porsche 915 - no 5th and reverse

Last night was not a good night for the race car

Because I’m a idiot I dropped it off the jackstands, now add fixing driver side door to the long list of repairs.

I plop down in the drivers seat and am overwhelmed by the stench of cat pee. Then I feel my pants getting wet. GREAT.

The job for the evening was trying to get my transaxle to work. I have a Porsche 915 bought of craigslist, with a kennedy engineering adapter. I’ve never been able to get it into 5th and reverse. Last night I disconnected the shift linkage and got down there with a big pair of vice grips to see if I could get it in to those missing gears. No dice. It rotates freely into 1-4th, but you can’t turn the shaft any further to get it into 5th and reverse.

What are the possible problems here? Is there anything I can do to diagnose/fix with the trans still in the car? Dropping it is going to be a freaking nightmare that I don’t have time for.

Just a quick google: http://porsche.wikidot.com/porsche-915-transmission-repair-tutorial

Apparently the 5th-Reverse gears are in the 'nose' of the transmission. Is that accessible with the transmission in the car?

I've never been into a 915 transaxle, from this Automobile Atlanta pic it's set up like a Bug unit. That means the main selector rod has to engage with the forks on the same inside.

There's a lot more pics on their site so you can get an idea of how it's laid out (gears, shafts etc).

The 5th selector rod (#19 in this pic) is probably not in the neutral position. The interlocks are supposed to keep this from happening but from personal experience this isn't always the case, I once dropped a Mazda transmission on its nose and damn if one of the selector rods didn't do just what you describe. I have, on other units, pulled a drain or fill plug etc then used a long screwdriver to wiggle/yank on stuff till it pops into the desired position. Sometimes you can do the same with a piece of coat hanger wire, welding rod etc.

It might be possible to get the nose off in the car.

Edited, stupid iphone autocorrect.

Ringer the nose off?

I'm pretty sure my uncle would do that to me when I was a kid. I was 14 before I realized it was just his thumb.

Isn't the 915 a dogleg box? If so, wouldn't 1st/reverse be on the same gate?

The 901 was dogleg Everything I've seen for the 915 was reverse was down and right

icaneat50eggs wrote: The 901 was dogleg Everything I've seen for the 915 was reverse was down and right

That is correct. 5th/reverse are in the same plane, as a normal 5 speed.

I'm not sure but I think the 915 was available as a four-speed. Are you positive that 5th gear is there? Reverse would still be there, of course.

Ah. Thanks for the update. I should have researched that first :)

The 4-speed bit is concerning though.

I've never heard of a 911 4 speed, save the 930(911 turbo) box. Maybe the 912's had a 4 speed, but they were 901 based, not 915.

Edit: I was wrong, There was a 4 speed 915.

I had thought of the 4 speed thing. And while I'd be ticked about not having the advertised 5th gear, no reverse is the bigger deal, and it still should be there

I looked up te part number it's definitely a 5 speed

In reply to icaneat50eggs:

No, its definitely a 5 speed case, who knows what might be inside said case decades later after an unknown number of rebuilds.

If you can get the nose off, you can easily find the problem. 5th and reverse pictured.