I need the gear that goes on the end of the speedometer cable on a 75' F250 with a 203 transfer-case. The square hole inside the gear is round. I called all the parts stores in town and they all say they can't get one. I think they can but just don't know how. Does anyone have a part number or know where to get one. Thanks.

 

Your best bet would be to try your local Ford dealer. I have found these gears to be a dealer only item. You should take your old gear with you for comparison. The part number depends on a number of variables such as rear axle ratio, original tire size, transmission type etc. Make certain that the "snout" is the same length and diameter and that the tooth count is the same. The tooth count is usually molded into the end of the gear, ie "16 T". Also compare the direction of the teeth, whether they curve to the right or left as you look at the gear. Different gears used to be made from different color plastic. I do not know if the replacement gears follow suit. I would be glad to check local sources (Portland, Oregon) if you don't have any luck. Hope this helps.

 

I checked with Ford and they told me that they didn't think they could get it. They did find a way to order a tan one with 19 teeth which is what mine is. They want $10.00 to order it and tell me that there is no return on special order. They don't know how long the snout or which way the teeth go so it might be right might be wrong. Seems strange that they cannot look up parts for a 75' anymore. Makes me think twice about my plans to keep my 96' until 2025.

My only other hope here is a local gear and drive-line shop that said they have a box of old parts and he thinks there is some used drive gears in it. I hope to make it in there tomorrow but they have very short hours on Saturday so it may be Monday. If they have one with a different teeth count will it fit? I know the speedometer will be off but at least it will work. I am thinking that whatever drives this gear may not take well to another tooth count but don't know for sure.

From the owners manual in the glovebox it seems that the axle is a 373 ratio (only one for a 360 F250)and it came with 9.50X16.5 tires. The transmission is a auto and it has a 203 transfer-case. I am planning on changing the transfer-case to a 205 I have in the future but want to put the 203 in the truck I take the 205 out of so I want to get it fixed one way or another.

 

From my experience I would think that the gear the dealer can get is the correct gear, tan and 19 teeth. I have never seen different factory gears with the same color. Using a gear with a different tooth count will cause your speedometer to read incorrectly, either too fast or too slow. I have changed speedometer gears to compensate for tire size changes and rear end gear swaps. When you change transfer cases you may encounter the same problem, if the drive gear in the new transfer case has a different tooth count than the drive gear in the original transfer case.
On a seperate note, I would be looking into why the original gear went bad. With the rounded out hole there is a possibility that the speedometer cable might be in a bind of some sort. You might want to check that out before installing a new gear. Good luck.

 

The '65-'72 Car catalog shows only one 19 tooth tan gear, part no. C7VY-17271-A. The illustration shows the gear to be 1/2-3/4" long, with a narrow shank at one end about the same length as the gear. If you have a little time, I can check the '73-'79 truck catalog this week.

Just to make sure we're on the same page, the driven gear is the one on the end of the cable. Your topic says drive gear, which may confuse the parts guy at the dealership.

 

Thanks for the good information. I will order the gear from Ford on Monday.

The reason the gear went bad was because the speedometer cable was against the exhaust pipe under the cab. It had melted the outer plastic on the cable letting in the elements. The truck had been sitting for about ten years before I picked it up. Over the years the cable had rusted to the inner lining since there was not any outer shield on it to protect it. It took a 1/2" drill to break the cable loose. That little square hole in the plastic gear couldn't take the stress. I have a new cable to install when I get the gear.

As far as when I change transfer cases does the 205 take the same speedometer gears as the 203?

 

Yes it is the driven gear not the drive gear I just am not that technical thanks for straightening me out.

I was just looking through the owners manual on the 76' and it seems to have the same 3:73 as the 75' so I am thinking everything will be right on when I swap transfer cases. Looking at the owner manual for both it seems that about everything came with 3:73's back then. I am going to look under both of them and see if I can find any tags on the differential to be sure and also jack up a corner on both and count the drive line revolutions with one revolution of the tire to make sure they are the same.

 

Well I pulled the gear out of the 76' and it was a 20t hmmmm. Seems as though the 76' has 3.73's and the 75 has 4.10 in the rear and 4.09 in the front some sort of special order I guess???

I took the tan 19t gear to the dealer today and talked to a different parts guy than the one I spoke with on the phone. He headed upstairs and came back with a pink 19t gear. Seems as though 28 years had turned my pink gear tan. So for $8.20 I now have a working speedometer. Thanks for the replies.