I have a 99 4.0 4x4. It’s been sitting for years as it was in a bad accident and I love to procrastinate apparently.

Anyway, finally got it running again. Put a rough country lift on it with some 33’s. It has 240k miles on it though and I want to pump it up a bit. Almost a decade ago I was looking into a SOHC swap and a supercharger with a small pulley.

I’d just like to reach the 200-250 wheel HP range. Only problem is I’d still like to pull a small trailer over the sierras and don’t want to lose the manual trans or 4x4.

Just want to ask if the manual trans can take the kind of beating some low boost and extra weight would present. If not is there any way to beef the trans up?

This isn’t my only project nor is it my main one. I just want some simple bolt-ons for reliable power.

 

Well As you stated..."I love to procrastinate apparently" . With bigger tire, you will need to upgrade the front and rear gears. Manual trans don't like to tow well. Go with an automatic.

 

Welcome to the forum

1988-2011 Rangers used the M5OD-R1 manual transmission, it is rated at 330ft/lb torque

4R44E(or 5R) automatics are rated at 440ft/lb
4R55E(or 5R) are rated at 550ft/lb

You have a BW1354 Transfer case which would be good up to at least 550ft/lb, same as 4R55E automatic

All manual transmissions have lower torque rating than almost any automatic because if the "weakest link" which is the surface area of the "gears" that are driving the output shaft/drive line
Manuals just have less surface area to spread out the torque, so lower torque rating and lower towing capacity because of that

The bigger tires are a strain on the axles and differential

4.0l SOHC is rated at 207HP with 238ft/lb torque

So at 250HP you might get you another 15ft/lb so 250ft/lb, which would be fine for the M5OD-R1 and transfer case

 

I have towed many years with a manual transmission. They tow just fine, but I learned you should never tow in 5th (OD).

 

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