speedometer drive gear

[bunghead]

Hey everyone. I'm back to my on again off again help a friend '51 Kaiser sedan project. Thanks again to all who helped me get the overdrive working. Now it's on to the speedo. The problem is the drive gear is no longer keyed to the output shaft of the overdrive. The cable is good, driven gear is good and the speedo works when I spin the cable. When I stick a finger into the cable hole I can spin the gear on the shaft. Does anyone know if the gear can be accessed and replaced with the overdrive unit in the car by dropping the driveshaft and slipping the rear housing off the overdrive unit? I certainly appreciate any help or advice that anyone is able to provide. Thanks in advance.
Bryan

[kaiserfrazerlibrary]

You need the 1951 Kaiser & Frazer shop manual or the Borg-Warner Overdrive service manual to do what you want to do. 

[Fid]

Are you talking about this gear here -


If so, it is not keyed, it just slips over the output shaft, as does the one in front of it that turns the OD governor switch. If the OD works, it's likely the speedo gear is turning too but not definite. Is it possible the gasket was too thick so there isn't enough back pressure on it to allow it to turn? Also was the transmission replaced with a different type?  If so, the pinion gear on the speedo cable may not be meshing or it may be missing. Check to make sure the cable itself is completely seated in the tranny casing.  If it is and you're still convinced the inside gear is not turning, it is possible to just remove the end casing with the trans in the car.  Also, there are two snap rings that hold the rear bearing in place.  If either of those are missing, that gear may not turn although it seems the one that drives the OD governor would not either. The fact that the OD works leads me to believe that's not the case and you want to check how the cable fastens and the gear on the end of the cable first.

[bunghead]

Thanks for the replies gentlemen. I do have the shop manual. I just don't see in the manual whether or not I can pull the back housing off while the unit is in the car. The overdrive is working. I've pulled the cable out of the housing and it is good. the driven gear is good as well. It is securely fastened to the piece it attaches to. The end of the cable is square and the gear assembly definitely drives/spins the cable. I am certain that the cable housing end is seating completely in the trans/overdrive case. I can stick my finger into the case and easily spin the drive gear (yes, the one in your photo) on the output shaft. I don't have my manual here with me but I'm quite certain that it states that the speedo drive gear is keyed to the output shaft. Perhaps there were/are variations? It stands to reason (at least to me) that if I can spin the drive gear with my finger, the drag on the cable spinning in the housing is preventing the gear from turning with the output shaft.  I don't know if the trans was ever replaced but it does not appear to have been. There is enough crud caked to everything that if it ever was changed, it was long ago. The car is all original, solid and rust free with about 70,000 miles showing. With my newfound knowledge, thank you Fid, I'll yank the back of the overdrive and see what I find. Nothing is impossible to fix!
Bryan

[Fid]

The transmission in the picture is a T-96 for a Henry J so perhaps the one used in the Kaiser is keyed. Sorry if I caused any confusion. I've always wondered how it worked in the J and I was assuming the Kaiser was similar.  If the manual says it's keyed, I'd go by that.  I checked my 1951 Kaiser shop manual and found no mention of that gear being keyed and you can't really tell in the diagram on page 131.
What is does show in all the diagrams is the mount is on the front/transmission section so you  should be able to remove the OD case/cover with the transmission in the vehicle.  I've done it on the J a couple of times.

[bunghead]

Dropped the driveshaft, pulled the rear of the o.d. housing and the output shaft bearing. The speedo gear is keyed to the shaft with the same key that secures the o.d. governor drive gear to the shaft. The key does not extend the thickness of the speedo drive gear but it is enough to keep the gear keyed to the shaft despite about .070-.075" fore and aft movement of the gear on the shaft with the gear, bearing and housing all in place. I'm left with thinking that the drive gear was slippery enough with gear oil that I only thought I was spinning it on the shaft. And, the driven gear must be worn enough that it is not engaged properly with the drive gear. At this point the only thing I can think to do is try to find another gear for the cable and see if that solves the problem. Thanks again for the help and advice.
Bryan

[Fid]

You probably know  this, but different gears were used depending on the rear axle ratio and engine combination. According to the '51 Kaiser shop manual, the OD equipped cars use the 41/9 (4.55) rear end and the 20 tooth gear for the speedo. Gears are available at Walcks 4 WD. They have several listed here -

https://walcks4wd.com/catalogsearch/result/?q=Speedometer+gear
 
and even if they don't have the correct one, one of these may serve you if you can't find one.
I know the 18 tooth one is an exact replacement for the Henry J but the Kaiser parts book lists a different number for it.  Hopefully someone can clarify if the HJ and Kaiser used an interchangeable speedo cable gear. If they are interchangeable between HJ and Kaiser, the 20 tooth one is what you need.

[bunghead]

Thanks again Fid. I have the 20 tooth gear and after looking at it the teeth do look quite worn. Having eliminated everything else I'm quite sure this is the problem. The gear is marked SW (Stewart Warner, I assume) 448288. I'll check Walcks. Thank you, thank you, thank you,
Bryan