A4LD won't upshift at full throttle

[wood1]

http://www.explorerforum.com/forums/showthread.php?t=137972

Glacier's VB rebuild. (the clouds part, the bright sun shines through, doves take flight...)

 

[wood1]

http://www.explorerforum.com/forums/showthread.php?t=101571

Glacier's transmission rebuild thread, covers the governor nicely.

 

[North_Pole_Guy]

Question about bore 205 there is the first part behind the plug. What direction does it go into the bore? One side is open and the other closed, I think the open side goes out and will try to post a picture but not for sure. The picture in the astg manual does not clearly show it, and it is not apparent in the valve body rebuild thread. Ok so I can't seem to figure out how to post the picture. So does the open side go in or out on the plug?

 

[wood1]

In the build sheet that came with my TransGo shift kit, the governor boost valve open side is facing in with the large spring stuck into the valve. The smaller spring rides inside that larger spring, with the second and low boost valve on the end of that smaller spring.

Not sure if that is easy to follow or not, cup towards the center of the VB not pointing out.

 

[North_Pole_Guy]

Got it, just discovered that it would not fit the other way anyhow, spring would not allow the plug to fit the other way. I only have one spring on the large side, wonder if that got overlooked while putting the shift kit in?
Got about half the valves in tonight, calling it quits for the night, 13 hours at work a day only allows so much time for other projects at night.
I am just reassembling it all with the exception of the boost valve and will change the plugs out when I get the new ones in a few days hopefully.

 

[jd4242]

so back to post 35.i dont remember seeing this at all and cant find my papers anymore.does it say anything else about how to adjust it or where it should be able to kick down?

 

[North_Pole_Guy]

Post 3 covered it pretty well, the adjuster is on the firewall where the cable comes through on the engine side. Mine is like a grey round thing in the cable with a metal button type thing that you press and that allows you to pull the cable out. Then I think it says to with the explorer off press the throttle petal to the floor and that should be a good starting place for the adjustment.

 

[jd4242]

yea this is not my problem.i have adjusted it so many time im over it.its got to be a vacuum problem or psi problem.7/8 throttle it shifts just fine,goes to redline and shifts.full throttle no shift.the thing is i cant see the vacuum changing that much from 7/8 to full throttle.i guess i need to get an gauge and see what vacuum its pulling through the rpm rang.i just dont really understand how the a4ld decides when to shift??at what vacuum does it decide to shift at and how does it know that vacuum is at redline and not at 2 rpms?i wish it was computer controlled so i could just go in and tell it where and when i want it to shift.

 

[North_Pole_Guy]

The atsg manual has very detailed troubleshooting guide to help you determine where to start at.
Maybe a sticking governor? I am going to install my rebuilt valve body right now. I did the full upgrade on it and ordered a new governor weight along with new servo pistons and a few other odd parts to hopefully fix my shifting problem

 

[North_Pole_Guy]

Ok so I got my upgraded valvebody installed and it does shift through all gears and the torque convertor does lock up but I to have to run it up into the red to make it shift. Could it be the gov? I have a new weight for mine and will change it tomorrow and see what improvements it makes. It runs about 2500 rpm with the tq locked up at 55mpj now. This is getting frustrating now with all the work I have put into this project I can't be far from the finish line now....
Need to get this project done soon alot of other fall chores to complete.
Will update tomorrow after the new weight is installed.
The only other thing is that darn kickdown cable adjustment, fiddled with it a little tonight and am wondering if that could be the major or minor part of the problem?

 

[wood1]

Did you ever change the vacuum modulator? If not, I would do it along with the governor.

I am guessing that it shifts fine if you manually go through the gears? The governor stalk is the aluminum piece that will wear. It's easy to get at so not a big deal if you find the weight change doesn't help. I would try my best to smooth the stalk out with some fine paper.

 

[North_Pole_Guy]

No it does not shift manually either but does shift if redlined and you have to back off the gas a little.
I did put a new modulator in the came with the rebuild kit, should not need adjusted I wouldn't think?
Wonder if I should try the old modulator just for grins?
The only thing that I have not messed with though is the gov, I think I will go and take it out this morning and polish it up and install the new weight.
Is it possible that a sticky gov could cause shifting like that?
Maybe I should hook up a vac Gage and watch the vacuum also during a test drive.

 

[wood1]

Sticky governor could be doing it. How did you make out?

 

[North_Pole_Guy]

Well the piston in the governor was sticking, cleaned it up until it was free and put the larger upgraded weight on it and put it all back together. Test drive netted the same high rpm shifting but it does shift through all gears and the torque convertor even locks up and runs about 2300 or 2400 rpm's at 55mph, I think that is about right?

So could it be the new vacuum modulator? If it is and does need adjusted which way would I adjust it? Back the screw out or in and how much at a time?

Any other things to try?
Loosing hope now.

 

[wood1]

If you didn't mess up the modulator by losing the pin, or jamming goop in there while changing it, and you didn't play with the wheel yet, you might consider replacing the governor completely. I did what you did first, then had to go back in and change the piston and stalk and added the little weight return spring that came with one of the shift kits. I too polished it all up, but was forced to go back in and fix it properly. Again, make sure you have an A4LD modulator and not the C3 modulator as they are different.

 

[North_Pole_Guy]

Wood1 so did you have the same symptoms?
After polishing up all the governor parts it all looked great and moved freely.
So the modulator I got came with the rebuild kit maybe I should put the original one back in?

 

[North_Pole_Guy]

So the atsg manual says
• all upshifts harsh/delayed or no upshifts
1. Improper fluid level (not it)
2. Manual linkage --'misadjusted damaged. (maybe)
3. Governor sticking (not it)
4. Main control pressure too high (how)?
5. Valve body bolts -- loose/ too tight ( not it)
6. Valve body dirty/ sticking valves (not it)
7. Vacuum leak to diaphragm unit(not it)
8. Vacuum diaphragm bent, sticking, leaks ( maybe)

Going to change the modulator today and see what changes. Hooked up a vacuum pump to the line going to the modulator and it appeared to hold a vacuum.
Wonder if I can shift it going down the road with a vacuum pump hooked up and running into the cab?
I know I got the little piston and pin back in under the modulator. Maybe i got a bad modulator? Or incorrect one?

 

[North_Pole_Guy]

Just found a vacuum leak at the brake booster and sealed it up with some shoe goo, not sure if that could be effecting shifting but since that take is off the same tree as the vacuum modulator and it is all vacuum controlled I guess it can't hurt.
Took it for a test drive again and noticed that if you accelerate slowly it does seem to shift ok. You can see the shifts happening on a vacuum Gage that I hooked up and ran into the cab.
Or if you try to drive it like you were in the city it won't shift until you get it into the red.
Now I am starting to wonder if it is that new modulator, I am going to go pull it and see if I still have the old one to put back on.
Or maybe just adjust the one that is on there?

 

[North_Pole_Guy]

Ok bought a new modulator it is identical to the one that came in the rebuild kit. Got the old modulator and hooked it up to a vacuum hand pump and pumped it up, it seemed to work ok and compared how much vacuum it took to actuate it compared to the new one. The new one and the one from the rebuild kit took a fair amount more vacuum to compress. I adjusted the set screw in the reuildkit one until the amount of vacuum matched the old one then went for a test drive, NO improvement still shifts through all gears but you have to fool with the throttle to make it shift.

Not sure what to try, maybe when it cools down I will put the original one back on and try that.
I was watching the vacuum gage and it is when it hits around 22 or 23 in-hg and whatever speed it will shift. I am guessing it takes the surge in vacuum to move the modulator to allow the shift to take place. Maybe that piston that is behind the modulator pin is hanging up?

Another though I had was what about the speed sensor in the transfer case certainly that plays a part in when the transmission shifts? But if that was bad the spedo should be off I would guess? Wondering now about the piston behind the modulator....
Comments, suggestions?

 

[wood1]

I would change the rest of the governor completely.

First I rebuilt the VB. It worked better, but still wouldn't shift right.

I then replaced the weight and smoothed up the governor stalk. It seemed like it should work fine so I reinstalled it. Test drive and it still wouldn't shift right.

I then replaced the governor stalk and the piston and my problems disappeared.

I would change the governor stalk and the piston. It's not a lot more money, might as well try it.