So much for the indestructable A-568

[supercrackerbox]

So I lost 5th gear in the Daytona yesterday on the way to work. No clunks, grinding, or any noise at all. I just moved the shifter into 5th and there was nothing there. It felt just like a 555 I had years ago with no 3rd gear, which turned out to be that the shift pads and fork were completely shot. Knowing that would be an easy fix without removing the transmission, and having a spare 568 on the shelf, I opened it up tonight.




HOW THE DOES THAT HAPPEN?

[Ondonti]

I think I would blame that on manufacturing.

[shackwrrr]

Overtorqued nut most likely.

[86Shelby]

That's impressive!

[BadAssPerformance]

Nice work Adam, I haven't done that one yet!

how did the teeth look, like anything got in between there? Since 5th is cantilever out there it wouldn't take much to put some bending into the shaft.

[dme]

When I bought my 90 Voyager it did not have 5th gear. Opened it up and half the teeth were gone. Easy fix, but I always wondered what happened and how the trans survived with all of that metal floating around.

[supercrackerbox]

The teeth did have somewhat of a shine, but who knows if that is the cause or effect? Having to get to work, I drove the car 200 miles after losing the gear. To the best of my knowledge, this trans has never been opened up except when I re-sealed the diff cover over 50,000 miles ago. The car just turned 210,000 miles last week.

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Overtorqued nut most likely.

Is that nut still available? The service manual is pretty adamant about replacing it, and the one on my other trans has already been re-used at least once.

[135sohc]

Its not available anymore... Clean, red loctite and torque to spec.

[supercrackerbox]

I'll have to drag my welder out of the basement so we can fab up the tool to R&R that nut. Not that I'll need it to remove the one from the trans in the car . . .

[shackwrrr]

I forget the tool number but they show up on ebay periodically for around 10 bucks. I think I got mine for 7.

[Reaper1]

Can you take some good pictures of the the failure and the gears, ect ? I'd also recommend tearing it apart. You may find rogue bits in there someplace.

[shackwrrr]

I say grind it smooth, drill and tap, then use a bolt and washer. Just sport the 4 speed for a while. Then sell the gearset to a drag racer.

[135sohc]

Early 555 input shaft uses a backward spline and circlip that is readily available

[cordes]

I'll have to drag my welder out of the basement so we can fab up the tool to R&R that nut. Not that I'll need it to remove the one from the trans in the car . . .

IIRC It's one and 3/8ths for that flat section. I just use my large Williams adjustable wrench and and impact with a 27mm socket. That'll take it off no problem.

[supercrackerbox]

I forget the tool number but they show up on ebay periodically for around 10 bucks. I think I got mine for 7.

Eh the part number is listed in the FSM, but I've been itching to fabricate something like this for a while. I've got some nice pieces of plate steel left over from the rod-shift brackets for the 555 going into the GLHS. As if I'm ever going to finish that car . . .

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Can you take some good pictures of the the failure and the gears, ect ? I'd also recommend tearing it apart. You may find rogue bits in there someplace.

Oh it will get torn apart. Ray tore down the spare 568 tonight to see how it looked inside. It's mostly good, but I'll at very least need the 3rd gear fork, pads and brass. The one in the car has always shifted great, no noise ever, so hopefully we can use the parts from it. Basically take the best parts of each trans to make one good one, like we did for the GLHS (although that took stripping 4 transmissions, and I still had to source some parts).

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I say grind it smooth, drill and tap, then use a bolt and washer. Just sport the 4 speed for a while. Then sell the gearset to a drag racer.

I live 50 miles away from work, and it's all highways and interstates. The last two days of only being able to drive 60mph bumped my usual hour drive to nearly 1.5 hours. Of course I could do 75 in 4th gear, but I can't afford the fuel.

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Early 555 input shaft uses a backward spline and circlip that is readily available

I've got a 520 input shaft and a couple 525 shafts (and piles of parts from each). All my 555 stuff is in the above mentioned trans for the never-to-be-finished GLHS.

[Vigo]

Im gonna go with overtorque on the nut as well, although as Ondonti said ive seen (and actually done) similar breakage that was clearly a total fluke.

[Ondonti]

Im gonna go with overtorque on the nut as well, although as Ondonti said ive seen (and actually done) similar breakage that was clearly a total fluke.

Well to me manufacturing includes torqueing that bolt. I guess if one of us did a retorque then we just screwed up
My 5 speed still has 5th gear after putting 10 pounds of boost through it while towing tonight. I was thinking about this thread while driving.

[turismolover22]

Im thinking a bad casting. It happens. That spot would just get more brunt of force being an overhung shaft

[supercrackerbox]

A bad casting that took 210,000 miles before it finally let go?

[Ondonti]

A bad casting that took 210,000 miles before it finally let go?

Yeah, there are some 3.0's out there with bubbles in the cast cranks that just fail suddenly after seeming fine. Fatigue takes time but it eventually wins unless you give up first.