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Re: '53 6400 series two speed firewall mounted con
Posted by Gary-=Miss on August 11, 2003 at 18:11:21 from (18.104.22.168):
In Reply to: '53 6400 series two speed firewall mounted control posted by Randy in IL on August 11, 2003 at 14:50:00:
Are you ready? I had to really work on my memory on this. The 1953 two speed is spring loaded to the low side and must have vacuum to go to high. This is the reason you never park one in the high side because it will slip into neutral when the vacuum leaks down and head down the nearest hill.The valve under the dash connects the vacuum to the two speed and also shifts the speedometer transmission. Th vacuunm diapragm pulls against a spring in the rear end, but, the rear end won't shift until the pressure is removed. That's the reason you shift the valve, the vacuunm diapragm shifts, then, you let up on the gas and the shift is completed. When downshifting, you shift the valve, wait a moment (sometimes vacuum is a little slow), let up on the gas just a mite to take the load off, then, go back down with the gas to synchronize the pinion with the ring gear (the planetaries). The later models used vacuum to go both ways. That stopped the problem of having to look for your truck.
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