tired 5.4....more power? cheap?
 

Just picked up a 99 f150 xlt that has 33s on it with what I'm assuming is 3" lift...has over 300k on it as far as I know...motor runs like a top..shifts perfectly...just lacks in power when taking off..wondering if there was any easy things u can do to the truck to get some more power out of it at high miles...never had a truck with bigger tires like this so for all I know its supposed to be sluggish cuz of the tires..it gets up to 60 quite fast but it won't burn the tires at all unless on dirt (example of lack of power)

Gears.

Cheap. Only $700-1000 per axle of it's a 4x4.

tired 5.4....more power? cheap?
 

X2. That's your best bet

Cool..ty both of you...sadly I'm not sure what it has in it ATM...just got it yesterday..

tired 5.4....more power? cheap?
 

More than likely 3:53

is there an easy way to check? or does it involve getting inside?
I'm totally not mechanically inclined.

tired 5.4....more power? cheap?
 

You can use your vin and a decoder. Or crawl under your truck and on the back part of your axle on the pumpkin there are metal tags coming off the blots wipe them off and post the code.

https://cimg4.ibsrv.net/gimg/www.f15...602163d781.jpg


Where are metal tags?

tired 5.4....more power? cheap?
 

Some one put on an aftermarket diff cover and didn't put the tags. :icon_mad: :thumbdown: You can check your vin and use a vin decoder.

damn..ok tyvm for the info..just google vin decoder? or ? and wont that just tell me what it came with? it wont tell me if was changed though right?

tired 5.4....more power? cheap?
 

I doubt it was changed. But yes

Do it the easy way. Look on the drivers door and find the tag there. It shows rear axle as either a 19, H9, etc type code. this gives you the stock ratio that came with the truck. If it's been changed then it is no good, but for the 99% of the trucks out there without gear changes, it will help you figure out what you have without getting dirty.

Axle Ratios for 1999 F150
Engine Transmission Standard axle ratio Optional axle ratios Notes
4.2L V6 M5R2 3.08
3.31
3.55
4.2L V6 4R70W 3.31 3.55
4.6L V8 M5R2 3.08
3.31
3.55
4.6L V8 4R70W 3.08
3.31
3.55
3.73
5.4L V8 4R70W 3.31
3.55
3.73
5.4L V8 4R100 4.10 HD Payload package

tired 5.4....more power? cheap?
 

That may not work. If there's an after market dif cover there's a chance that there is aftermarket gears installed as well.

Chock the front wheels front and back to prevent rolling. If you have a limited slip or a locker, lift both rear wheels by the axle and place on jack stands. If you have an open dif, jack one rear wheel up and place on jack stands.

If you have an open dif, rotate the wheel 20 times. Use a mark on the inside of the sidewall and a rock or block of wood or a joint in the concrete to determine how many rotations. Personally I use my phone and face it up where I can see the mark on the driveshaft and record while rotating the tire so I don't have to keep track of counting two separate rotations. Watch the video and count how many times the driveshaft rotated. Count to the nearest quarter. Then divide by 10.

For a limited slip/locker, do the same procedure but lift both tires and rotate one tire only 10 times and then divide by 10

I suck at explaining things so I'll link where I learned this info

How To Determine Differential Gear Ratio

tired 5.4....more power? cheap?
 

That's a lot of work. Chances are that 99/100 trucks have stock gears.

The tag would note if it has a locker or not, and most likely they didn't regear it, but add a locker mechanism. That is what I did, and you see a new clean cover on the rear, but nothing done to the front,, it probably hasn't had a gear change, just replaced or repaired. It is still worth seeing what was there, and you can do the once around and see if you are close to original or way off. If you are way off after rotating the tire vs driveshaft, then you better pull the rear cover and do a count if you can''t read the numbers.

tired 5.4....more power? cheap?
 

+1 what @tackle said, these motors are strong and reliable if it were my money id throw some gears in her and reap the benefits. No real point in separating the block from the heads unless your going crazy modded ya feel?

one you dont have a 5.4. Thats the 8.8 diff cover. Post your axle code that is on the vin tag on the door.

tired 5.4....more power? cheap?
 

Lol I didn't even notice that