Restoring 727 OEM Shift Cable

[designerlarsb]

Hello again guys:

so old smurfette Is getting her oem shifter reinstalled...properly I hope. [insert easy joke here.]

Anyhow, her all-knowing po did some 'custom' work to the cable mount brackets and related hardware in his failed attempt to fab (I think) an aftermarket shifter of some sort. All that I know is based on the cut up bracket pieces he left me and the jerryrigged vato zone cable in the pile of 'extra parts' thrown in the back of the rig. In the end he gave up...so to shift he used a scrap of angle iron in place of the cable clevis and pair of vicegrips for a handle. Classy!

Again I digress.

To date, I've done all my misc shifter parts sourcing (thanks Jeff), along with the usual rust cleanup, painting, and reinstall, and now the problem shows up when I go to adjust the throw of the new/old oem cable. I know I know, I should have ordered a fresh cable too, but this one seems decent enough still and is smooth operating for now - at least when not connected to the tranny. And I'll be honest. I'm cheap.

What's happening is that the shifter operates the cable - apparently as it should, and the clevis end moves back and forth pretty well. But the selector arm on the trans is so f*ing stubborn, the whole cable contraption bends and flexes just trying to get it out of park. I don't dare reef on it. I think that would just break/bend my new setup someplace(s). All along, it has required a pretty swift blunt-object whack to the selector arm to get into gear. Not 'hand' actuated at all. I thought this would be solved with the added leverage of the correct shifter...but apparently not.

I'm kinda at a loss now. I have read 727 guapo and there's a few similar-sounding issues in there, but I didn't see exactly the same situation, so I'm unsure of the relevance in my case. The suspects list includes nss, parking pawl or other mechanical damage...but I'm not a trans expert by a longshot. So I'm really just guessing. I want to start with the easiest things first, and I definitely don't want to be dropping the pan and rooting around inside it if I don't need to.

I'm crossing my fingers it's a simple fix, rookie oversight on my part, or other adjustment. Any ideas?

Here's a couple shots of my setup fyi.

 

[Danny Phillips]

I just reinstalled my 727 and the bracket on the trans looks like it was 2 pieces on metal welded together. The bracket you have looks like it should work fine. Try blowing the crap around the shift shaft and see if the shift lever is rubbing on the case. While I had mine out I replaced the shift shaft seal and throttle shaft seal. Maybe a little lubrication on the outside of the shift shaft might also help to loosen it up. As I recall trying to move the shift shaft by hand took some effort but definitely moveable. I got some good advice from trever (scoutboy74) maybe look thru some of my trans thread "727 puking oil from dipstick". Hope this helps. Danny

 

[Scoutboy74]

The bracket attached to the trans looks okay. I'm assuming you have a pin for the attachment to the linkage and it just isn't depicted in these pics. What we can't see is what you have going on at the shifter end underneath the access panel. Assuming again that the shifter you sourced from Jeff has the cable retention bracket attached to the bottom of it, that leaves one more piece to the puzzle. That being the bracket that is attached to the bottom of the trans tunnel which the cable passes through. So if you could shoot a pic down inside the tunnel with the cover out of the way and we'll go from there.

 

[designerlarsb]

Hmm. It's getting late now, so additional pics will have to wait till tomorrow at least. But I can tell you now that I don't have that middle bracket (19,20,21 in this diagram). As far as I can tell it's just for general routing of the cable jacket. I'll fab up something for that if you think that's really the culprit, but it doesn't seem like that one does anything mechanically significant for my sticky selector issue, so I haven't bothered so far.

Indeed I do have the clevis pin. I had it off in these shots as I was trying to actuate the selector manually and troubleshoot at the time.

 

[Scoutboy74]

Yes you're right. That one doesn't have any bearing on your issue. So tell me this. Once out of park, have you tried moving the selector through the gear positions with the cable hooked up? Aside from park, does it function smoothly everywhere else? Try it if you haven't. I have a hunch about what the issue is, but I need the above feedback from you to be more certain.

 

[Danny Phillips]

My shift cable has a clamp on the end of the gear shift selector as well as an adell clamp on the rear of the transmission tunnel for routing purposes. I do remember doing a few adjustments on the clevis pin on the shift shaft arm and the adjuster on the gear shifter itself to match the gear detents in the shift shaft to the detents for the gearshift. I still need a little fine adjustment to get the neutral/reverse safety switch. I just have to bump the gearshift forward to get it to engage. Danny

p.s. Trever will get you straightened out.

 

[designerlarsb]

yes you're right. That one doesn't have any bearing on your issue. So tell me this. Once out of park, have you tried moving the selector through the gear positions with the cable hooked up? Aside from park, does it function smoothly everywhere else? Try it if you haven't. I have a hunch about what the issue is, but I need the above feedback from you to be more certain.

Yeah, your hunch sounds promising. I tried that this evening. It takes a few light hammer hits directly on the selector arm to get out of park, but then clicks through the other positions with my thumb. I attached the cable and it operates it in any other position fine. The cable needs lube and adjustment obviously, but it seems likely usable in all the other gears. (it even goes from r back into park fine btw)

so what's next chief?

Fwiw: attached is an 'upskirt' shot under the shifter cover as well.

 

[Scoutboy74]

Oh, I love them up the skirt shots. well, this isn't real good news for you. So what I think you have going on here is most likely a problem with a specific part of the valve body. The parking pawl rod is secured to the rooster comb with a cir-clip. The notches on the rooster comb correspond to each gear position and they ride against a spring-loaded, steel detent ball that resides inside its own bore on the exterior of the valve body. This creates the detent/ratchet action as the linkage is moved back and forth through its range. The valve body is made of cast zinc, which is on the softer side of the metal spectrum. Over time, the bore where this steel ball lives gets slightly out of round, which allows the ball to move laterally in addition to the normal in and out motion. We're only talking a fraction of an inch, but it's enough to be a problem when trying to get out of park. Usually it is worse when parked on an incline. That's why setting the park brake before shifting into park is so important with these transmissions, especially on an incline. You don't want the weight of the rig working against the movement of the pawl rod and rooster comb the next time you go to move the rig.
There is a fix for this, but it isn't for the faint of heart. First, it involves removing the valve body from the trans so it can be dealt with on the workbench. That's the easy part of the job. Next, the rooster comb, steel ball, and spring must be gotten out of the way. Again, not that difficult. Then you order a detent ball and spring kit from a transmission supply place. It isn't expensive. Now is where it get's ugly. The bore for the detent ball has to be reamed out so the steel bore sleeve from the kit can be inserted. You can't just hamfist it with a drill bit. The hole must be reamed out perfectly straight, square and even. So you have to use a special reamer tool made specifically for the job, available only from a trans parts supply place. These tools are stupidly, ridiculously expensive, especially considering you'd be using it one freaking time in your life. So that isn't a practical solution for the average Joe. That's for blokes who play the trans repair game for a living. Perhaps one of your close, personal friends owns a transmission shop? Nah, I didn't think so. The other option is to source a replacement valve body and swap it in place of the one you have. Considering the price of the reamer tool and the ticklish nature of the repair job involved, a vb swap is by far the most cost effective and practical option available. I know this is a lot for you to chew on, so if/when you decide to go for it, shoot me a pm and I'll hook you up with a very reputable, online trans parts house and make sure you order the right shit. Sorry the news couldn't be better.

 

[designerlarsb]

Oof da. How much coin we talkin' here? I do actually know my way around the machine shop...is it just a precision ground reamer of a particular diameter or something more fancy and trans specific? Is it a job I could do with a boring head on the bridgeport mill at work?

Or should I just cut my losses and do the vb swap? How much is that option?

 

[Scoutboy74]

A new vb can be had for under fitty bones plus shipping. This is what the reamer tool looks like, so you tell me. Once the repair is done, it is better than original due to the steel sleeve which won't distort like the zinc hole can. The repair kit is pretty cheap, it's just that damn tool cost that gives one pause for thought. Of course, lubing your cable May help a little, but it won't make the problem go away. I think if you set your brakes or chocked your wheels so the rig couldn't move with the trans out of park, then hooked up the cable and selected park again, I betcha you'd have an easier time getting back out of park with the shifter. When the detent bore gets sloppy, any tension placed on the park lock apparatus, even from just gently rolling forward or backward against the lock a half an inch, can exacerbate the problem. By really paying attention to what you're doing before you go into park, you May be able to baby this thing along for awhile. Talk about a hell-bitch though when you can't get out of park when you really need to.