I have an 02 X with the v10 and 3.73. Tires are 285/75/16, so that makes my ratio a touch taller yet.

Saturday I picked up a new 29' travel trailer with a GVW of 10,000#. Towing it virtually empty (I assume about 7500#), the X had to drop to second gear on very small rolling hills. I never towed in OD on this trip. My '95 Chevy with the 454, Banks, and 4.10's would not have come out of OD on any of these little hills that sent the X to second gear. Now, to be fair, towing it over the Grapevine (large mountain range in So Cal), it held second gear, revved up and did pretty well.

So, now I have some questions.

1) If I put the 4:30's in, I think I would see OD on flatlands no problem. I'm open to opinions.

2) If I choose to go with the 4.30's, is anything else affected? Am I missing some other mods that become necessary?

3) Is swapping gears the best way, or should I find an axle out of a wreck?

4) Is there any other application (F250, F350, etc) that has an axle that is a DIRECT replacement for the X? I'm thinking the 250's had 4.11's, but may be wrong. I'd rather go 4.10/4.11 over the 4.30 if possible.

5) If the anser to #4 is no, is there an aftermarket gear vendor that offers something in the 4.10 range for the X?

6) What am I not asking that I need to know.

7) Any referrals for good shops in the LA area (San Fernando Valley would be ideal) that could do the work?

Thanks for all of your insights. I want to make sure I do this right, if doing anything at all is the right decision.

 

I'll concur with that. I haven't done mine yet but I'm told that it is just a mechanical swap. No need for any other mod (although Kenne Bell's website says something about needing a 2 piece driveshaft w/4.30s ((we have a 1 piece)) but I think I'll call him to see what he's talking about... There is some consensus that you need the PCM reprogrammed for the gears. Wouldn't hurt I guess but the PCM doesn't need to be adjusted for the speedo to read accurately. Swap 'em out. That way you'll know the condition of the axles they are goin in. 4.11s are not available from Ford. You can get the factory gears for the Sterling axle in 3.73, 4.10 or 4.30...maybe others but I haven't checked. These are available right from the Parts Dept. However...read on... Try Randy's Ring and Pinion. How much is costs. It varies but you're probably looking around 2 grand installed. Hopefully cheaper.Sorry...can't help ya there. Try asking (if you don't get a good answer here) down in the California Chapter forum.

 

"I haven't done mine yet but I'm told that it is just a mechanical swap. No need for any other mod (although Kenne Bell's website says something about needing a 2 piece driveshaft w/4.30s ((we have a 1 piece)) but I think I'll call him to see what he's talking about... There is some consensus that you need the PCM reprogrammed for the gears. Wouldn't hurt I guess but the PCM doesn't need to be adjusted for the speedo to read accurately."
I didn't hear anything about the PCM until i read this post. Should I have had my PCM reprogrammed? If so, by who? Should the dealer have done it?

 

Go with at least 4.30's and you will never regret it (I would not even consider a 4.10 in your case) and since it is a factory option to the ECM can be easily programed to support it. Actually though with your tires size and trailer weight and hills, you might consider a 4.56 because that would give you closer to 4.30 performace with stock tires sizes vs your larger ones as I know I would.

 

it's mechanical swap. what you do have to do is reprogram the pcm so the trans knows what ratio/tire size you have. and shifts correctly.other wise it may hunt forthe gear change like mine did. took my sct excal 2 and used extrem tune to reset my ratio and tire size problem gone .

 

You don't need the PCM reprogrammed. It does not care what gear ratio is in the truck. The speed sensor reads ring gear speed and that is the same for any given speed with any gear ratio. The pinion speed changes with gear ratio, but the speed sensor doesn't read that.

 

Good point, Ford uses a "toner" ring in rear axle housing to measure speed on newer trucks, not on drive shaft which I tend to forget sometimes.

 

Is it the 10.25" or 10.5"? I'm only looking for the Ring and Pinion, right? I have the 3.73 limited slip now. Do I have to replace the axles, too?

I've never done rear end work. Can you tell?

 

No need to change axles and you can use 10.25 gears in a 10.5 housing is you use 10.25 pinion bearings. (10.25 gears are more widely availible)

 

Use the 10.5 ring gear. They are easily found. Heck, 100 of thousands of Super Dutys have been sold since 99. All wore 10.5" ring gear. So like I said, you can get them right over the counter at your local Ford Parts Dept. However, aftermarket sources, like Randy's, will probably be cheaper.

Plus, use the 3-pinion design. Your parts source will know what that is.

 

bad part is mine when hit into passing gear hunted for the up shift. after reseting the gear ratio it went away. so i do strongly feel you have to. the speedo is ok it reads off the rear. but the trans it's different needs to know

 

Not if tranny is controlled by ECM because it will have the correct data.

 

i do not want to get into it here, but the 5r110 5 spd is a different auto. trans it does need to know the rear end ratio to shift properly. MINE did not untill reset. it would hunt 3to 4 and 4 to 5 at full pedal.
here is were i got corrected myself. www.levelten.com pat and i know each other almost 30 years and he is the one that corrected me as i felt like you. sorry but i was wrong untill I WAS shown different and corrected by one of the best.
yes some get all the readings off the rear diff , some off a senser inside or bolted to the trans that senses, input and out put shaft speeds.. IN MY case I found out the hard way.

 

Ok, SCT or Hypertech? Or other? I can get the Hypertech for $287, I believe. Pros? Cons? Opinions welcomed.

Thanks.

 

I used a Hypertech to tweak a speedo on a GM truck and it worked great for that. You might try Ebay as I paid 125 for one there last year.