3.55's & Towing - Diesel Forum

4DMTNS · 02-04-2010, 11:15 PM

I'm looking for a 2010 SRW F350, I'd like to know how these trucks pull with the 3.55's. My '04 & '99 both had 3.73's and I am happy with them. What I need to know is do I look for an '09 with the 3.73's or go with an '10 and the 3.55's? My 5th wheel weighs in about 13k loaded.

NickBeek · 02-04-2010, 11:45 PM

Did you check out the towing specs on Ford's web site?

The only personal experience I can share with you is that my old F250 (gas 351 engine) and 3.55 gears didn't tow so great, but it had a LOT less HP and TQ then a 6.4 does and 2 less gears in the trans.....

MPD56 · 02-05-2010, 12:18 AM

4DMTNS: I have the 3.73’s and a 12K trailer, I don’t have a problem pulling it with the 6.4 and I don’t think that there would be a problem with the 3.55’s. One thing you might want to keep your eye on, is I have the 18” rims and the tires are 1” less in diameter. Also you should try posting in the Towing and Hauling Thread, you might get quicker answers. Or in the Trailer Life Forum. Helpful links below.

Towing and Hauling - Diesel Forum - TheDieselStop.com

Trailer Life Magazine Open Roads Forum: Tow Vehicles

ndmtnsledder · 02-05-2010, 01:34 AM

I have the 3.55s in my 08 F2506.4 job3. I personally really like it for what I use it for. Pulled my 7000# enclosed 25ft trailer to MT from ND last week at 80mph pushing a 40mph wind and had no issues. I know compared to our 00 F250 7.3 with 3.73 gears it does a lot better pulling our 10k skidsteer and trailer or 19k NH3 tanks.

klobear · 02-05-2010, 11:35 AM

our 09 f350 is on its second big trip through the states, pulling a 9000lb. 5th wheel. the 6.4 with 355's pulls just great. average rpms are around 1700, and it has 18" wheels. nobody can out pull it on the hills! now if I could improve the fuel mileage....

08AZF350SD · 02-05-2010, 11:57 AM

My 08 F350 has 3.55's. I do not haul anymore than about about 10K. It is the best ratio for fuel mileage. If you plan to pull 13K I would suggest a lower gear. It is a trade off. The 3.55's cruise so well at highway speeds when empty. It seems to coast forever. I feel at times it is too high geared when towing but my toyhauler is pretty light.

PagosaRob · 02-05-2010, 02:22 PM

I agree with NDMTNSLEDDER - I've had no problem with 3.55's. I've pulled 8k from KS to NM - 900 ft elevation to 5,500 - 14mpg at 68mph (1,800rpm). IMHO they are a good choice between mileage and towability.

gossamar · 02-07-2010, 10:52 PM

I tow a 11K travel trailer with my 09 with the 3.55's, and it does tow great, much better than my 04 did with the same trailer. I have been on a few long hauls and I just put the truck in tow mode, set the cruise and watch the readings on my monitor(egt, engine temp, tranny, boost) to make sure everything keeps in check. But as mentioned, the fuel mileage ranges between 7-9 depending on wind conditions.