Available Axle Ratios - F350 Power Stroke CC SB SRW 4x4

[parfam_al]

Getting conflicting answers from local Ford dealers. Can I order a 4.10 Limited Slip axle in a new F350 Power Stroke Short Bed SRW 4x4 Crew Cab pickup? Seems that every dealer within a 100 miles of me has a different answer. Yes/No/Only a 3.55, 3.73, etc..... Looking online no help either - unless I'm blindly missing something. Help!

I'm fortunately in a position to order exactly what I want rather then buy off the lot and I can't get the same answer from local (within 100 miles) dealers. I want what I want if it is really available, not what someone is getting some extra bogey for moving this month....

Thanks, John

[lynnmor]

Originally Posted by parfam_al

Getting conflicting answers from local Ford dealers. Can I order a 4.10 Limited Slip axle in a new F350 Power Stroke Short Bed SRW 4x4 Crew Cab pickup?

I'm fortunately in a position to order exactly what I want rather then buy off the lot and I can't get the same answer from local (within 100 miles) dealers.

The salesmen know nothing, go here and build it online: https://www.ford.com/new-trucks/

The only way to get a 4.10 axle is with a dually. 3.31 comes with 18" wheels and 3.55 is with 20" wheels, both give about the same results in performance. One exception is that you can order the snow plow package and get the 3.55 with 18" wheels, that is the best for performance.

[mrgrayaz]

I fail to see how wheel size makes a difference. The overall diameter of the tires does not change.

Anyway no you can't get 4.10s on SRW and with 900+ ft/lb of torque I can't imagine why you would want them. Get the 3.55s and move on.....

[lynnmor]

Originally Posted by mrgrayaz

I fail to see how wheel size makes a difference. The overall diameter of the tires does not change.

That is not correct, the difference it the available tire sizes is almost exactly the difference in the two gear ratios available.

[jtbuilds]

We have 2016 F350KR 4x4 CC SB with 3:55.....Fantastic when towing 10,000bls but it leave something to be desired when towing 14,000lbs.....nothing left up a 8% grade and the engine brake is useless going down the same grade....wish we had 3:73 or 4:10 when towing more than 10,000lbs

[wingnut60]

The loaded radius on the 18s is 15.67"; on the 20s, either 15.9 or 16.0. Do the revolution/mile count....
When all 3 tires are that close in loaded radius, I can't believe the truck will notice what tire is on the wheel--rear end, yes; tires, no.

[4x4ord]

Originally Posted by jtbuilds

We have 2016 F350KR 4x4 CC SB with 3:55.....Fantastic when towing 10,000bls but it leave something to be desired when towing 14,000lbs.....nothing left up a 8% grade and the engine brake is useless going down the same grade....wish we had 3:73 or 4:10 when towing more than 10,000lbs

It's not a matter of needing 4.10s for trailers over 10,000 lbs. You found a hole in your gear ratio with that particular weight and hill combination. On a 6% grade the 3.55 would be a great choice for a 14000 lb trailer. A 3.55 gear ratio would also pull an 18000 lb trailer up an 8% grade better than a 4.10 axle would. For 2018 Ford recommends towing up to 21000 lbs with their 3.55 axle SRW truck.
The new Ford's have a flatter power curve which make gear ratio selection less of a concern.

[vikingboy1]

I have a 2011 full size crew cab 6.7 SRW with a 3.73 rear end and it tows 17000 no problem so far. engine brake and trailer interface works great.