Ok,

I recently (about 3 weeks ago) had the speedometer gear ratio reducer go out on my pickup. The 4-sided shaft was rounded off and allowed it to free-wheel. I went to the Dodge dealership and bought a new one. I installed the new part and it fixed the problem!! Woohoo! I drove the pickup approximately 500 miles after that with no problems. All of a sudden today the speedometer started to bounce all over the place and then the Overdrive (4th gear) quite. I limped the truck to a fellow diesel enthusiasts' house, where I took off the VSS and Speedometer Gear Ratio Reducer. The VSS checked out good when I used a electric drill motor on it. The somewhat new Speedo gear ratio reducer still had 4 distinct sides to the shaft (good). I then noticed that the 4-sided shaft had some very excessive end-play (in and out)???? Hhhmmm..........this doesn't seem right? I also was able to pull out this shaft by hand by gently tugging on it. Something doesn't seem right there Next I decided to eliminate the speedo gear ratio reducer and just directly hook the VSS to the transfer case. I realize that this method will still allow overdrive.........but the speedo will be showing roughly 10mph slower than the actual speed. I ended up driving the pickup home (130 miles) with it hooked up this way. I learned that without the speedo gear ratio reducer, the pickup will only shift from 3rd to 4th once you reach approximately 45mph (true speed). This whole scenerio proved that the somewhat newly purchased (less than 500 miles on it) speedo gear ratio reducer that I purchased from the dealership failed. How did it fail?.........I'm still looking into it. Has anyone delt with a faulty one before or had repeated problems with one?

 

IIRC there are felt spacers taht act as bushings for the mini-gears inside the reducer. A little bit of end play shoudl be OK, you'd have to open it up and see if the shaft is spinning in the gear...
at 500 miles, the dealer where you bought it should warranty it out for you and give you a new one....
You might want to pull the retaining clip and inspect the drive pinion gear. I imagine if it were chewed up, that could cause a problem with the reducer....
also make sure you lube the reducer, most have a zerk fitting on them IIRC...

 

Thanks for the info! This unit is obviously sealed by 4 rivets, therefore they are not intended for the average Joe to pull apart. Now that I made it home, my plan is to compare the new reducer to the old one and see what the physical differences are. I just find it ridiculous that this part failed once again after being replaced and having less then 500 miles on it!

 

You can also buy them here,maybe a bit less money.


http://www.transmissioncenter.org/sp...e_and_jeep.htm

Bob

 

Ok guys, here is a picture explaining my troubles. Basically the new speedo gear ratio reducer stopped working. Why you ask?........... The first time I pulled it off, the 4-sided shaft was intact but it had massive end/thrust play. I was also able to very easily pull it out by hand! The old one did not allow you to do that. The only reason why the old speedo reducer failed was because the 4-sided shaft was rounded off in the center.

 

Does any speedometer shop carry the part shown below? I remember reading an old post by a 1st gen DTR member who was able to get one from a local speedo shop for less than $2.00! If I could find a replacement for the old rounded off 4-sided shaft........I could get the speedometer functioning correctly again. Sorry for such a blurry picture!

 

You could try putting a thin coat of JB Weld on the old rounded shaft, then lightly filing it square again...


I also beleive someone mentioned lightly hammering them back to square?..

 

[QUOTE=Chrisreyn;2052127
I also beleive someone mentioned lightly hammering them back to square?..[/QUOTE]

Yeah, that method is designed for the "female" recieving end of the 4-sided shaft. Mine is in good condition. I figured a good, quality speedometer/transmission shop can help me with this somewhat minor problem.

 

This ever get addressed?



My uncle brazed the rod... then used a flat file to make 'er square again. Took 10 minutes and has been that way for 100K.


Your results may vary.