I have a '93 Dodge with a 12v Cummins and a 5-speed Getrag 360 tranny. My speedometer last week started moving all funny and it eventually stopped working all together. I got a new speed sensor for it and that didn't fix it. I was thinking that maybe the plastic speedometer gears melted or somthing and was wondering if anyone knows how to access the speedo gears. Are they inside of the tranny to where I have to disasemble it or are they somewhere else? There's another thing that is attached before the speedo sensor in the shape of an L outside of the tranny, is that what holds the gears? If I had my digital camera I'd take a picture, but it's still in the repair shop.

 

TexasBlake,

Take a look at this http://www.turbodieselregister.com/u...0&albumid=1299

I believe this is the part that you are talking about. There are two components one has the electrical connection and the other is turned by a gear from the transmission in 2 drive vehicles or the transfer case in 4x4. You will see from the pictures that the two shafts must be square at the end or else the speedo will not work. Also make sure that you clean the electrical connections and apply some dielectric grease and that the whole assembly is held snug against the tranny or transfer case.

 

The two most common causes that I have heard of for this problem are 1) loose output yoke allowing the speedo drive gear to slip on the output shaft, and 2) rounded off square drive in either the input or output of the "L" adapter.

 

You can check speed sen. by hooking a drill on the end.It will make speedo. move with key(ign.) on.Try drill in forward and rev. This will let you check wiring making sure your looking in rite place. Had same problem last week,it was little plastic gear box speed sen. hooks too. 93 dodge CUMMINS auto 4x4)

 

Okay, I'll check all that stuff tommorow. Thanks a lot.


I'm just happy the gear box isn't inside the transmission. On my Jeep's transfer case there's a ring gear around the output shaft and it turns a pinion type gear on the speedo gear. Taking apart a NP231/241 is easy for me, but I really don't want to tear into the transmission on my daily driver right now.

 

Hey Blake, it's Jeremy (aka REmy) originally from Corpus Christi. I founded WFO Racing back in the day with Philbur & Brain.
Anyways, nice to see a local on the board...

I've got the same speedo issues in my truck, tried everything the guys on this forum told me to, and still found nothing. I finally found that the "L-shaped" gear housing is bad. Its costs about $30 at the Love Chrysler/Dodge Dealer on Staples, takes about a week to get in if you give them your VIN.