I bought a 92 w350 single wheel with a brand new getrag transmission about 4 months ago. The lady I got it from said that when they put in the new transmission they broke the speedo sending unit, and my speedo and odometer dont work. Now my question is:

I can see a little gear comming out of the transfer case and nothing is covering it I assume this is the part under the sending unit?

I just need to know where to get one at I tried searching with no luck. Thanks.

Also could this cause the anti-lock light and brake light to come on in the dash?

 

My question relates to this one. Do they make senders with different sized gears to compensate for tire size changes?

 

You can get the VSS at almost any auto parts store. Between the VSS and the transfer case there's a ratio adapter, that will have to come from Dodge. From what you describe it sounds like the ratio adapter is broken.

Mike, there are several different adapters and pinions. What tire size are you installing?

 

plus a variety of plastic gears that follow the drive worm inside on the output shaft. Mine takes a green one which I shredded by reinstalling it out of position. When I went for a new one I saw several other colours of gear on the little speedo drive shafts, which I'm told are different size or number of teeth. That's the first place I'd look if you're getting no speedo as there's no clear position marks to get these things in right.

 

Ultimately I would like to end up at a 285 or 305. Right now Im running a 265, so knowing the the factory sizing was 235(?) I could actualy be getting better milage with a proper gearing.

 

235/85-16's and 265/75-16's are so close in diameter that there's no need to change anything. They are both considered 32" tires.

 

Wanna,
My tires are 31.5s. Any idea how far off my speedo is?

Bigwhite

 

Not enough to matter.

 

Wanna,
This is gonna sound stupid, and I'm not trying to hijack this thread, but my tires are 31.5x85 or something plus some other number like R16.5..what exactly do those numbers mean?

Bigwhite

 

On inch sized tires, the first number is the diameter, second number is the width, the "R" means radial, and then 16.5 is the rim size.

 

I went through the whole speedometer thing, when I swapped engines/transmissions.

Among many unforgettable lessons was, the speedometer-drive-pin in the Getrag, itself, spins in an opposite direction to any other transmission that I have dealt with; in other words, it spins backwards.

The adapter not only adjusts for gear ratio/tire-size, but it reverses the direction of the drive-pin.

On a Getrag, you can't simply thread the cable/sender to the transmission, without the adapter, although it will screw on; to do so will cause the speedometer to only work when the truck is going backwards.

Also, for the same reason, just any old adapter that isn't a reversing adapter will not work.

I learned a lot about this when I noticed, without the adapter, my odometer rolling the miles backwards as I went forwards.

While trying to get to the bottom of the problem, I took my truck back in time about a couple hundred miles.

Actually, this might be handy, should one wish to roll the miles back before a sale.

 

I will also add this:

When I got my adapter, the internal drive-pin, the one inside the adapter, was broken.

I took the adapter apart and found that I could fashion a replacement pin from an appropriately sized Allen Wrench, as the main portion of the pin was hexagonal.

I had to file four flats to fit the square drive in the transmission and a groove for an E-clip.

I must have done a good job, as it has worked over a year without a hitch.

 

thanks for all the help guys i'll try and get it working tomorrow.

 

ditto on that pin BK, ...I couldn't buy one so did the Allen key thing too. The speedo works perfectly but my cruise control surges occasionally so I've been scratching my bald spot over that one for quite a while. Maybe that's because I didn't etch out a groove for an E-clip as you did, ....hmmmm Also when I bolted the VSS end directly on the Rag without the ratio drive it ran the speedo about 30% fast, but ahead unlike yours did.

 

On metric tires ie 275/ 60/16 the first # is tread width in mm, the second # is the % of the tread width that the side wall height is in mm, so in this case the side wall is 60% of 275 mm or 165mm tall and the 16 is wheel size in inchs.