I have a 93 f150 4x4 4.9 3.08 gears e40d im putting in 3.55 gears my brother says it wont even make a noticeable power difference but he a chevy boy lol im just asking to see if im wasting my time the truck has 31 inch tires

 

there wont be much of a difference, but youll feel a little more power. 3.08's with 31 inch tires makes the final ratio like 2.78 or 2.88. i cant remember which one. with 3.55's and 31 inch tires, i think it would be 3.35 or 3.45. which will give a little bit more power, but a little less mpg drop. if any.

 

he is VERY mistaken.
i did this swap myself with my last truck.
'96 f150 4x4 300-6/ M5sp OD/super cab/3.08's w/31" sneakers.
after the salvage yard 3.55 rear end swap,that truck came alive!
it felt like it had some nuts finally.
you WILL notice it.

however with fuel prices now,i wouldn't do it myself unless you have a use for the lower gears.
i was getting by using the f150 as a tree service truck. i needed some more nuts.it was so drastic going from 3.08's to the 3.55's that my best description was like going from a car,to a truck.that much improvement.
for a light duty,dd truck with just occasional loads/light tows,the 3.08's will work fine.but if you after some more nuts,and wont mind a little drop in FE,then don't think twice.get 'er done.

since i worked the thing into the ground,with plans of a HD diesel 4wd in my sights,it was a beat truck and not worth the effort or my $ to swap front gears.
i worked it off road in 4wd low only,to get me by.basically to get unstuck or pull tree's/logs etc.
if you want to use the truck in the winter in 4wd,then be sure to swap the front end too,or you'll end up with a limited use 4wd mismatched worthless to anyone else truck.
i didn't care.it got me by for the time being.i wasn't keeping it.
but anyway,3.08's to 3.55's.........the difference was night and day.

 

3.55's are the sweet spot for the I6, ignore the chevy guy and proceed as if he was normal.

 

Thanks alot guys I drove my buddies m5od 3.55s and it made my truck look sick but I looked up the trannys and m5od is alot lower his 2nd is my first so im alittle worried bout that is the e4od just geared to tall?

 

The M5 has 4 ratios between 1st and drive(1:1) while the E4OD only has 3 so it's not really a fair comparison. The big difference is overdrive where the auto drops down to 0.72:1 while the manual only drops down to 0.8:1, so if anything you can get away with more axle gearing than a manual truck can.

 

So there should be a noticable difference with out suffering mpg

 

Precisely. it might even get a little better mileage around town

 

How hard is it to change out the front diff,easiest way how long of a job etc

 

Changing the front diff is a lot of work but it's relatively easy work. You don't need to touch the passenger side at all but the drivers hub and side axle have to be completely removed, remove the front driveshaft, and then unbolt and drop the pumpkin from the TTB arrm. At that point you can either seperate the inner and outer portions of the passenger drive axle at the slip joint or remone the c-clip retaining the inner portion of the drive axle and haul the pumpkin out from under the truck.

 

My plan was to remove pass axle shaft at the slip yoke undo the pivot bolt let it swing down because it dont look like the rest of the axle shaft will clear the ttb arm I could be wrong