A4LD rebuild done, now onto shifting.

[ty.forestcom]

Okay first of all, thank you to everyone who has helped me this far. I’ve finished rebuilding my transmission and am pretty confident in it at this point in time. Truck drives forward for the first time in 24 years!

I have one problem however, it seems to be shifting wrong. Not late nor early from what I can tell. It shifts into 1st 2nd and 3rd and I have not tried going past 3rd for this reason. The truck seems to be mildy rubbing through gears. In other words it doesn’t shift very solid. It is almost as if when it gets into 2nd it is still a tiny bit in 1st. Same outcome in 3rd. It doesn’t seem like it’s dragging or making any bad noises but definitely shifting a little “soft”. I am thinking it has something to do with either my shift linkage, which I made sure to run through all gears from the transmission linkage and match to my floor shifter, with the truck up on the lifts. It was correctly placed in each gear to my knowledge as I went from the park position and all the way down to 1st from the linkage and the shifter matched each gear from above.

The modulator I had in the truck had no green or black stripe, so I got the modulator without one shown on rock auto. Modulator looks identical from the outside. The pin was poking out 1/8 or even 1/16 more than oem modulator though. I didn’t like that but as I’d already been through 3 tries with modulators and they didn’t match as close as this, I installed it. Could this have anything to do with my problem?

I installed and tightened bands by tightening the square head bolt all the way in and taking it 1.5 turns out. Then tightened nuts to spec. The man video I was watching at this point advised the 1 1/2 turns rather than the 2 turns recommended. He seemed VERY knowledgeable on the transmission and went into every detail like he was made to do it. I can’t say I’ve ever driven his transmissions, but his professionalism has me pretty confident he knew what he was talking about.
I did adjust the kick-down cable just as the manual told me to. Pulling it all the way out and setting the button. It is said to self adjust.

The problem is definitely subtle and the truck does drive but I don’t want to take it around anymore in risk that I’ll burn up the forward clutch again.

I would love any help and advice from someone who knows more than me. (Not at all hard to do).
I’m 16 and this is my first project car as I’ve said before, I’m working with well seasoned mechanics and this has them a little stumped as well.

Thank you everyone!
-Tyler

 

[franklin2]

I have never worked on this transmission, but there are two main ways they varied the trans pressure on most all auto transmissions;
1. Road speed
2. Engine load

Most all transmissions have a governor. It monitors the road speed and varies the internal pressure of the transmission. The pressure in the transmission is what controls the shift quality and timing. Along with the governor, the engine load is added in to determine shift quality and timing. The earlier transmissions used a modulator that monitors the vacuum from the engine. The later ones used a cable to the throttle butterfly.

From your description, sounds like your trans uses a modulator to the vacuum system. Most vacuum modulators are adjustable by taking the vacuum line off and taking a small screwdriver and turning a screw up inside the nipple. Shortening the travel of the pin will make the shifts soft and early. Lengthening the pin will make the shifts later and more firm, by increasing the pressure in the transmission.

 

[ty.forestcom]

Thank you sir! I am planning to try this today in hopes it could be my problem! I will let yall know asap

 

[ty.forestcom]

I have never worked on this transmission, but there are two main ways they varied the trans pressure on most all auto transmissions;
1. Road speed
2. Engine load

Most all transmissions have a governor. It monitors the road speed and varies the internal pressure of the transmission. The pressure in the transmission is what controls the shift quality and timing. Along with the governor, the engine load is added in to determine shift quality and timing. The earlier transmissions used a modulator that monitors the vacuum from the engine. The later ones used a cable to the throttle butterfly.

From your description, sounds like your trans uses a modulator to the vacuum system. Most vacuum modulators are adjustable by taking the vacuum line off and taking a small screwdriver and turning a screw up inside the nipple. Shortening the travel of the pin will make the shifts soft and early. Lengthening the pin will make the shifts later and more firm, by increasing the pressure in the transmission.

So I did some work with the modulator today, definitely was the bigger problem here. I reinstalled the old modulator for the time being to test my problem. Shifted great and ran through 1st-3rd like a top. Noticeable strong shift now. I ordered yet another modulator but this time from parts geek. It’s said to fit my model and the A4LD. So fingers crossed it’s the correct one.

There is a noticeable delay in reverse, I have no problem with this but am trying to read up and see if it is an indicator of another problem. Haven’t found anything yet.

The truck shifts amazing going from low to overdrive drive manually. It shifts the same automatically in overdrive or drive if I’m easy on the throttle. Once again not a problem for me. It seems to skip 3rd a little bit if I’m harder on the throttle. Any ideas what could cause that? I’m thinking modulator.

My modulator is BAD! I am not taking the truck out until I find the correct one. It had a bit of oil in the vacuum line before the rebuild. No plans on keeping it. It has been awfully hard finding the correct one. Not the shape or anything but the length, the pin pokes out 1/4 more than oem. Not 1/8 like I stated before. I’ve been through 3 so far, the one that came with rebuild kit was a c3 modulator. Ordered 2 from rock auto that both had the pin sticking out too much.

I stopped ordering from the rock for a separate dispute this last month. Picked up a new modulator from parts geek that looks the same as oem. The only one so far that isn’t silver, rather bronze. Napa could only sell me the ones I’ve got from rock that had too much pin length. Ford oem had discontinued the part long ago. Unfortunately there is no way to tell it will work until I have it in person, as the pin length is not in the description.

Does everything I’ve stated about the shifting sound to an expert like thats my problem? I’m fully open for constructive criticism here, I am not knowledgeable and would love more advice from you or anyone else!

Thank you sir!
Tyler

 

[franklin2]

I thought on most modulators the pin can be pulled out? if it can, what happens if you compare it and swap it to one of the new modulators that you have?

That was a caution I read when changing the modulator, sometimes people lose the pin and don't realize it,, and then re-install the modulator and then the trans will not shift correctly.