I have a 95 F250 with a 5.8 and 3.55 gears. I mainly pull a 6000 pound camper or a 5000 pound boat. I also pull a flat deck weighing up to 11000 pounds. My question is, should I keep the 3.55 gears, switch to 3.73 or 4.10's? The truck has handled all the loads I have put behind it, in most cases with the o/d off, but still does 65 mph. I'm unsure about dropping gears because the motor has a lot of miles behind it and I don't know if making it turn a bit faster would help because of the lighter stress of hurt it because of the higher RPM. Both of my diffs need work so their coming apart soon, just pre planning all the parts. Any or all thoughts welcome!

 

3.73 is one of the best all around gears.


Dropping to a lower gear will help to get the load moving easier.


Should also help to keep the load moving at a constant speed.


I see no reason to not switch if you are pulling the diff's. You will need them both.

 

What senix said. I like the 3.73's a lot. Still offers you a decent highway gear and pulling gear. If you go with something like 4.10's you will notice one hell of a change in take off power loaded or unloaded, but it sucks if you ever have to get on the highway. High RPM's, and even worse fuel economic.

 

Do you run the stock tire size? If you are on bigger rubber like some guys, you may want to go to the 4.10's.

 

I had close to the same truck that I used for work with the same motor and gears, F350 CC LB. I always hated the overall performance with the 3.55 gears, just to high for a truck that was heavy and pulled trailers. Going to 4.10s will take a lot of stress off the motor and transmission and the extra rpm won't hurt the motor, you may even be able to pull in OD after a gear change, empty you may have some hwy mpg loss but nothing durmatic. The 3.73 gears are fine for a diesel dut not for a gas motor that you want to pull anything with, the 5.8 (351 W) was a good durable motor but short on power so the lower gears would make a big difference.

If you haven't already done this replace the plastic idler pulley for the serpentine belt to steel, it may save your motor some day.

Denny

 

I'd go 3.73 and when it's time, replace the 351 with a 460. Like others have said, 4.10 gears will have you relatively screaming at modern highway speeds.

 

With a overdrive transmission you will not be screaming at hwy speeds, to change to a 460 you would have to have a parts truck so you'll have all the mounts brakets and transmission, 351W and 460 have different bolt patterns.

Denny

 

I have the ZF-5, and with 4:10s my truck is screaming at modern highway speeds. Granted, being a diesel it doesn't have the rev range of a gasser, but spinning 2500 to (barely) keep up with traffic flow (forget about places where the limit is 80) isn't ideal regardless of motor configuration, unless it's a small displacement 4 or 6. 460 parts trucks are easy to find out here, less than the cost of mods on a 351 that will never make the torque that a stock 460 will. I just feel the 5.8 is a little too small for pulling/ heavy hauling in a 3/4 or 1 ton. Great motor in the 150 or Bronco or running lightly loaded in a bigger truck.

 

So how often are you towing? To me, that would be an important consideration when it comes to making changes.

Steve

 

Here we are with a diesel guy telling a gas guy what gears to run, gas motors are coming alive when diesels fading away, that's why so many gas trucks are sitting on dealer lots with the wrong gears. I ran my 460 in my 81 at 2800 rpm all day long and it loved it, it had the same mileage at 55 or 65.

Denny

 

I'm not a diesel guy, I've owned most of the gas motors Ford has put into trucks since the 60's. I wouldn't want to turn 2800 all day with any large displacement gas motor. Noisy, hungry and not what the stock factory motors were really built for. Now, run a 5.4 at those speeds, fine. My last 5.8 wasn't happy running more than 2500 for extended periods, the mileage was dismal at anything higher than that. At that point, a 460 is getting almost the same economy (or lack thereof) with a lot more torque, allowing taller gears and more relaxed cruising.

 

Go to 4.10s, the auto transmissions have a deeper OD ratio than the manuals so highway RPMs won't be that high even with stock sized tires. I have 4.10s with 245/75r16 tires on my van and it only turns about 2200rpm at 70mph.

 

The first truck I really pulled with was a 79 F250, it came with 3.55 gears and a 351M motor, I had a motor problem after the warranty period so I changed it to a 400M (long stroke 351M). I changed the gears to 4.10 and never had any motor problems or excessive noise

Next truck I pulled with was a 81 F250 I bought well used with a 351M 3.73 gears. Built a 400M and changed the gears to 4.10 agian no excessive noise, I changed the 400 to a 460 later on with the same low noise no motor problems outcome.

Third truck was a 91 F250 460 with factory 4.10 gears but with a OD transmission, agian no excessive engine noise.

Fourth truck 2000 F350 DRW V10 4.30 gears with no problems.

Fifth truck F350 DRW 6.2 DRW 4.30 gears with no problems.

I also had more Ford work trucks over the years with all sorts of combinations.

Denny

 

I don't think there is really any reason to have a pissing contest over this. Both parties have valid points, and ultimately the exact use of the truck, and driver preference is what needs to dictate the gearing set up.

If we want to get real nit picky the area is going to have a huge influence: IE terrain, distance, stop/go, and temp. running 2,800 RPM where its 130-140 degrees is not practical either.

I thought this forum was to help people not belittle. I hated every second of running my 460 with 4.10 gears. I had to mat the truck, and run a custom exhaust to make it quite enough to make it tolerable on long drives.

If he does not drive very far, lives where its windy/hilly, wants all the pulling power in the world, or maybe just does not care about the noise he might want that.

Yes I own a diesel, but I've also owned a wide variety of vehicles as well ranging from 78-2002. 1/4 ton-2.5 ton. I set every vehicle up for what it would be used for. My 2.5 ton I didn't care if I was only moving 55 MPH tops because it was my work horse, but my little 1/4 ton was set up to run highway speeds at a low RPM.

 

My thought here is I hate exchanges like this. There is no such thing as one size fits all when it comes to towing. Terrain varies, loads vary, personal preference vary, and I suspect even what the significant other prefers in truck colors varies.

The only last word that makes sense here is "everyone is different and that's okay"! Okay?

Steve