No drive to banjo?

K

keeeef

Member
Not getting any drive to rear end of my 36 pickup. Jacked it up put it in any gear but wheels not moving!

I can hear movement form trans/u-joint area as I release clutch and speedo moves up as I increase revs but wheels not moving. No nasty noises or clunks.

Truck was fitted with a 4 speed trans which was badly worn but have just fitted a '36 3 speed.

What should I check first?

Thanks
 
What happens if with both wheels off the ground, trans in gear, and you rotate one wheel.
Try again with only one wheel off the ground.
 
Ok just tried with both wheel off the ground and trans in gear, both wheels have slight resistance when turning. With right side wheel only jacked up there is a lot more resitance/drive.
 
When both up, do they turn opposite directions when you turn one?
and with one up, does it indeed turn, though with drag?

If the differential is in working order, both wheels should turn opposite directions when the driveshaft is locked(trans in gear) with both off the ground

with one wheel on the ground you should have a direct connect from the single wheel through the gears and into the drive shaft, if the trans has the drive shaft locked then the single wheel should not turn.

If the single wheel is turning, which it sounds like it is, but with drag. I would guess you have a broken drive shaft or pinion coupler.
 
Ok, with both wheels off the ground turning the right wheel I have no movement to the left. With one wheel up I can turn easily but with some drag so sounds like something definately broken.

I will roll the axle back again and remove the tube from the rear end I guess. Not done this before but have searched a few previous threads.
 
Update, just jacked the rear up again with both wheels off the ground and now they are both moving when I rotate the right the left moves in the opposite direction? Fired it up and put in 2nd but only the right is driving. Could something be loose as it didn't move an hour ago!!
 
CHECK THE KEYS! It will at least make me feel better. If you have one broken it can jam and act like its fine and then break loose again. All the while causing damage to the hub and axle end. Neither one cheap to fix.
 
The speedometer is moving could be pin at banjo, under power with one wheel up and other down that's ok, could switch should get same results. Mark hub and axle see if slipping.
 
Ok will check the keys first. I can rotate the right wheel a full 1/4 turn before the left starts to move, does that sound right?
 
If it will not move both wheels down.
Jack up left side that wheel should turn under power. That side good.
Do same to other side.
 
George/Maine said:
The speedometer is moving could be pin at banjo.
Click to expand...

Gotta remember that the PIN does not drive the pinion. Driveshaft drives the pinion via the SPLINES. Pin only locks the two from sliding.

IF the rear wheels rotate in opposite directions (with pinion NOT turning) the spider gears are probably OK. Sounds like drive shaft broken somewhere behind speedo gear. DD
 
Ok, just thinking from first principles, if it is in gear and idling in first, clutch engaged and not moving, if an axle key has sheared, then the end of the shaft will still be rotating. You will be able to see the nut turning round.

Similarly, if you leave it in first with the engine off, jack up one wheel, if the key has sheared the wheel will turn but the end of the shaft and the nut will remain still.

To be honest, I can't imagine a key shearing but there being no drag on the hub.

If an axle shaft has snapped the wheel can be pulled out of the axle (if jacked up)

I think it has not gone back together properly. (although I am struggling to think how that could be).

So heres a question. Is the 3 speed top loader a straight swap in every respect for a heavy duty 4 speed? UJ the same? Can you just swap the boxes at will?

Does Keeef need any other parts to match his torque tube to the new gearbox.

Keef, did it all seem to go together ok? Did there seem to be anything wrong as it was going back together?

Mart.
 
Hi Mart

I fitted the u/j that came with the 3 speed. The 4 speed has a larger diameter at the trans end but both are the same size going into the tube. All went back together fine.

Will jack it up again tomorrow and check if the axle will pull out or if the nut is rotating.

I had this problem before I changed the 4 speed at the weekend which had badly damaged gear teeth and was locking up under load, ie trying to move back and forward on my gravel drive. It now shifts fine with the wheels jacked up but no drive with it on the ground.

Are the keys you mentioned the ones that slot in the stub axles when the drums are removed?
 
It is unlikely that you have 2 broken axles or keys broken.
Remove plug to put oil in rear end and move car and see if any gear movement.
IF you see movement my guess pin at end of driveshaft is broken.
 
The pin only stops the splined parts sliding. It doesn't transmit power. You only need one broke axle or one sheared key to stop transmitting power.
Martin.
 
Do you mean these pins? Borrowed pic from another thread.
 

Attachments

  • pin.jpg
    pin.jpg
    63.7 KB · Views: 60
You must log in or register to reply here.
Back
Top