Speed sensor help!

[Strick-9]

Alright guys, I need some help with a bad speed sensor.

The speedometer shows nearly the right speed when traveling, but often drops and becomes erratic.

I took the speed sensor out and spun it with a drill. The speedometer worked fine.

Then I stuck my finger inside the transmission and felt the helical drive gear. It is free to rotate. Is this right? It seems the drive gear should be directly attached to the driveshaft.

Before I tear into the transmission, I thought I would ask the professionals. #ad


Thanks,
Chris

'93 D250 5-speed tweaked pump

 

[Paul Herioux]

Chris,
Sounds like it is time to pull the tailshaft housing off of the trans. The gear should be keyed to the output shaft. Probably had a snap ring pop loose and allow the gear to move far enough to let the keyway drop out of the shaft. If your lucky it will be laying in the housing when you pull it.
Good luck.

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The smiling ex-dealer technician
89 w250, 47rh trans, cleaned up exhaust, Dynomax bullet muffer, 3" lift, unknown oversized injectors

 

[Gary - K7GLD]

I agree, sure seems the internal drive gear SHOULD be fixed in position, and not turn freely...

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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... Tweaked pump, upgraded radiator... MORE than a match for every new PS Ford encountered so far...

"Dura" WHAT? NOW I know where all those recycled beer cans go...

 

[Bob Beauchaine]

Hi Chris
I've posted this a couple of time but here goes again. Drop your rear drive shaft at the transmission and check the nut that holds the output shaft on the transmission. It act as a jamp nut to hold the drive gear in place. It is the only thing that keeps the drive gear from spinning freely. Lock tite it and tighten it down that should cure your problem. If you need the torque values let me know and I will dig them out. Good Luck.
Happy Trails
Bob

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1993 250 4X2 - Banks Power Pack, BD Power Injectors, K&N Air Filter, 6 gauges and tweaked pump. 27lbs boost unloaded.
Horton fan & NV4500 5 speed.

 

[Strick-9]

Bob,

Thanks for the explanation. I searched the archives before I posted and saw your previous posts, but I couldn't understand exactly what nut you were referring to. Thanks for clearing it up.

I'll tear into it either this weekend or next.

-Chris