Dogleg not going into reverse. (Cause found)

[ByStickel]

So... I spent a day Saturday pulling parts from cars at a yard here in Montana. For the first time ever, I found an A10 200SX. That's the car that donated its engine and trans for the very first 510 I owned, built in the '80s, and bought by me around 1990: twin SUs, Konis, Interpart front bar/Dat comp rear, Panasports, factory tach, etc. I wanted another dogleg, so...

 

Turns out that the new-to-me trans (FS5W63A) I grabbed didn't want to go into reverse. I pulled the front cover (inside the bellhousing) to look at the actuation rods. I could get 1st-5th, but the shift lever centered itself on 4th and 5th. It was hard to tell if you were in the 2-3 gate or the 4-5. It was kinda hard to get to 1st, and only once or twice could I get reverse to engage. Most of the time the lever refused to go to R.

 

(then the 2-3 rod refused to return to neutral, and I couldn't even get the case off because it was all locked together at that point. I eventually got the front half of the case off, unpinned the shift forks, and was able to remove the rear case.)

 

Everything inside looks (very) good so far. I see nothing bent or broken. I can move the forks into all gears. When assembled, it acts as if the Striking Lever is crooked on the Striking Shaft (the part that controls left/right positioning) OR that the play between the Striking rod guide (holds your shift lever) and the Striking rod is too great, and that the mechanism just isn't able to get over to the left far enough to easily get reverse and first. (and center the shifter on the 2-3 gate)

 

Anybody know what's going on here, or have a similar issue?

Edited May 24, 2022 by ByStickel

[ByStickel]

I took it apart, and things inside the cases looked and measured good. Upon reinstalling the rear case, and working it through the gears, I discovered the problem. In the pic, we're looking toward the back of the rear case, toward the shifter. At the top is the Striking Rod, and it has the Striking Lever bolted to it. It's currently engaging the Shift Arm. Pay attention; there will be a quiz.

 

Anyway, it's the Striking Rod and Lever that rotate when you move the shifter left/right. The tip of the lever engages the upper Fork Rod (1st and reverse), the middle rod (2nd and 3rd), or it actuates that weird Shift Arm, which then moves the lower Fork Rod (4th and 5th). These rods aren't shown because you can't see a damn thing with them installed. What you can see are the 3 circular stops for the Fork Rods stacked on the left. They limit the rearward travel of the rods.

 

When I try to engage reverse, it most often tries to shift into 2nd. Sometimes it works, after shifting to 1st, first.

 

Why?...

Edited May 24, 2022 by ByStickel

[ByStickel]

Now we see the back ends ends of those Fork Rods. Each has a groove in it. As mentioned before, the Striking Lever engages each of the  grooves, one at a time (except for the lowest rod, which, again, is engaged by the Shift Arm, which is engaged by the Striking Lever.)

 

Ist and Rev. are on the right. In 1st, the rod is pushed forward, the opposite direction of the shift lever. Notice the groove on the left rod (2nd and 3rd). The rear of the groove has an extended section that overlaps the 1st/Rev rod a bit. Why? They did this to help you make a solid 1-2 shift. 2nd is a bigger target, essentially. Datsun cares about acceleration!

 

This is also why I'm having a hard time getting into reverse. My Striking lever is sagging. When I ask it to go far right, it doesn't quite make it far enough, and it's catching on the edge of the groove. It tries to engage 2nd and reverse at the same time. No bueno.

 

OK, so why is the lever sagging? It's not bent, so...

[ByStickel]

This is the part where we reveal the killer (of my shifting.)  This is the Striking Guide, or as we know it, the shifter mount. The shift lever ("Control Arm") has been removed, and we're looking down into the interior where the Striking Rod resides. I failed to mention that it's the Striking Rod that moves front-to-back, selecting 1st or Reverse, 2nd or 3rd, and 4th or 5th.  The two parts together tilt to select the gate, and they need to stay timed to each other. They do so with a keyway on each side of the Striking Rod. The Striking Guide has 'keys' permanently added to lock the Rod's rotation in.

 

And it all needs to stay clean and lubed, or it will wear out. Rubber dries out and crumbles. Road grit gets in. Metal on metal with some fine grit thrown in... leads to worn out keyways (and some making its way inside the trans, too). This lets there be excessive play between the Guide and Rod, and that's why my Striking Lever sags, and why it is contacting 2-3 when I want it to only touch 1-Rev.

 

The smartest and 'easiest' fix is to open up the trans and replace the worn parts. Putting it back together is a real chore. So, keep your shifter...um, Control Arm and Striking guide... sealed! It's pretty important.

 

I'm going to try to find a better used Guide and Rod. That's my next task. Please PM me if you have an extra.

 

Edited May 24, 2022 by ByStickel

[datzenmike]

Well done.

 

 

The whole point of the dogleg is to provide a straight line 4th to 5th and back again when racing. First being very little used. For a street car the opposite is more true and the up over and up to second and constant 1st and 2nd shifts is, well slightly awkward. I know that the large nut on the bottom that secures that post with the see-saw lever is what reverses the striking rod input to place reverse above 1st. Otherwise it would be ...

 

1 2 4

R3 5

 

.. and a really bizarre shift pattern. 

 

I have a long 31.5" dogleg minus the font and rear cases. This is the first time I've seen this actual part other than technical drawings.

 

 

[ByStickel]

I asked around about used parts, but wasn't able to locate anything. The 63A hasn't been overly popular because people hate 'different', and many folks believe they're going to go with huge horsepower in their cars... but never do. It's not surprising that parts aren't easy to come by.

 

So, I decided to fix it. Here are images of the Striking Guide (shifter mount) and Striking rod (what the base of the shifter rests in and moves fore and aft) You can see the rectangular male features in the former, and the grooves in the latter. Both are worn out.

 

I ground the grooves to make the entire length of the slot 'worn out'. 

Edited July 19, 2022 by ByStickel

[ByStickel]

I then looked for some material to make shims. In a victory for hoarders everywhere, I located the stainless strips I saved from my last set of old wiper blades. I could just fit 2 shims per side without the parts binding. Rather than trying to re-line the groove, I decided to enlarge my male bits, which sounds cooler than it is. After a few tries, I was able to bend up pieces that 'wrap' the protrusions, and once the parts are assembled, there's no possibility of them falling off; they're captured.

 

The last pic shows the parts together. The end cap will be reinstalled and peened. There's very little play, and the parts move freely. After reassembling the transmission cases (really tricky), I installed the shifter and checked to see if it worked. It did, and I can get reverse with no issue. Cool.

 

(2 weeks after buying this trans, I found another, already pulled, at another yard, saving it right before the yard was scheduled to be emptied, and everything crushed. This second dogleg seems to be in great shape, with no obvious issues. Now I have 2. I'm all set.)

[Stoffregen Motorsports]

Another one for the books. Nice work.