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dead transmission?

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So my car goes into gear, clutch is working fine, but the car isnt moving anywhere..

I can put it in gear and let the clutch out, the spedometer rises a little (why is that?) and I hear a whirring like sound. Sounds something like sandpaper on metal.

Is the gearbox dead? Does the spedometer read from inside the transmission?

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Ok, this is good-

I suspect that the output flange on your trans is stripped

(it's an old problem)

but to check it, get someone to look underneath and see if the driveshaft's turning. Jack the back end up first, and support it REALLY well (because this is a good way to kill yourself)

and then see if the rear wheels turn. If they do, put the parking brake on.

No driveshaft= bad rear flange.

Cool- this hasn't come up much...

t

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If the drive shaft spins, rear end is gone, but the speedo moving shows you are getting power thru to the tranny out put flange.

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I have the same problem on my '74tii (the noise and no movement). In my case it is the rear stub axle and stub axle flange on the right side. Along with checking to see if the driveshaft spins, check to see if either of the short axles spins as well. I already made the mistake of not looking... anybody need a 3.64 diff?

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I also experienced a right side stub axle failure once upon a time.... the symptoms you described fit. Easy to verify if one axle is spinning and the wheels remain motionless.

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Examine the bolts that hold the rear axles to the diff. they have been known to back themselves out and break, one by one. In this case the driveshaft will move but neither rear wheel will. And without a limited slip diff, you won't go anywhere if the bolts are broken only on one side.

The tranny output flange failure described in another post is primarily on 1972 and 73 cars with coarse spline flanges. Seems a batch of flanges were improperly heat treated by the supplier. The design was changed in early 1974 to a much finer spline, and that solved the problem.

BTW, since the speedo works off the tranny, the problem can be downstream and the speedo will still work.

Hope it's something easy like broken axle bolts...post what you find.

mike

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Thanks guys, I'll get under there and give the rear end a good looking at.

My girlfriend said there was a loud noise before it happened, described it as something dropping from the car.

I'll post what I find.

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left side rear axel was resting on the exhaust, the bolts are all stripped out and some are bent!

problem solved, It was *very* obvious once I looked back there, I just assumed something broke in the transmission.

thanks to everyone

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FYI... when you are sourcing replacement bolts, I would encourage you to make some eqnquiries with local industrial fasterner supply houses.... they may be able to offer advice and possibly even provide some options in terms of high-strength bolts.

My experience many years ago when I first encountered this situation is that I could obtain superior quality industrial fasteners at lower cost that the original BMW part.

Of course that leads to the next question... what is the optimal faster? I dunno, but perhaps some of the mech. eng types among us might chime in with some good advice. I would be tempted go go at least one step higher in terms of hardness/strength compared to the original spec item.

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