VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Gearbox rebuild

Evening all, with this rebuild of 2 Chev 4 gear boxes have noted some oddities and differences,firstly all the bushes I have removed were split they all were the sintered type with a dimpled face and half had the Chev logo on them, any one have an explanation for this, I would have thought it odd, Also only 1 box has the splash device on the cluster gear, it also has a big welsh plug on the hole for the reverse gear shaft 1-1/4" OD The other box its 5/8" and the boxes have serial numbers on them ? Lastly I have a speedo drive cog pair but they are the reverse pitch of all the others (13 ) I have in my stash of bits, Are t hey off a 6 cylinder or a 490? Ray

My 28 has the casting date in large raise letter/numbers on the outside of the case, do yours? Letter, number, number...the last number is the last digit of the year. such as F 15 8 means June 15, 1928

Its been too long since I rebuilt a couple of '28 transmissions so don't remember the internal details. The have the speedometer cable on the opposite side from the '29 and later hence the gears are reversed.

Hi Jim, yes it has the casting numbers on it but also on the small flat at the rear of the gear box on the top where the tower bolts on is a Stamped in serial number , and Chipper thanks, the speedo drive gear set must be for a 29 then, I'll put it up for sale. Ray

Hi,
If indeed the speedo gears are 29 I would be interested.

Ray, did the numbers help you figure out what years they are?

OK next problem , assembledthe gear shafts with new bearings install for a dry run and screwed on both ends and I have a 0.150" gap between where the spigot shaft and the drive shaft slot to gether. Shoul there be a thrust washer or something there? Yes I have the spacer washer on the bearing end of the drive shaft between the spline and the bearing, Ray

There should be a thrustwasher between the clutch input shaft and the 6 splined main shaft,which would be about the thickness you've described

oK the gap measures 105 thou any one know where in Sydney I can get thrust washers ? And Jim one gear box is dated F 20 8 so a few days younger than yours ! But the second box has no cast date on it, see pic . Just the number 4? Ray
[img]http://www.shop.raycycled.com/?p=654[/img]

OK I can't get a thrust washer any where ! I've tried bearing suppliers , auto parts shops, industrial fastener supply, The filling station and Billy Possum, surely a 3/4" ID 1-1/4" OD shouldn't be hard to find ? Ray

Make your own??

They have to be hardened don't they ? Ray

Hi Raycycled,

I cant remember to tell you the truth Ray, it was so long ago. I either used the best used one I could find or a washer the came close.

Others may be able to answer if hardened or not, but would you want hardened washer up against hardened shafts, or a washer that will wear and not the shafts? You could always flame harden if required.

Good luck with the rebuild.

Cheers

Ray

As it takes the force thru the main shaft each time you disengage the clutch I think a plain washer may be too soft, but your right don't want too hard either wearing the shaft ends . Ray

I would much rather have the washer a bit too soft than too hard. If all is well lubricated there should be little to no metal to metal contact between rotating parts. Therefore any wear should be minimal considering the number of miles these old Chevys are driven.