Transmission interlock

Beforemytime
Beforemytime Member
in HUDSON
I've already solved the problem but I learned something in the process. My new to me '38 Terraplane shifted flawlessly for the first couple hundred miles I drove it. Then it suddenly refused to go into the R or 1st positions. 2nd and 3rd were unaffected. Once I dug the rubber floor mats away and took the floor pan out to expose the transmission top I noticed the peculiar mechanism that locks the transmission into each gear unless the clutch is fully depressed. This also explains why the gear shift lever will not move when the engine is off.  
Truthfully this is the most confounding design I've ever seen, the utility of which escapes me. The linkages for the R/1 gate had become misadjusted and were not unlocking the shifting rail. Five minutes with an adjustable wrench solved my problem.
Hudson was quite innovative, I'd never seen anything like that before. 

Why were they built like this? Nobody does  today.

Curious 
David 

Comments

  • Jon B
    Jon B Administrator
    It can also be adjusted from beneath, without removing the transmission cover. Easiest to do the adjustments with someone else pressing on the clutch pedal to test the precise location of alignment.
  • durandjv
    durandjv Member
    I think they were for the electric hand. You can select the gear before pushing in the clutch, and without the interlocks it would imidiately shift.
  • Geoff
    Geoff Senior Contributor
    It's a moot point whether the interlocks were meant to stop jumping out of gear, or to ensure the clutch was fully depressed before shifting gear.
  • durandjv
    durandjv Member
    I got thinking (does not happen often) the electric hand has a switch that energizes the system only when the clutch pedal is pressed in, so my earlier comment is incorrect. Sorry.
  • Park_W
    Park_W Senior Contributor
    That shift lock arrangement was a real aid when at the Chicago drag strip with my '38 H8, years ago in the early fifties. Winding up in first, I could put pressure on the shift lever in the direction of 2nd gear, then when I was ready for 2nd, all I needed to do was a quick in and out with the clutch and I was in 2nd. Same with the 2nd - 3rd shift. Never blew a transmission or clutch, but I did have a guy who had been observing the races come up and ask how I got the Hydramatic in that '38!
  • Park_W
    Park_W Senior Contributor
    Here's the hot dragster. Took it to the Chicago area's quarter mile strip four times, won the class every time. Heavy stuff for a seventeener! src="https://openforum.hetclub.org/uploads/editor/z0/ann9nztnewwg.jpg" alt="" />

  • Beforemytime
    Beforemytime Member
    Sweet 
    Thanks for posting 

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