Had to call a tow truck today

Rob Channell · 05:56 PM

I had to call a tow truck today. I was cruising along in my 1972 911T when something popped and the car started bucking like there was a transmission problem. I coasted to the side of the road and tried a gear or two. It would grind if I tried to put it in gear and the neutral positin would try to move the car some if I let the clutch out.

I am thinking that the clutch is the problem and there are pieces jammed in there. Any thoughts?

It's a bummer because I haven't even finished installing my muffler and rear bumper on the other car yet. Looks like it will be Miata city for a while until I can finish?

After I get the SC muffler finished and back on the road I'll drop the engine/tranny in this one and pop them apart to see what's what. I guess I am hoping for clutch rather than tranny.

Egads! 911-less in Alabama.....

Zeke · 07-12-2006, 08:37 PM

Cable problem. The tube may have come loose in the tunnel. Or the adjuster is messed up. On a whim, I'm going to say tunnel tube. I used a u-bolt to bring the thing back to the side of the tunnel and secure it. Then I cut the excess threads off. You could barely notice this under carpet. This was not in the Ragamuffin in case someone is reading......

Rob Channell · 07-12-2006, 08:53 PM

I hadn't thought of that. I'll have to check it out. Thanks Milt.

nigel911 · nigel911's Garage

Any update?

Nothing worse than having to reply to the inevitable question from the call center operator - 'It's a Porsche, yes, really, a Porsche.'

Then the tow guy turns up...

Rob Channell · 09-29-2006, 10:12 PM

OK. 2 1/2 months later here is the update. It wasn't the cable although I was hopeful until I got under the car.

I really expected to find an exploded clutch. I removed the engine last weekend and seperated the engine/tranny combo to find the clutch and pressure plate looked fine. The throwout bearing was rotating freely. Everything looked OK from the outside.

I then turned my attention to the transmission. I moved the shift rod to put it in gear and then rotated both flanges in the same direction. The transmission mainshaft would rotate just a very little and then stop with a clunk feel in either direction. I started thinking maybe it had something to do with the selector levers letting it be in two gears at once and with some encouragement from a local Pelican (thanks, Jim) I drained the fluid and then peeked in the access cover.

It would rotate a lot further now before stopping so it was not locked into two gears. It did the same thing in the other direction.

When I opened the cover the first of these three pieces popped out and then I found a two more. They looked suspiciously like gear teeth

Crap. I then get more curious to find out if those are gear teeth or some other part broken off. So I decided to pull the front cover. I mean, what could it hurt? What am I gonna do, break it?

I removed the bolts for the front cover and it wouldn't come up but 2-3mm and then stopped. I was afraid to tap on it any harder and did not want to pry on a sealing surface so inside I came. After finding a thread on that exact problem here on Pelican I went back out and lifted the cover while tapping on the 5th/reverse shaft in the front of the cover. It was stuck, but started coming out and eventually the cover came off. Thanks guys.

Here's a couple of pictures of what I found. Notice the roll pin in the 5th/reverse selector about to fall out. I don't know how that happened. Poor assembly? Then there was the 5th gear set. There are several teeth broken pretty good on both gears so it's time for a new or new used 5th gear set.

Now I need to decide whether to send it to someone or maybe just take it to a buddy's shop and borrow some tools and rebuild it myself. I think I could probably do it but would be most worried about my ability to decide what parts are good enough and what parts should be replaced. Then there is that whole time/money thing. Anyway, I know this thing needs to come apart.

One thing I probably need to verify is about the front seal around the shifter rod. I can see a black seal around the rod from the outside of the front cover so I am guessing that my 1972 transmission has been machined to accept the later style shifter rod seal. Does that sound correct?

Anybody got a good used 5th gear set for a 1972 T?

later,
Rob

MBEngineering · 10-02-2006, 04:59 AM

HI Rob the pin sticking out on the 5th /rev selector rod is suppose to stick out as it is for the rev' light switch pin.

regards mike

Rob Channell · 10-03-2006, 03:30 AM

Quote:

Originally posted by MBEngineering
HI Rob the pin sticking out on the 5th /rev selector rod is suppose to stick out as it is for the rev' light switch pin.

regards mike

Hmmm. Maybe someone as clueless as me about this transmission should leave it to a professional.

Thanks for the explanation.

Rob Channell · 12-07-2006, 07:51 PM

Here's a follow up with a little more info.

In the following pictures you can see some marks on the pinion gear that I think may have happened when the pinion gear tried to squish one of the loose 5th gear teeth.

Is this pinion gear/shaft toast or is it usable and will just be noisier?

You can see the reason the 5th gear is missing teeth in the other photo. The 5th gear bearing has frozen and is extremely tight on the pinion shaft. If I remove the 5th gear and the shaft is messed up I am afraid I may have a large paperweight. If the shaft is OK I can just replace the gearset (assuming the pinion gear is OK). Another opotion I thought of if I cannot get the stuck 5th gear off would be to remove the mating 5th gear off the other shaft and machine off the gear teeth essentially turning it into a 4 speed with an extra neutral.(I'd rather not, but would at least consider this before trashing an other wise OK tranny).

What would you do? The car is a daily driver that I otherwise really enjoy driving. I am considering selling it in the next year as I would like to build a garage and could use the money as seed money to start the construction. I'd still keep the track car.

If Elombard still has (or had) his 1972 transmission available I'd probably just get his and put a 3rd gear synchro in it before installing it.

Rob Channell · 12-07-2006, 08:01 PM

Marked and Zoomed for detail

MBEngineering · 12-08-2006, 02:10 AM

HI Rob if you put 2 leavers under the 5th gear, the gear and the bearing sleeve should come off in one with the damaged bearing, the pinion is not to happy with the marks it has on it, the bits could have created more havoc in the box with the other gears, but until you get the 5th/rev' gears off and the center case we will not know??. As a quick fix I would see if the S/H trani' is still for sale, and if you where just round the corner I would have fixed the damaged one for you ASAP for you .

regards mike