915 gearbox trouble... what to expect?

[xellex]

Hi guys, today while leaving from the front of my house, I heard a clunk noise (which I associated to some possible bump in the road) while I was in 1st gear. After shifting in 2nd I heard the same noise, and while trying to shift to 3rd, I realised I was loosing power and soon came to a stop.
I pushed the car back home, and it looks like it's not the clutch. The car shifts well through all the 5 gears and reverse, but it does not go anywhere. I'm saying that it's not the clutch, because while in gear, if I rev the engine, the speedometer (electronic)shows the speed that I should have.
The gearbox is a 1985 915 with a ZF original limited slip differential.
I'm gonna start dropping the engine and gearbox, but it would be nice to know what to expect while doing it.
Thanks in advance!

[john walker's workshop]

you probably broke a cv joint or an axle came loose.

[Arne2]

Originally Posted by john walker's workshop

you probably broke a cv joint or an axle came loose.

Wouldn't the limited slip still send some torque to the other wheel if one CV joint broke?

[yelcab1]

Originally Posted by Arne2

Wouldn't the limited slip still send some torque to the other wheel if one CV joint broke?

doesn not matter. When he crawls underneath to drop the engine, he will know whether his CV joint is good, or not.

[DRACO A5OG]

Oh damn, sory to read your troubles.

I hope it is one of the axels and not the main gear shaft.

Mine snapped at the second gear, at stand still I can shift to all gears but it would just rev and not move.

Check the drai plug and Open up the side access panel on the 915 and see if you find anything

Jim

[xellex]

thanks for the answers guys! But if an axle was broken, shouldn't it make some noise while revving in gear?
I'm dropping the engine and trans on monday, but I can jack up the car and check the axles in the meantime. But I don't think I'm that lucky to get away with such an easy fix...
Jim, looks like we're in the same situation. Did you fix yours?

[GaryR]

Originally Posted by xellex

thanks for the answers guys! But if an axle was broken, shouldn't it make some noise while revving in gear?
I'm dropping the engine and trans on monday, but I can jack up the car and check the axles in the meantime. But I don't think I'm that lucky to get away with such an easy fix...
Jim, looks like we're in the same situation. Did you fix yours?

Not if it came off on the transmission side..

[jrbennett]

If your speedo is increasing in speed, I don't think you have a problem with the gears or shafts.
Most likely an axle or C/V joint, if it is internal with the trans, it would be in the diff.
The diff or the axles can be fixed without removing engine/trans

[john walker's workshop]

a broken diff would be quite noisy.

[DRACO A5OG]

Originally Posted by xellex

Jim, looks like we're in the same situation. Did you fix yours?

.
Yeap, had to rebuild. Very painful experience

[xellex]

Thanks for all the help guys! It turned out to be a cheap fix... The bolts on the cv joint snapped on the wheel side of the left axle shaft.

[Hugh R]

You are very lucky that you weren't at speed.

[Jim Sims]

Typical result of loose CV joint bolts - these bolts are not intended to be loaded in shear which is what occurs if they are loose. Were the CV joints disconnected recently - in the last 5000 miles or so?

[quattrorunner]

My bolts broke at about 85mph!! Took my throttle cable with it and most if my hair that I had left. Now I'm bald and gray but at least I have my Porsche though for a second I thought I lost everything........very scary.