Can someone tell me what makes the rear servo move forward and activate the rear band.
I have rebuilt my trans and still no reverse-
New o-rings on servo were installed and bore cleaned.
What in the VB if anything make the rear servo move.
My model does not have the large spring on the back side (however that would keep it away from band even more).
There is little room if any between the servo cover and piston for fluid.
How does fluid move it.

Any help with how it works would be great- Thanks

 

The passages are internal for the fluid to operate the servo. First thing to check is the strut being in place. The servo can work fine, but if the 'other' end of the band is not anchored by/to the strut, it won't do anything... You can check by using a Phillips head screwdriver or metal rod in place of the servo piston rod to operate the band. If you go straight up through the hole, you should find the 'pocket' in the band that the servo rod uses for apply. A long Phillips should be able to move the band 'so far' before it contacts the drum and gets immobile. If you meet no resistance, the band may have fallen off the strut. If you are a good manipulator, and loathe doing another R&R, you should be able to move the band back into position, and get the band to hold the strut in place while you re-install the servo piston. Other than that, it could be either the solenoid/valve body or endplay adjustment{allowing 'line' pressure to bleed off???}. If you have the proper O-rings installed, the servo should work even if a bit leaky.
You could also use the servo piston to manually apply the band by just moving it in the bore. If it bottoms out, {does not run into significant resistance before reaching end of travel} the support strut being out of place idea still applies.
tom

 

Thanks alot-
I was trying to get as much knowledge as I can before removing pan again- I may have time tomorrow or Monday to do it and will probe the servo hole and look for a spring back action when applied with long screwdriver.

I do remember that the servo seemed to go in very tight and I thought to my self how is fluid going to push this- so when I drop pan I will see how easy it moves in the bore.

Question:
I did not think a solenoid activated reverse- which one is it? It would be wonderful to find that was the problem.
Again- thanks for helping me figure how the reverse works.

 

Heck I don't know about the solenoid, just that the trans is solenoid operated run by an electronic computer rather than a hydraulic one. There is one solenoid that fritzes with the line pressure, modifying it based on throttle input, speed, and ??? whatever for firmer or smoother shift. May have dropped line pressure in R to prevent 'clunk' of the driveshaft, then not bothered to raise it back up??? Or it may be pure hydraulic via the valve body. I'm not gonna look it up in the DVD's as I'd have to fire up a different computer. Better off posting down in the transmission and driveline section further down in the web site forum page.
tom

 

Thanks- I was reading about doing a pressure test- I have the ATSG manual and have to read up on it more- Will keep you posted- thanks for all the information.

 

If, or when, you take the pan off, you could check for air tests in the ATSG manual. We used to use a blow gun with a red shop rag as 'gasket' and use air to apply the clutches and servos prior to installation. If it worked with air, it ought to work with fluid was the theory I think. The manuals used to point out the air test points in the valve body where you would apply pressure. If things worked, you would hear a thump as stuff cycled. ATSG is {was..} the best out there. I thought that ATSG wrote the manuals for Ford...
tom

 

I hope your right on the air testing- I did see that in a you tube video- I hope mine can be tested this way.
Update- I finally drove this truck for the first time today in the yard- did not want to go far in case she left me stranded- in Drive hardly any power and sputters- in 2ND ran much better but still not right went 3 laps around my 3 acres and parked it again.
I got to thinking- was are the signs of a bad torque converter?
Could this be why in gear she lacks power?
What are sign of a bad pump in a transmission?

I messed around with the door switches and freed them up so dome light works correctly now. Parked back in garage- This week my goal is to read up on manual and see about pressures and air testing.

I will keep you posted- Thanks alot

 

Hardly running and sputters are not caused by the transmission. Unless the TCC lockup is engaged, which would make idling at a stop very problematic. if the converter had fallen apart {rare} internally, it could have locked the outer shell, driven by the crankshaft, to the inner turbine parts, or broken loose the 'stator', which is fixed in place internal to the converter. Those failures would have locked the converter solid, or you'd hear grinding noises ... for a while ...
I would check the manual lever position for putting the valve body in exactly the right place for the different gears. Make sure there are the correct number of 'detent' positions, {count them} as you move from P to D or P to 1 or 2. Pull the lever toward you so you don't feel the mechanism in the steering column, or push the button for floor mount, so you can feel the detents as the lever moves. If the lever is off, it could cause the valve body to be in two positions at once.
If you are careful and clean, you can catch your fluid and filter it through cloth and re-use it when you drop the pan. Just be careful to NOT get that last dreg out of the pan that has the 'stuff' floating in it. Most everything would be caught by the cloth {diaper?} or settle to the bottom of the drain pan. You do not have to put all new fluid in...
Check some stuff, and get back
tom

 

I did notice that when reassembly it talked about an alignment tool for the lever adjustment- I do not have one and could not see how it worked- there is a slot and I have moved it a few times in 3 positions (it only moves about 3/16") and I think I have it best.

I cant stop thining about this truck and want to fix it- Again on TC -
Last night I started it up (fires rt. up) idles good for about 2 min- then sems to get low and perk up- so I left in park and raised idle and held it to about 2K if that - I noticed it want to stall or stumble and then come up again while I did not move pedal.
SO thinking now it may not be TC like you mentioned- no grinding or weird stuff.

I want to get a pressure gauge and measure fuel and the trans pressures- before I take pan down again.

Just dont think I can get it 4 miles to trans shop to put on scanner.
Want to get her running better first.

Thanks a million for the input.

 

The wandering idle sounds like it got into 'closed loop' after warming up. Before that, the computer just sends a 'richer than normal' amount of fuel to the engine because it doesn't have feedback from the O2 sensors yet to trim the flow. Once the O2's warm up, the computer adjusts the mix based on multiple inputs. MAF/MAP, ECT, ACT, MLPS, psps, bobo, and maybe more. Mass air flow/Manifold absolute pressure, engine coolant temp, air charge temp, manual lever position switch, power steering pressure switch, brake on brake off, A/C compressor clutch, and heaven knows what else is not monitored. These all change running and indicate load or no-load on the engine, so the computer will bump the idle to take care of the expected load, when, for example, you are parallel parking and are using the power steering at idle to maneuver.
An unstable idle, and miss while running above 1k, indicate loss of spark or loss of fuel supply. Or an air leak that is 'coming and going', such as one in the bellows after the MAF in the air supply ducting.
tom

 

Thanks
I am going to take off coil pack now and I called Carquest- they test them .
Last nite I did a dark wet test by spraying all over coil and wires- NO Arc at all anywhere.
I have been able to clear 1 code with the DPFE- but the bank 1 (P0135 code) O2 sensor needs replace- I may change that now to be sure that is not throwing things off.