no reverse, very strange

[donaldthacker]

a few weeks ago I lost reverse. with glaciers help I found the problem to be the reverse modulator. I cleaned it up and put the superior kit, knowing that I needed to located a better valve body due to some damge I saw in the associate bore. well the tranie worked fine and I finally got a good used valve body. I went throught the new used one same as last time with the superior kit and ford upgrade, put it all back in and still no reverse. I checked all of the soleniods and they fell within the ohms listed in the diary. I still have forward gears but no reverse. one question I do have is when I pull the valve body what position should the reverse servo be? by this I mean up in the bore or down near the plate. I do not know if it means anything but was just curious.
I have checked and changed just about everything listing in the diary, even the dtr, so any advice?

 

[toypaseo]

When my parent's had the Explorer I have now, reverse went out on it for no obvious reason. Forward was fine. I had to push it out of the garage, and then follow my Dad to the nearest Ford garage.

Transfer case went out. Hopefully this is not your problem since it was not a cheap fix

 

[donaldthacker]

transfer case seems to work fine. I put the tranny back togther about 2 weeks ago everything worked fine. I knew I needed a new valve body housing, which I just got so I made the change.
The strange thing is that I had the ex on jack stands and had someone put it in reverse while running and you could actually see the drive shaft trying to move. I put it 4low and the shaft would move, but not move the truck. Also I could grap the shaft and hold it while turing. so it is not fully engaged

ideas?

 

[BrooklynBay]

Connect a pressure gauge onto it, and check how much pressure you have in reverse.

 

[pj8847]

When you say "pushed up" into the bore, how far is it going up?

If your getting more than a max of 1/2" travel by hand with little pressure, you may have a problem with the reverse band, or the rod on the servo piston is to short (Did you notice any rings or bands etched into the surface of the rod? if so, how many? BTW, carefully inspect the tip that engages the band, it tends to develop small fractures, and should be changed if present. If the tip in fact already fractured, and bits broke off, it would prevent the band from engaging fully, or alltogether.) The servo piston should be at the bottom of it's stroke when you drop the VB, if it's up in the bore, it may be stuck and possibly has been dragging the reverse band and wore it down, Thus creating your present problem.

Best way to see if it's still intact is to drive the truck in manual 1st before dropping the VB again. if it engages and engine braking is present, the band is fine, and your problem probably still lies within the VB.

 

[donaldthacker]

the piston for the reverse servo was as far as it can go up into the bore when I pulled the valve body. It is also very difficult to get out. I looked at the bore and the new double lip seal and I saw no evidence of problems there. like I mention when the exp. is on jackstands you can hear the tranny shifting and see the drive shaft trying to turn.
I have manual first. when I drive down the road say in drive and downshift it will not go into first if I let off the throttle. if I give it throttle it will engage into first., if no throttle it just will not engage until I come to a stop.

what I find stange is that it did this a few weeks ago and I did a temp fix to the vb until I could get a good one to rebuild, got it going and it worked just like before the problem arose, now it is back again whit the rebuilt vavle body

if I do a pressue test where do I attached the line for the gauge?

 

[BrooklynBay]

Check this thread on how to use a transmission pressure gauge: http://www.explorerforum.com/forums/showthread.php?t=117998

 

[pj8847]

Going by what your saying, that the reverse servo piston is all the way up in the bore, It should return to it's "off" position (resting against cover)in all gears except for reverse and manual 1st. (someone correct me if I am in error) Something is preventing it from returning. You also said it is difficult to get out. Normally, a slight tug or pull on it should get it to pop out of the bore, if you have to wrestle it out, there is a problem. (mine popped right out and gave me an additional bath of TF on my face... didn't taste good at all : )

If you're going to drop the VB again, take the piston /rod assembly out and inspect the piston/bore for scoring, also check the rod, and like I said, the tip in particular.

You can also take a long screwdriver and push it up into the hole where the rod goes and push up on the band to check if it's ok. As soon as you feel the screwdriver touching, you shouldn't be able to push it any farther than what I previously said, if you can, something may in fact be wrong.

Your lack of downshifting to manual first from drive throws up a flag, you shouldn't have to let off the throttle or come to a stop for it (low or manual 1st) to engage. You should get almost immediate engine braking once it's put in that gear.

 

[donaldthacker]

the piston is as far up as it can go, I will pull it back down and check it out.

as far as the manual 1st, when I am in drive and manually downshift it will not go into first unless I am giving it throttle.
If I let off the throttle and downshift it will not engage into first, only if I give it throttle while downshifting will it engage