Ford 4R70W Transmission

[Mark Gibson]

Greetings and Happy New Year Gentlemen, I hope you had a GREAT Christmas and New Year. If I offended anyone by saying Christmas, Oh well, thats what we celebrate!

Question for you on a 98 F150, 4.2 Engine 2 Wheel Drive with a 4R70W Tranny, with O/D. A few weeks ago the trans broke on me about 2 hours from home while I was on a hunting trip. The case was cracked, and they put a factory rebuilt trans back in the truck. When I was driving home, I notice that I was going past people on I-95 like they were standing still. My Speedometer was reading 70 MPH. I call the guy at the trans shop, and he said that they wouldn't have changed the speedo cable gear, and that it should be right on the money. Well, I went hunting again this weekend, and had another guy go with me in his new F150, and come to findout, my speedo is reading 15 mph slower then what I am really running....i.e. Speedo says 70, I am really running 85 mph.....not good as far as I am concerned. Can you give me any suggestions on how to fix the problem, without taking it back up the road for a 2 hour trip to the trans shop that did the job? I know it used to be the speedo cable gear that you could change to adjust your speedometer correctly......and I don't have a problem pulling the cable out, but I wouldn't know what to ask for at NAPA for a new gear. As always, your expertise is greatly appreciated!

Happy New Year

Best Regards

Mark Gibson
Jax, FL

[way2old]

Hey Mark. You can still replace the gear on the end of vehicle speed sensor. You might need to have the VIN ran through adealer to see which gear it takes. The number of teeth and size depend on the package the truck came with. Good luck. And no offence here.

[Mark Gibson]

Hi Way 2, Thanks for your reply. Is the speed sensor on these mechanical or electric? Also, if I go to my local Ford Dealer, with the VIN #, do I need to give them any info off of the tranny....ID#'s, etc? My experience with Speedo gears are that they were a nylon gear on the end of the speed o cable that you could remove pretty easily once you pulled the cable from the trans. I am not sure what I should tell the Ford Parts guy other then the truck has a rebuilt factory Trans, and the speedometer is 15 MPH off. I am assuming that the Trans shop replaced the speedo cable gear, or is the hard gear in the new trans different then the old trans was?? Thats where I am a bit lost. Again, I appreciate the advice. Best Regards

Mark Gibson
Jax, FL

[way2old]

You have an electronic speed sensor, but the gear on the end changes out same as the old style. The gear in the transmission may have different amount of teeth on it also. So call local dealer or trans shop and see if they have gear to make speedo read correctly. It is a good possibility the trans shop has the right gear.

[Mark Gibson]

Sounds like a plan.....Thanks again for the help!

MG