New member here, not new to fords but new to the 4.9 ford world. I recently acquired a 96 regular cab shortbox 4x4 with a 4.9 and the mazda 5 speed, i will be slowly restoring this truck (sentimental value) and came from Iowa and its RUSTY! This truck is my daily driver and will be pulling trailers year round and camper during the summer, i am very fond of manual transmissions and personally feel they are better for towing/pulling. The motor has already impressed me as it pulled my dump truck home when the transmission went, but am looking to upgrade the transmission since ive been told the mazda 5 speed is a weak candidate.

 

If the transmission is in decent shape now, I would just use it as is. The Mazda 5 speed isn't all that weak. If you are going to do a lot of heavy pulling you would need more than a short box, I assume F-150 truck, anyway. Just my opinion.

 

Keep the mazda in your f150, the gearing of the zf5 sucks for daily driving and the 4.9s less than optimal hp.

 

I’ve got 2 f150s with the m5od and one with the Zf5 all with 4.9’s. The m5od’s shift better and are much more quiet. Of the three only the zf5 has required rebuild and they’ve all been used the same. The gear roll over noise the zf5 makes can be substantial and you’ll swear it’s about to grenade which I’ve been told is normal for these transmissions. Fix the plugs in the rear of the m5od top cover, change the atf regularly, don’t tow in 5th, and drive it. I don’t think you’ll hurt it with a 4.9 and f150.

 

It has a worse reputation than it deserves. As long as you keep it full of fluid and don't put a bunch of extra power through it, it will be fine. Your big problem is going to be rust. Make sure that the brake lines are solid and replace any sections that even LOOK suspect. Carefully inspect the spring shackle hangers. These are known to completely rust through before anything else does. If your spare tire is mounted underneath, take it down and clean/lube the thing so you don't have to fight with it in the middle of the night on the side of the road in the rain without any real tools handy. Also look at your oil pan and start thinking about replacing it if it's rusty. Eventually it will leak and that won't end well. This is all in addition to the normal places to look for deep rot, like cab corners, the bed, and the bottoms of the doors.

 

The best upgrade you can do I gears. So find out what you have and go from there.

 

Not true. Gears are not always an upgrade. Like a lot of things, they are a trade-off, in this case between power and gas mileage. It's true that sometimes installing lower gears will increase mileage under certain driving circumstances, but generally only when under those circumstances. It's because the transmission doesn't have to shift out of overdrive as much.

 

The variable that defines the "tradeoff" is average speed. If you spend all of your time driving in the city, mileage will be best with the tallest gears possible because it's easier to move the vehicle. If you spent all of your time on the highway, you'd want as short of gears as possible that won't lug the engine. Most people fall in between the two extremes, so that's where finding the "tradeoff" comes into play for each individual situation.

 

When it comes to these I6 1/2 tons the factory gears are almost always going to be much too tall for towing so I agree looking at what the truck has is a good suggestion.

 

I like to fall back on this thread because it was followed up on after project completion.

https://www.ford-trucks.com/forums/1...4-10-gear.html

300 with aod 3.08 and something like a 27 or 28 inch tall tire.
He went from the 3.08 to a 3.73 he had from another project and his mpg jumped from 12.5 to 15.5.
Now, you are a 4x4 so depending what gear you have currently, and how much you tow you may not need gears unless you go to bigger tires.
I suggest reading that thread, and making your decision afterwards.

 

"Tall" and "short" regarding gears might not mean the same to everyone, but the way I use the terms (and I think the way I hear them used most) would be opposite to what was said here.

"Tall" gears, like tall tires, will bring engine speed down and will help highway mileage (if you don't go too far and end up lugging). Tall gearing is also called high gearing, but comes with low numbers (3.08:1 is a high = tall gear ratio).

"Short" gears, like short tires, bring engine speed up and will make it easier to move the vehicle so around town mileage will likely improve (if you don't go too far). Short gearing is also called low gearing, but comes with higher numbers (4.56:1 is a low = short gear ratio).

 

Yeah, terms can be confusing sometimes. Higher the number shorter the gear.
I think of it as the higher the number, the shorter amount of time I spend in each transmission gear.

 

This is how I think of it, but I just had a brain fart and mixed them up.

 

my truck came from Iowa, it has A LOT of rust

 

3.55 gears