rear gear change
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Senior User
Joined: Jun 2003
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rear gear change
I would like to know if anyone has changed the rear gearing of
F150 from a 3.55 to a 3.73. I have a 2000 F150 with the 5.4 ,
with a 3.55 LS rear. Is it possible to change to the 3.73 LS,
I was told that it could not be done because of the computer.
F150 from a 3.55 to a 3.73. I have a 2000 F150 with the 5.4 ,
with a 3.55 LS rear. Is it possible to change to the 3.73 LS,
I was told that it could not be done because of the computer.
Junior User
Joined: Jun 2003
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rear gear change
Im going through the same thing right now also. You can change your gears but will need to change your computer programming a little bit. You can buy the programmer and do it yourself pretty easy. I put a link below so you check the differences you will see with different gears. Its a pretty good web site.
http://www.mgbexperience.com/misc/tirecalc.html
This site will answer all your questions about what gears with what size tires. Its the most accurate site I have seen.
Check it out.
Ed
http://www.mgbexperience.com/misc/tirecalc.html
This site will answer all your questions about what gears with what size tires. Its the most accurate site I have seen.
Check it out.
Ed
Senior User
Joined: Jun 2003
Posts: 189
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rear gear change
I just finished having my 2002 SuperCrew 5.4 with 3.55 changed to 4:10's. I've got 285 70/R 17's and with this combination, it's perfect for towing and empty! The stock tires were 265's but Toyo just came out with the 285's in the Open Country TA's. They rock! Nice fit, nice handling, and great off road.
I had the dealership recalibrate the computer but the speedo is still off about 3 MPH at 65, so that's not too bad. I'm going to invest in a HyperTech or SupperChip so that I can tweak the computer, but they did a pretty good job. Much snappier and lot's of torque! Remember, recalibrating is not just for the speedo, it's for the tranny, fuel, etc. Very very important if you want the proper combo.
John
I had the dealership recalibrate the computer but the speedo is still off about 3 MPH at 65, so that's not too bad. I'm going to invest in a HyperTech or SupperChip so that I can tweak the computer, but they did a pretty good job. Much snappier and lot's of torque! Remember, recalibrating is not just for the speedo, it's for the tranny, fuel, etc. Very very important if you want the proper combo.
John
Senior User
Joined: Jun 2003
Posts: 292
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From: Las Vegas
rear gear change
Hey thenetguy! I have some serious questions for you...I have an Expy with a 5.4 4x4 that I just replaced the crappy 3:31 gears for 4:10's in. And guess what, now it shifts terrible. Im planning on sending my unit to Ford for the speedo calibration, but I was wondering if it would do anything else? It sounds like it did for you. Let me know your thoughts... Thanks
Senior User
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rear gear change
Yep! The recalibration will also take care of your tranny problems. The computer controls the tranny shift based on gear ratio and tire size. Having it recalibrated will clear this up for you! Mine shifts smooth with lot's of torque.
John
John
Senior User
Joined: Jun 2003
Posts: 292
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From: Las Vegas
rear gear change
Hey Thanks! Now my only fear is that I have to tell Ford about my gear change. They said that my warranty will be long gone if I mess with the gears... Oh well, I would rather have POWER.
Moderator
Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
rear gear change
The only part of the warranty that should be voided is what you have modified, such as the rearend. Everything else should still be covered.
Jimmy
Jimmy
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Senior User
Joined: Jun 2003
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From: Las Vegas
rear gear change
Just picked up my rig from Ford after having them re-program my computer,and let me tell you"WOW". It actually shifts when you get on the gas. Now I can feel my new gears...You guys were right, thanks
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Senior User
Joined: Jun 2003
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rear gear change
You're welcome! Now I'd recomend being careful to break your gears in. Go easy on them for at least 500 miles. You're not supposed to tow or haul any heavy weight. If you don't believe me, just feel your differential after you drive a bit and you'll notice the pumkins are pretty hot, hotter than usual. I've change the r&p's in quite a few rigs and this is the best way to add additional torgue. It works doesn't it?
John
Seattle
02 F-150 Super Crew Lariat, 5.4, 4:10, P285 70/R17
John
Seattle
02 F-150 Super Crew Lariat, 5.4, 4:10, P285 70/R17
Senior User
Joined: Jun 2003
Posts: 292
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From: Las Vegas
rear gear change
Yeah, Ive driven approx. 600 miles. I did take it very easy at first. I really had no choice, the trans shifted terrible, until I tookit to Ford. We took our first trip in the desert with the new gears and L/S, and I do say I was pretty happy.
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Joined: Jul 2003
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From: Idaho
I just completed a gear change on my 1998 F150 4X4 from 3.55 to 4.10. The tire size is 265/75/16's with a ride heigth of 31.6". The performance difference is great. The 98 and older models have a gear driven speedo. If you can have your computer reprogrammed for the 4.10 do it. You'll like the difference in performance.