Rattle in shifting mechanism Options

[andreic]

Hello,

I have a 1972 with the early (tail) shifter mechanism. The transmission shifts very well after I replaced all the bushings and adjusted the shifter.

However, in second, third, fourth, and fifth gears, as I accelerate through 1400 rpm there is a loud rattle that seems to come through the firewall. I believe it must be coming from the connection between the front shifter bar (the one that goes through the firewall) and the rear one. Both plastic balls at that connection were recently replaced in the shifting mechanism, but that part of the shifter still does not feel tight. The balls used were the black plastic ones supplied by Pelican.

Does anyone have any experience with these? Is there any other supplier of the plastic balls? If not, is there anything else I can do to eliminate the rattle there?

Thanks,
Andrei.

[dr914@autoatlanta.com]

you will have to localize it. If in the tunnel, could be a broken clutch tube, or a loose connection where the tunnel rod attaches to the short link rod and maybe the clamp is rattling against the tunnel. On the other hand, could be the loose heater control valve rattling against the engine mounting bar. Also could be an air guide plate rattling against the rear shift bar

Hello,

I have a 1972 with the early (tail) shifter mechanism. The transmission shifts very well after I replaced all the bushings and adjusted the shifter.

However, in second, third, fourth, and fifth gears, as I accelerate through 1400 rpm there is a loud rattle that seems to come through the firewall. I believe it must be coming from the connection between the front shifter bar (the one that goes through the firewall) and the rear one. Both plastic balls at that connection were recently replaced in the shifting mechanism, but that part of the shifter still does not feel tight. The balls used were the black plastic ones supplied by Pelican.

Does anyone have any experience with these? Is there any other supplier of the plastic balls? If not, is there anything else I can do to eliminate the rattle there?

Thanks,
Andrei.

[Mikey914]

I have one, unfortunately / fortunately it works well. My suspicion is that it's actually something to do with the engine mounts. Probably on the bar. It's harmonics that cause the vibration and it's just not fastened down all the way.
My .02

[andreic]

I should say that I looked all the way under the car, and nothing touches the long shifter bar that is behind the firewall. When the car is in 1st or reverse, if I hit this bar with my hand, no rattle. When the car is in 2, 3, 4, or 5, banging on it with my fist creates rattling noise inside the linkage (where the two plastic balls are, inside the plastic housing).

A.

[Mikey914]

Got me on this one.
Interestef to soo what it looks like inside.
Shouldn't be anything loose inside. (IMG:style_emoticons/default/WTF.gif)

[rhodyguy]

Did you replace the bushing in the carrier behind the shifter? In 1&r the linkage is under a side load.

[Dr Evil]

Bushing on the pivot ball on the firewall?

[andreic]

All the bushings were changed. To be more precise, these were the bushings changed: 3 circular bushings (one behind shifter, one on the firewall, one at the back of the car where the shifter bar connects to transmission); 2 plastic balls in the linkage between the shifter bar that comes from the car and the one that goes along the engine and transmission.

I also think the fact that the shifter bar is under a side load in 1st/reverse is what makes a difference. But I can't tell where it rattles when it is not sideloaded.

Dr. Evil -- what do you mean by "Bushing on the pivot ball on the firewall"? I replaced the round bushing that the shifter bar goes through the firewall, and the two balls, one one on the shifter bar itself, and one on the small 2" bar that bolts into the firewall.

[Dr Evil]

All the bushings were changed. To be more precise, these were the bushings changed: 3 circular bushings (one behind shifter, one on the firewall, one at the back of the car where the shifter bar connects to transmission); 2 plastic balls in the linkage between the shifter bar that comes from the car and the one that goes along the engine and transmission.

I also think the fact that the shifter bar is under a side load in 1st/reverse is what makes a difference. But I can't tell where it rattles when it is not sideloaded.

Dr. Evil -- what do you mean by "Bushing on the pivot ball on the firewall"? I replaced the round bushing that the shifter bar goes through the firewall, and the two balls, one one on the shifter bar itself, and one on the small 2" bar that bolts into the firewall.

I believe you addressed it as it would be the one on the stud on the firewall where the rod pivots.

If it only rattles with side load, then its because the rod is loose in the shifter cleat on the tail cone. Check for wear. You can weld up and reprofile, then harden the shifter ball end at the tranz. If the cleat is worn, you need to replace that part, its not too bad.

[Dr Evil]

Here is the Porsche parts diagram (available online for free).

Replacement of numbers 6, 9, (10), 11, 22, and 40 is recommended. The second ball on 40 is the one I was initially referring to. Firewall bushing not shown (weird).

The red arrow annotates the end that has a ball in it that wears down and causes sloppier shifting and rattle. The rod is not very tight in its habitat to begin with.

[andreic]

Dr. Evil: I did not replace 6, 9, and 10 (they did not come as part of the standard Pelican parts bushing kit), but I don't think the rattle is from there.

I changed 11, 40 (2 pcs), 22 (3 pcs).

The end of the bar #43 that you put a red arrow on is all steel. Was there supposed to be a metal or plastic ball at the end? The little vertical end does feel loose in the part on the transmission where it attaches (is that what you called the cleat?). If those parts are worn out, what needs to be replaced or repaired? Should a new ball be welded on the end of the shifter bar? Or the cleat replaced, by taking some part of the transmission apart?

Thanks for all the help.

[andreic]

I looked up now the parts diagram. Is what you call the cleat part number 16 in the picture below? And how would I know if it is worn out?

[Dr Evil]

I looked up now the parts diagram. Is what you call the cleat part number 16 in the picture below? And how would I know if it is worn out?

Yes. If it is wallowed out (obvious wear making opening wider where the ball sits), or if it is not square.