F150-Guy-

I recently purchased a 1998 F150 4.6L to tow my boat. The truck only had 110K miles on it so I figured the age wasn't an issue. The boat and trailer weigh about 3700 lbs. I'm noticing the the truck is having a hard time getting out of third gear when in tow. On a flat road going about 55 mph RPMs hover around 2700-3000 and it stays in third gear. I can get it in 4th but I have to get up to about 70mph and as soon as I let off the gas it shifts back to 3rd.

I'm concerned for the engine but also it's eating a lot of gas. Anyone have any ideas for me or have had the same experience?

Wannafbody

What rear end ratio? If it's a 4 speed auto 4th is an overdrive and the 4.6 isn't a torque monster so most likely Drive is the best gear.

F150-Guy-

3.08 is the ratio. It is a 4 speed auto. Thanks for the info. The only thing that concerned me was running at 3K+ RPM for extended periods of time.

king nothing

That 3.08 gear is your problem. Damn that's a tall gear

F150-Guy-

Tall gear???

smokeywren

Your 4.6L is probably a 2V. I had a 2003 F-150 SuperCrew with the 4.6L 2v and 3.55 axle. It was a gutless wonder. One trip from west Texas to Phoenix and back with a 7x14 cargo trailer convinced me to get rid of it. Even with an empty trailer it seemed to be struggling up the grades on I-10 in southeast Arizona and southwest New Mexico.


So if you decide to increase leverage by changing out the ring gear and pinion to shorter legs, don't even think about 3.55 ratio. Go for at least 3.73 and preferably 4.10. With a 4.10 rear end, then you should be able to comfortably tow a trailer that grosses up to around 6,000 pounds. Or do what I did - trade up to a 3.5L EcoBoost engine. Even with my 3.10 axle ratio, that EchoBoost engine will tow an 8,000 pound trailer across the Hill Country northwest of Austin without breaking a sweat.

smokeywren

Yeah, pickup rear axle ratios are considered "tall" up to about 3.23, then medium from 3.23 through 4.10, then "short" for anything numerically higher than 4.11, such as 4.30 and 4.88. Then "stump puller" for anything over 5.00. Yes some Ford trucks have 5.38 rear axle ratio, and some Ford motorhome chassis even have a 6.17 ratio. Now that's what I call a stump puller ratio.

PerryB

If you have a 3.08 axle and are turning close to 3000 rpm @ 55 mph then you are in SECOND gear. Definitely go to at least a 3.73

Jared Hall

Just wanted to hop off topic real quick, but i have a Ford motorhome chassis with the 6.17 and itll haul my 2012 XLT loaded with bags and the other senseless crap we take when travelling. It'd be amazing if Ford put anything above 5.00 in the F150s. Just my two cents