I can't get my C4 Servo back on...

techlaf · Oct 2, 2010

Changing the gaskets on my C4 that were leaking and now I can't get the servo back in. The spring is around the pin with the open mouth, and it feels like I'm stabbing it in there smoothly. I just can't push it in close enough to thread the screws.

Maybe the open mouth is not seating? Can you "feel" that or it's in when you can push the servo all the way in?

Steve83 · Oct 2, 2010

I don't know anything about slushboxes, and I don't have a C4 diagram, but is the pushrod engaging the band correctly? Is there air pressure inside the housing keeping the piston from sliding in? Is it anything like this?

techlaf · Oct 2, 2010

Hmm... it is sealing quite tightly when I push it in and the air pressure thing may be keeping me from pushing it all the way in. The C4 is in the truck so I can't see into the trans, only from underneath so I have no way of knowing if the open mouth is wrapping around the band properly.

Steve83 · Oct 2, 2010

Click it

pcf_mark · Oct 2, 2010

When you pulled it out did you hear a metallic tink-tink? There are these small cast iron things that go on the end of the servo pushrod and band adjustment studs. These go in through the bottom opening not in through the servo hole. They may have stayed in place but I doubt it because gravity and tension on the band wants to pull them out of place. Also the one on the band adjuster may have also come off. You can take the valve body off in a few minutes but you need to watch the manual linkage and kick down linkage when you put it back in.

74 Explorer · Oct 2, 2010

pcf_mark said:
When you pulled it out did you hear a metallic tink-tink? There are these small cast iron things that go on the end of the servo pushrod and band adjustment studs. These go in through the bottom opening not in through the servo hole. They may have stayed in place but I doubt it because gravity and tension on the band wants to pull them out of place. Also the one on the band adjuster may have also come off. You can take the valve body off in a few minutes but you need to watch the manual linkage and kick down linkage when you put it back in.

Ding, ding, we have a winner. What he said. ;D

73azbronco · Oct 2, 2010

double ditto.

techlaf · Oct 2, 2010

Don't remember hearing that sound, but then again I wasn't expecting half a quart of ATF fluid to gush out at the same time and may have been distracted keeping it off my face.

Sounds like I F'd up messing with this. Taking the valve body off could make things worse, but as it is I'll have to have it towed to a transmission shop so I guess I can try.

Viperwolf1 · Oct 2, 2010

The band strut is in the way. You'll need to remove the valvebody and take the struts out. Readjust the band when you put it back togther.

You have the wrong type of trans filter too.

techlaf · Oct 3, 2010

Those pics will help out a lot. I really appreciate it. So unbolt the valve body and it just drops down? Then I can position the struts into the open mouth of the servo shaft?

Previous owner must have tossed the stock filter and pickup tube because it had the wrong flat C4 pan filter and not even the preferable deep pan "hump" filter. I bought a deeper aluminum pan because my stock pan was badly warped and bent all over which contributed to leaks. The new deep pan came with the slightly deeper hump filter. I guess that is inadequate.

Even if I ordered the right filter and another pickup tube, wouldn't the pickup tube be too short since the new pan is deeper? Do any vendors offer a longer one? Are there specs around so I can get one made? I have handtools, a driveway, and very limited space or proper tools to fab much of anything.

broncnaz · Oct 3, 2010

More than likely its a swapped in C4 hence the flat pan. The deeper tubes are tough to find most people just make there own of of the correct sized tubing.

techlaf · Oct 3, 2010

Wish I had seen this sooner:
http://classicbroncos.com/forums/showthread.php?t=153380&highlight=valve+body+servo+band
Sorry Viperwolf, you seem to get the same questions over and over.

techlaf · Oct 3, 2010

Ok, got my servo shaft in and seated properly in the band strut. Are there any tips on getting the valve body back in?

"You can take the valve body off in a few minutes but you need to watch the manual linkage and kick down linkage when you put it back in." -Great advice, can anyone be more specific?

Viperwolf1 · Oct 3, 2010

I once posted the stock pickup tube size but I can't find it now. I think it's a 1" tube. Easy to make one that fits any pan depth.

Watch the torque on the valve body bolts when you put them back in. The big one are only 80-120 in-lbs. Small bolts (if you removed any) are about as tight as you can get with a nut driver. Get all the bolts started before you tighten any.

You'll need about 3 hands to line up the manual shift valve with the lever peg and the kickdown lever with the downshift valve while you hold the valvebody up and get the screws started. Take your time and get it right. Once the bolts are tightened test the shift lever and kickdown action before you put the pan on. Should have all 6 gear position clicks on the manual lever. Kickdown should move freely with a springy feel.

73azbronco · Oct 3, 2010

Your in for some wiggling of the shift piston on the VB, the shift detent selector on the case and and kickdown lever on the case, everything needs to be in the right place as you bolt up the valve body. You know the shift/piston is right when you can select each gear and it ratchets through them all using the gear lever outside the tranny body. You know the kickdown lever is right when you can move it and feel it push on the spring and it returns. Caution, do not force anything while aligning and putting this up. I had "fun" doing this on a bench with VB "UP", the second time it was easy. Your first time upside down under the truck, well good luck, it can be done, just imagine how it all goes together whiel you slide the VB up onto the two selectors.

If any doubt, buy an inch lb wrench, PO stripped two and I needed to helicoil them, not fun.

techlaf · Oct 3, 2010

I think I got it all lined up. For some reason there is one 3/8" valve body bolt longer than all the others. I can't seem to figure out which hole it's supposed to go in. Think I've tried every one, but my forearms needed a break.

73azbronco · Oct 3, 2010

one of the filter bolts is longer as I recall.

techlaf · Oct 3, 2010

Yep, that's it, it is the one filter bolt. There must have been one valve body bolt missing because I was careful keeping track.

But now I have a bigger problem. The bolt in the picture will no longer screw in and just falls out. It popped out and had some heli-coil looking stuff around the threads.

Viperwolf1 · Oct 3, 2010

techlaf said:
But now I have a bigger problem. The bolt in the picture will no longer screw in and just falls out. It popped out and had some heli-coil looking stuff around the threads.

That sucks. I stripped that hole once and now I never remove that bolt unless the valve body is out to take pressure off the spring. I had to split the valvebody and use a really tiny helicoil to fix it.

I can't get my C4 Servo back on...

Sr. Member

Attachments

Bronco Guru

Sr. Member

Bronco Guru

Bronco Guru

Full Member

Bronco Guru

Sr. Member

electron whisperer

Attachments

Sr. Member

Bronco Guru

Sr. Member

Sr. Member

electron whisperer

Attachments

Bronco Guru

Sr. Member

Bronco Guru

Sr. Member

Attachments

electron whisperer

Similar threads