FJ40 speedometer drive gear sliding past driven, why?

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Hello all. IDK if I'm missing a part, manual shows only the spacer and drive gear go on the shaft. When I install the driven gear shaft assembly into the speedo housing, while spinning it CW, the speedo gear (as can be seen by the thing turning) spins. But rotate the shaft CCW (ie. reverse), the drive gear spins out, clear of the driven, and disengages. It does not catch the threads when spun CW again, no more speedometer. I've had this apart several times over the years, might have lost something along the way. Does it look like something is missing or installed wrong? Pic 1. pic inside shaft hole after drive gear has spun out. Pic.2. spacer and drive gear, after housing removed. Pic. 3. driven gear assembly. Any input would be appreciated.
IMG_1070.JPG


IMG_1074.JPG


IMG_1078.JPG
 

EWheeler

4 Cruisers, No Garage !
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No one has had this happen?
No. It does not look like you are missing anything from the photo provided. This is what my t-case output shaft looked like when I removed the parking brake and speedo housing recently.

IMG_2686.jpg


What does the male end your parking brake drum look like? I am thinking this is what should keep this speedo gear where it should be.
 

pbgbottle

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The drive gear should stay in place once you slide the ebrake drum on and torque it up. What’s the tooth count on that speedo gear? Looks small in diameter doesn’t look like any parts are missing other than the drum to hold it all in place.
 
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I had a feeling that once I posted this, it would come back to haunt me. Yes, the drum keeps it in place, so stupid! I haven't had the speedo work in forever, thought I was onto something here, but again, the obvious presents itself, as I'm accustomed to. It was in fact a new gear I installed when rebuilding that shaft, time to figure out exactly what I have on there, apparantly the gear sliding is not my problem.
Sorry to be such a boob!
 

EWheeler

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I had a feeling that once I posted this, it would come back to haunt me. Yes, the drum keeps it in place, so stupid! I haven't had the speedo work in forever, thought I was onto something here, but again, the obvious presents itself, as I'm accustomed to. It was in fact a new gear I installed when rebuilding that shaft, time to figure out exactly what I have on there, apparantly the gear sliding is not my problem.
Sorry to be such a boob!
I dunno, that plastic speedo gear looks exactly like the one that I have. Have you ever removed the speedo cable from the cluster? If so, it is possible you didn't get the cable re-installed properly to drive the speedo mechanism in the cluster. Its a real bear to get that cable back into proper place if you have normal adult sized hands.
 
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Yea, done that and it's tight. currently running a Dakota digital dash. The output of the speedo housing spins a sending unit to the main computer. On my second one. I've come to realize that when the steering wheel starts walking around, that's 45mph, when it planes out, that's 50, and when the bikini top is full balloon, pushing 60. Maybe it's just that simple.
 

pbgbottle

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for some fun reading here is a thread I posted some info About Speedo part numbers and such.back in 2006

 

pbgbottle

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Or here more Speedo tech.

 

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