-4 kit, upgraded to 13 vane pump, all new clutches, steels, gaskets, corvette servos, new converter, new tv cable, beast sunshell gear,and a rebuilt reverse input drum.
It first had a pressure problem that turned out to be the pressure relief valve. That has been taken care of, but now the transmission will not upshift from first gear. So far we have: tried a different governor, checked the valve body gaskets, checked the 1-2 shift valve, the governor filter is clear, the 2-4 servo appears to be fine, the band is new and the pin is in place.
Any ideas are appreciated. So far the troubleshooting has taken 2 weeks.

[Robyn]

Was the VB all apart??

There may be an issue with the 1-2 shift valve

Robyn

[82blazer]

Yes, it was, but I believe it was put back right. I am using an ATSG manual for the 700R4. According to the book possible 1-2 shift valve (322) sticking. While double checking I also checked this it seemed free. This is also the first transmission I have ever done, so I am not sure of anything though we (my son and I) are learning (the hard way :rolleyes:).

[Robyn]

I hate to say it but unless you find something that jumps out at you you are going to have to carefully go through the VB again and make sure all, the valves are in the right way. There are several items that if reversed will not work.

Yes you can do this. Also be very certain all the check balls are in the proper palces. Make absolutely sure that the gaskets between the seperator plate and the VB and between the plate and the case all have the right holes in the right places.
If you have a hole in the plate that is cover by a gasket instead of having a hole where it should its game over.

Unfortunately at this point a diagnosis is tough. If the tranny had been working and then just quits it becomes easier to pinpoint.

You should also check the 2-4 band servo to make sure the feed passages are not blocked and also check to make sure the band is anchored properly.
The seals in the servo are another area to check.

Good luck and keep us posted

Robyn

[82blazer]

The valve body is all correct, the gaskets and plate are right, the check balls are in the right places, the servo seals are good, and the band is hooked up. How do you check the servo passages?

[Robyn]

I usually do it with air as I am assembling the tranny.

[Robyn]

have you checked to make sure the TV cable and system are working correctly. If the TV is set way to high it will shift waaaaaaaaaaaaaaaaaay late if at all??

[82blazer]

We replaced the cable with an after market one. With the pan off i pulled the pawl up to where it is just about to touch and set it there. (TV pushed in to touching the spring.) Is there a way to air check the passages in the truck? The ATSG does not seem to show the locations with the valve body off. Also tried it with the cable unhooked, didn't matter. One other note every one keeps asking me will it manual upshift and it doesn't.

[82blazer]

We went through the valve body again. Everything was right. When we installed the valve body, a slight imperfection around a bolt hole in the spacer plate was noticed. It was flattened out, and the transmission was put back together.
The truck did shift during the test drive. It was only taken as high as 3rd. After about a dozen shifts we lost it again. Is there any way this could be the governor? About the only thing left seems to be a brand new diesel governor.

[Robyn]

You certainly could have governor issues.
If its OTL the beast wont shift at all no matter what you do.
The correct way to set the TV cable is to adjust the slider unit all the way back to the firewall and then mash the throttle. The cable will ratchet out to the proper length. The test is on a very light throttle 1-2 shift you mash it just as it shifts into 2 and it should drop back to 1 right now if it does not you need more Tthrottle pressure.

[JohnC]

I knew a guy who had similar symptoms. Turns out he had not flushed the cooler and each time he "fixed" it at ran OK for a few minutes, until the debris from the original failure got into the valve body...

[82blazer]

I've read your other post about the TV cable the problem with the one I bought is that it is universal with about 4" of extra cable and a little brass stop. I'm afraid I just don't understand the govener and can't seem to find anything to explain it to me. The one in the truck seems free and looks good enough to be new. When I pulled the valve body to recheck everything it was clean as when I had put it in. While I don't think it is a dirty valve body I know better than to say it isn't. Can anybody point me toward an explaination of the gov.? Thanks for all the help so far. Hope to get this thing on the road soon.:)

[Robyn]

Get a pressure gauge that will read from 0-300 PSI and hook it up to the main line port on the tranny. You will need enough high pressure hose to get it up by the drivers window.
Do some pressure checks and then lets go from there.

Idle in N, D,3,2,1.
Run the rig up to 1-2 shift speed and lets see what the pressures are doing.

[82blazer]

Pressures at idle are as follows:
Park 135-140 psi
Reverse 200 psi (this did drop to about 150-160 after a little driving)
Neutral 135-140 psi
Drive 135-140 psi
Third 135-140 psi
Second 100-110 psi (Isn't the boost valve suppose to be active here and First?)
First 100-110 psi
While driving to get up to 1-2 shift speed 60-180 psi I think. The needle on the gage at times was moving so fast that it appeared to be going completely around and only stoped bouncing when I let up off the pedal. I ran all the way up to 20 mph and it didn't offer to shift. Hope this tells you something. Thanks again

[wthif]

Needle should not bounce and the pressures look wrong.

Mine:
1st & 2nd : 200PSI cold 150PSI hot (hot jumps right back to 200 with slight throtle input)
3rd & 4th : starts at 75PSI (cold or hot) and goes up with more throtle.
N & P : 75PSI not sure about change with throtle
R : 150-200PSI can't remember

What really worries me is your 1st & 2nd pressures.

Now it is time for Robyn to jump in and tell you what to do.

[AKMark]

Double check your TV cable connection at the trans. My K-5's 700R4 had a new cable installed by a local tranny shop that was supposed to be one of the best around this neck of the woods (done by previous owner). When I would drive it I had to rev my 350 to almost 5000 RPM to get it out of first. If I would've had this with my 6.2L I don't think it ever would have shifted. The previous owner didn't think it was a problem but I did so I got a huge discount when I bought it and took it home to troubleshoot. They had not even connected the cable at the trans side is what I found during the testing.

My pressures were about the same as yours when I did the pressure test prior to checking the cable. After connecting the cable properly the pressures came down to normal and shifts were great.

So that's where I'd start, pull the 5/16's (if I remember correctly) bolt that holds the TV cable and see if the cable falls away completely. If it does, fix it. If it doesn't, it still sounds like you may have a TV system issues like a gasket on the plunger is bad or something.

That's where I'd start anyway. I only learned about this about four months ago when I went through almost the exact same thing.

[82blazer]

The cable is connected though not sure about adjustment. While the pan was off for the valve body check we also checked and readjusted the TV cable. I just don't understand why the gage bounces while driving. the trouble shooting in the ATSG don't get into pressures much. The pressure in 1st and 2nd are steady when it is not moving but is being given approx. half throttle still about 110 psi. Just don't know what to look at next.:confused:

[82blazer]

I replaced the cable with an OEM unit then mashed the pedal and it did nothing. Took it for a drive and it is still the same.:mad: This can not be the only one out there that has done this.:confused:

[82blazer]

I think I've figured it out. :) It was the T.V. Ex. check ball. Everyone said to remove this. (it is the largest one) I have since found out that in the trans. before '87 this is a no no anything after it is a yes yes. Now that it is put back the trans seems to be behaving. Now I need plates to run on the road to be sure. But I'm hoping and thanks to all for your advice. Frank:D