Gears
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Gears
This week I am having 4:10 gears installed on my 94 F-150 XCab 2WD 4.9 with 31X10.5X15 tires.I decided on the 4:10 gears with the intentions of 33X12.5X15 tires in the future. Does anyone know of any problems I may have with the computer, speedometer, or performance. Any help would be appericated.
Thanks
Kevin
Thanks
Kevin
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Gears
KC , I have a 90 F150 W 4.9L / M5OD Trans / 3.08 Gears w 31.10.5 15 tires. I had to change the speedo gear with the larger tires. Ford has several that are all color coded . I cant recall the formula that the number of teeth on the speedo gear changes the reading on the speedometer ? First make sure your speedo is reading accurate now ...when I went to bigger tires , it thru mine off considerably . I had 2 run ins w a **** Speed Cop that claimed his darling radar was the word of god . The Ford Parts guy can help you with the gear that will get you pretty close to an accurate speed on the speedometer. I think That as you add a gear w more teeth , it will show you moving faster than you actually are ??? If I recall correctly , I have a gear w 18 teeth ? Its been awhile since Ive messed w this so get the goods from someone that deals w it all the time . Im sure shops that deal w wheel / tire and suspension upgrades can tell you accurately.
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hey Kevin, if you have a 94 f150, then you probably have an 8.8 rear-end, and if so, then look under the truck at the front of the rear-end where the pinion goes in, and on the right-hand side, look to see if there is a wiring harness plugged into the rear-end, if so, that is a magnetic pick-up, and it has a sprocket mounted on the inside of the rear-end that is read by revolutions by the magnetic pick-up, so, you will not have to change a thing, because the truck will compensate for the gear change. i have a 95 f150, and i changed to a 3.73 from a 3.08, and i didn't change a thing, because the speedometer reads from the rear-end now, instead from being mounted on the tailshaft of the tranny. hope this helped, good luck.
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Rc ,
That gear pressed on the ring gear of the rear end is the the excitor ring for the anti lock brakes ... It has zero do do with the speedometer .Any other Ford drivers and or Techs can back me up on this if you think Im wrong . As far as I know , Speedos on all vehicles are still read from the trans because it is always a constant speed ...rear ends vary their speeds just by the nature of their design ...Rc its a good thing you have a Ford , any other vehicle would have hurt you by now .
Paul
That gear pressed on the ring gear of the rear end is the the excitor ring for the anti lock brakes ... It has zero do do with the speedometer .Any other Ford drivers and or Techs can back me up on this if you think Im wrong . As far as I know , Speedos on all vehicles are still read from the trans because it is always a constant speed ...rear ends vary their speeds just by the nature of their design ...Rc its a good thing you have a Ford , any other vehicle would have hurt you by now .
Paul
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well, paul, don't really know where the H**L you came from, but when i had my ring and pinion replaced, i did nothing to the tranny, explain that one. the guy that installed my gear at a rear-end shop said that i do nt have to do a thing, because the rear-end has a "sprocket" mounted on the back side of the ring gear, with teeth all over it. where the speedometer would have gone in the tranny, it is plugged, from the factory. so, in turn, maybe you need to read up on them a little more because if you are going to correct someone, maybe you shouldn't be such a smart***. i.e. owning other vehicles other than fords, if you want to have a contest of brains, then i suggest you go home and brush up on your reading!!!
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Sorry Rc , Ive been turning wrenches on Fords for sometime ... I was replying to the original post by KC . I know for a fact that the gear you referred to , that is pressed on the ring gear and the little magnetic sensor is strictly for the anti lock brakes . What someone told you and what is reality are two different things . Ask another ASE Ford Tech if you think I have posted this or previous in error ... I welcome all inputs and will always acknowledge if I have made a mistake . I didnt mean to get you all upset ...I was trying to be humourous ... You got to have a thicker skin if I can get all you all ruffled on a message board ,
Paul
Paul
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well, if i am wrong, i will admit it also, but why is it that i did nothing to anything in the tranny, and the speedometer still reads the same? it is an anti-lock brake sensor, but isn't the anti-lock brakes work off of the rear-end tire speed? and if so, then the sensor must supply speed sensing to the computer/dash, because the mazda 5spd. that i currently have is not electronically controlled in any way, i have had it out twice, no electric connections. so that would ead to the fact that speed is determined from the rear axle speed and rotation?
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Ok Rc ,
We are talking two different animals here .Say we start w a stock truck and add bigger tires and rims . Then the trans speedo gear will have to change to reflect the changes made w the tires . A larger tire rim combo will throw the speedometer off . This is where the speedometer gets its info .The output shaft of any tranny has a gear on it that turns a gear on the speedometer cable that we see in Mph . Changing the rear end gears will not effect what we see on the speedometer because the tranny is still sending the same info to the speedometer . All I was saying was that toothed ring on the ring gear is for the magnetic sensor to pick up rear wheel speed from the rear end ...thats the crudest form of Abs . Ford has used it on the trucks for some time . It relays no info to the engine EEC , The Abs has its own computer to deal w its function . Two seperate units , two totally different deals
Paul
We are talking two different animals here .Say we start w a stock truck and add bigger tires and rims . Then the trans speedo gear will have to change to reflect the changes made w the tires . A larger tire rim combo will throw the speedometer off . This is where the speedometer gets its info .The output shaft of any tranny has a gear on it that turns a gear on the speedometer cable that we see in Mph . Changing the rear end gears will not effect what we see on the speedometer because the tranny is still sending the same info to the speedometer . All I was saying was that toothed ring on the ring gear is for the magnetic sensor to pick up rear wheel speed from the rear end ...thats the crudest form of Abs . Ford has used it on the trucks for some time . It relays no info to the engine EEC , The Abs has its own computer to deal w its function . Two seperate units , two totally different deals
Paul
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so, you are saying that i have some form of a sensor or a gear inside my transmission that is sending some form of a signal to my dash? the only wires leading from my transmission were for the back-up light switch, and that is all. Ford trucks speed sensor cuts the truck off at 100? where is the computer getting its signal from to shut the truck off? you did state that the sprocket was for to read rear end speed, correct?
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Rc...
The Speedometer cable leads from the output shaft of the tranny directly to the speedometer ...it had a gear on it that is driven by a gear on the output shaft . Its a cable , no electric wires ... Ive never driven my F150 4x4 to 100 mph ..its a 300 6 ...It is lucky to run 70 on the interstate. If you doubt what Im saying , get a manual , crawl under your truck and look around or ask anyone else that visits here ....me speeky the truth .
Paul
The Speedometer cable leads from the output shaft of the tranny directly to the speedometer ...it had a gear on it that is driven by a gear on the output shaft . Its a cable , no electric wires ... Ive never driven my F150 4x4 to 100 mph ..its a 300 6 ...It is lucky to run 70 on the interstate. If you doubt what Im saying , get a manual , crawl under your truck and look around or ask anyone else that visits here ....me speeky the truth .
Paul
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lastly, i promise that there is no speedo gear going to my tranny, whatsoever. my truck is a 95 f150 with a 5spd. manual, tomorrow, you check this out, i guarantee that there is nothing there. again, i have had my tranny out twice, and i have never unscrewed, unbolted, pulled out, or disconnected anything on my tranny that had a gear on the end if it, honest. then ask them where the 95 truck gets its readings from for the speedo, and let me know. i have looked, and i did find it odd that it did not have a gear, bt o the tailshaft on the driver's side, there is a plug and a threaded hole where it probably did go years ago, but since then, have changed it over to something different.
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Gears
OK guys....
I don't know what i'm getting into here...but I have to side with R.C. I have the FORD Body and Chassis Shop Manual for my truck, a 96'. On page 13-01-8 it reads "The programmable electronic analog speedometer receives its input from the anti-lock brake sensor..." Nuff' said. In 92' Ford changed to the electronic speedo/odo cluster. The 92'-96' trucks pick up the speedo information and the ABS info from the rear diff. If you have a 92' or later F series (F150 to 350) you DO NOT have to change a thing when the rear gears are swapped. The 87' to 91' Ford pickups have the sensor in the 8.8" rear for ABS. The 87' to 91'' trucks also have a gear in the tranny for the speedo. BUT I have a 96' and the only wire on the tranny is for the backup lights. On the 87' to 91' trucks you are right, Paul, but things changed in '92.
-Hank
I don't know what i'm getting into here...but I have to side with R.C. I have the FORD Body and Chassis Shop Manual for my truck, a 96'. On page 13-01-8 it reads "The programmable electronic analog speedometer receives its input from the anti-lock brake sensor..." Nuff' said. In 92' Ford changed to the electronic speedo/odo cluster. The 92'-96' trucks pick up the speedo information and the ABS info from the rear diff. If you have a 92' or later F series (F150 to 350) you DO NOT have to change a thing when the rear gears are swapped. The 87' to 91' Ford pickups have the sensor in the 8.8" rear for ABS. The 87' to 91'' trucks also have a gear in the tranny for the speedo. BUT I have a 96' and the only wire on the tranny is for the backup lights. On the 87' to 91' trucks you are right, Paul, but things changed in '92.
-Hank
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well hank, thanks, that s music to my ears. i replaced the 3.08, and went with a ford motorsports 3.73 and a ford motorsports trac-lok, i wanted to stay with all ford parts. the whole set-up cost me $650.00 here at a place called Parson's differintial "proctologist to the cars". he has been doing rear-ends for 10 years, and he did a great job. i have sent several people to him, and not one complaint yet. the difference was on the way there, @2000 rpm in od, i was going a little over 70, now at 2000rpm, i am traveling at 62 or 63 mph. I race mine, so my quarter mile time went from 16.7 to a 16.2. the rear-end was the first thing i did to my truck. now i am down to a 15.2 in the quarter, so close to 14's, can't stop now. well, thanks hank for the support, i appreciate it. take care, any more questions, let me know.
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hey hank, i forgot to ask, i have heard that the ford/mazdafive speed that we have are junk, what do you think? i just hit 60k, and have slave cylinder and master cylinder problems, but so far, that is it. i have researched, and if my tranny does go ou, i am going to fit a fit a Tremec TKO into my truck, they make parts where it will work, but around $2000 for the tranny, where $1600 to $1800 for the mazda to rebuild, and for $2000, you will have a much stronger tranny. just wanted to hear your two cents, just curious. an automatic would probably be cheaper, but i like driving my 5speed.