i got a 93 f150 4.9l 4x4 with 3.08 gears, 31's bfg at's. right now im thinking about switching my gears on my truck to 3.55ls with a ls in the rear and a e-locker up front. but people are telling me to not put the locker up front but put it in the rear then ls up front. i would only use the locker when i go mudding not in winter driving.. and i want to lift my truck and put 35's on it but people are telling me to go with 4.11 gears but wouldnt 3.55 be good for those tires. its just like my 3.08 with my 31's right now.



and how would i get the gears out of the front axle of a truck cause the junk yard quoted me $200 for both front and rear for everything(guts, ring and pinion)?

and for the front would it be reverse cut gears i need?

what would you think about these for the rear? case then i buy a locker for just the rear then and get a ls assebly with gears for the front at the junkyard.

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Ok, to answer your first question....with that front end, unless you've done a solid-axle-swap you still have the stock Dana 44 TTB. This axle is weak in comparison to its solid-counterpart, and putting 35s on it is technically pushing the limit of what it can do with an open carrier, but many people have ran them with little problem, you just have to be careful with the skinny pedal. Once you start locking it, and you get into a bad situation where there's a bunch of torque headed to that axle and no where for it to slip, its going to break. Weather it be hubs or the actual shafts, somethings going to give. A LS carrier in that axle will be a lot better because if you do get into that bad situation, its going to let some dissipate through the slippage of the LS.

Secondly, if you want to keep this truck as a Daily Driver, I would not put in 4.11s in. With your 4.9L, the higher revs are going to put that engine outside of its powerband and you will probably see a substantial drop in mileage (3-5mpg). It will be great for stump pulling and crawling, but at highway speeds its going to be a whining machine revved that high.

To get the gears out of a front axle TTB, you have to split the housing on the drivers side, since the cover is actually the TTB arm. You slide the axles out, unbolt it, and take it out from the rear.

No you would not need reverse cut gears, those are for front and rear ends with High Pinions where the pinion is on the top half of the differential.

Those gears do look good, I see no large chips missing out of the gear teeth, and they don't look rusty, but a word of advice about using a locker in an 8.8" rear end, get a C-clip eliminator kit as well. That way, if/when you snap an axle, it at least won't fall out and leave you completely stranded.

Hope this all helps
Nick

 

(RPM*Tire inches)/(Rear gear*tranny gear*336)=MPH.......Any good at algebra, you can solve for anyone of them.

With 35" tires, a 3.48 rear gear would put you at the same ratio and driving rpms in your drive gear (1:1)...

So yea, a 3.55 would keep it the same for you. About 60mph @2000rpms in Drive (NOT OD if you have it). If you have overdrive, I think it's crazy to keep that tall of gears, but if your happy it's your truck.

Your not gonna lose 3-5mpg with 4.11s, that's rediculous. With 4.11s your only gonna go up 367 rpms at 60mph to 2367rpms total. And your powerband is NOT under 2370rpms. It actually brings you closer to your powerband.

Me personally, wouldn't go less than 4.56s with 35" tires, no less than 4.88s if I have OD. And those are only gonna bring me close to the STOCK ratio.

 

4.11's would be perfect with 35 inch tires with the 300.

I have a 4.11 gear with 31 inch tires with my 300. Like nighthawk said it's a poor combo. I can pull anything in first gear though.

 

The 300 makes low end power so it doesn't need really low gears.

 

With 35" tires and 4.56 gears... In Overdrive at 60mph:

E4OD--1870rpms

M5OD--2101rpms

'93 specs---145hp@3400; 265lbs/ft@2000rpms

Is 2K rpms too much for highways speeds? Do y'all cruise at like 1500 with that I6?

 

I'm trying to unload a set of 3.55's if you're interested.

Richmond Ring and Pinion Gear Set with install kit for Ford 8.8"

 

It does with 35 inch tires, man. It's still a six banger and needs the torque multiplication to turn over those tall, heavy tires.

I run at 2,100 RPM at 60 mph. 31 inch tires, 4.11 gear. About 2,500 to go 65 / 70. I don't like those RPM's on the highway with the 300. The 300 does best around 1,500 on the highway.

 

Aight, thanks for the clairification.

 

For a balance between fuel milage and power at highway speeds the motor should be turning at about it's TQ peak at cruising speed, so the ratio you use will be different depending how fast you like to travel combined with all the other specs like tire size, engine and trans, size of the truck, and if it will be hauling something or not. The 300 has no top end power compared to the other motors so it's easy to overgear it, 4.10's and 31's are just about perfect for the 5.0 but I think it's too much gear for the 300, 3.55's would be a better fit for most people.

 

You are correct, my Irish friend. 4.10's and 31's are a poor combo for the 300. While I may not have to downshift on the hills, I still have no passing power for the highway.

I think 4.10's and 35 inch tires would be fine, though. 35's are a big tire.

And please, let's not forget when dealing with EFI 300's, they do rev a bit more and don't have quiet the low end grunt. Just something to keep in mind when gearing the 300 for big tires.

 

I just did a quick scan on the. Thread, and didn't see anyone correct this. ALL TTB axles ARE a HIGH PINION axle. Therefore require "reverse cut" gears.


Also, 35s, no matter the (gas)engine/trans combo, I'd go 4.56s or 4.88s. But that's me.

 

Not reverse cut. Reverse spiral.

I don't think you'd want 4.88 gears with a 300 and a T-18.

At 60 MPH that would put you at 2800. At 70 you are running 3300.

Those numbers are too high. Transmission DOES make a difference.

 

Once again, we agree. The taller the tire the harder it is to turn. All about leverage!

 

Nevermind. I didn't know that, Andy!