I have a 1995 F150 5.0L engine.It has 3.55 rear end gears can I upgrade to 3.73 gears.If so would there be an improvement in low to mid range towing.

 

You'd see a little more towing power but not a radical change…

When I had a '48 F-1 it had a stock Dana 44 rear gear… 4.44 as I recall. With a stock '56 Buick 322 engine I could leave the trans in 4th gear and slowly roll thru a stop sign, turn right and never have to upshift. I could gross 10,000 lbs. (yeah I know that's a lot) with a loaded trailer hauling scrap to my local salvage yard… no problem.

I switched the rear to a Ford 9" with a 3.70 gear. Now I needed to downshift to 3rd to make that same maneuver. Now I needed to run try my little town in 3rd gear to haul a lot of weight going to the scrap yard.

Later I installed a 2.75 gear since I was traveling a lot on the highway… that rolling stop was now a 2nd gear deal… and I didn't dare haul more than 2k in my truck/trailer combo as it just didn't have enough HP to pull the load.

My point is gears can change things a lot… but don't expect miracles.

 

If I do upgrade can I just change the ring and pinion gear

 

3.55 to 3.73 is about a 5% gear reduction. Most overdrive transmissions are at least 20%, and usually closer to 30%. So that change would be about 1/6 to 1/4 of the benefit downshifting from OD to direct drive would give. Would it help? Yes. Would the small improvement be worth the cost of the gear change? Doubtful.

If you're going to pay for a gear change you might want to go farther to get more bang for the buck. 4.10 gears would be a 15% reduction. That's starting to get more significant. Or 4.56 gears would be a 28% reduction.

Then again, how often do you tow? If you tow a lot you probably want something other than a 302, so I'm guessing it's not a whole lot. As long as you have a lower gear in your trans you can get the benefit of regearing your axle for free, just by downshifting. The only place this doesn't help is starting from a dead stop when you're already in your lowest gear. But if you can get the load rolling in first you can save yourself some money just by not using your highest gear.

 

Waste of time/money. That is so little change.

Put 4.10 in

 

I agree...

When it comes to gear swaps go big or stay on the porch.

 

You can "just" change the ring and pinion, but the word "just" doesn't mean it's a small job. Figure around $1000 parts and labor, or around $300 - $400 for parts if you can set up gears yourself (and that's sort of one of those "if you have to ask you can't do it" sort of things)

 

Very true. Also, if you've set ever set up reverse cut gears before, you'd know it's much, much more involved than the rear set.

 

How much weight are you towing? What diameter tires do you have now?

I've done the equivalent to a 3.54 to 3.73 swap by changing tire sizes, & the difference was ideal for me..........but that was with a 351W.
The advantage with this is you can easily & cheaply swap back & forth to get the best option, without being locked in to just one.

For example - on a truck with your gearing, swapping from 31" to 27" tires will gain 300 rpm @ 55mph.

But if you are going to tow heavy loads/steep terrain, a tire change probably won't give you enough gain.

 

I have 1/2ton work truck with 4.10s in it and a 5.3 v8 (chevy) and it out pulls the other 1/2ton with the 5.7 v8 (chevy) but it has 3.73s. If you are going for a permanent gear change go to 4.10s, but if you want the best of both worlds I agree with Ken get a set of Steels and put some small 10 plys on them so you can easly change in the driveway after that. I haven't towed with my signature truck yet but I am interested to know how the 3.55s do, keep us posted Mtntop.