Wrong diff gear ratio.

Reply Subscribe

Thread Tools

Search this Thread

Jun 27, 2017 | 07:41 PM

#31

djm1204

Elder User

Joined: Jul 2013

Posts: 521

Likes: 1

From: Dunnellon, Fl

If I ordered a new vehicle and it did not come the way I ordered it, I'd have them order me a new truck.

Carry on - that is all

Jun 27, 2017 | 07:59 PM

#32

rvpuller

Moderator

Joined: May 2004

Posts: 6,508

Likes: 899

From: Home Base Nebraska

Quote:

Originally Posted by djm1204

If I ordered a new vehicle and it did not come the way I ordered it, I'd have them order me a new truck.

Carry on - that is all

When I ordered mine they keep on trying to talk me out of the 4.30 gears, after signing the order sheet I told them of it showed up with the wrong gears I would refuse the truck.

Denny

Jun 28, 2017 | 07:09 AM

#33

crewzer

Logistics Pro

Joined: Apr 2000

Posts: 4,334

Likes: 306

From: Mills River

Quote:

Originally Posted by spud57

My post was to make the point the speedo does not need to be corrected for gear change. Speedo needs to be corrected for tire size change.

This would depend on the location of the vehicle speed sensor. If it's located at the transmission output shaft, then either a change to the diff gear ratio or the tire size would require a programming change. Changing both would require reprogramming for both.

If the VSS reads the rear axle (i.e., via a fixed-spec tone ring in the rear diff), then only changing the tire size would require reprogramming.

Regards,
Jim / crewzer

Jun 28, 2017 | 08:27 AM

#34

Ron94150

Postmaster

Joined: Aug 2015

Posts: 3,146

Likes: 32

From: Maryville, TN

Guys, I think you all agree on the same thing, and are debating wording. Making it confusing. For clarification of future readers doing research, can we agree that if on a late model super duty....

Gear ratio is changed, it doesn't effect the speedo, but the computer needs to be programed to correct shift points.

If tire sized is changed, the computer needs to be programmed to correct the speedo.

Jun 28, 2017 | 12:47 PM

#35

crewzer

Logistics Pro

Joined: Apr 2000

Posts: 4,334

Likes: 306

From: Mills River

Quote:

Originally Posted by Ron94150

Sounds good to me!

Regards,
Jim / crewzer

Jun 29, 2017 | 10:26 AM

#36

Campout

Thread Starter

New User

Joined: Jun 2017

Posts: 11

Likes: 0

Camp out
The Ford dealer has installed the 4.40 gears, replaced bearings and seals. They could not change factory sticker on door frame but have put a Ford sticker on door with changes made. They also flashed the computer for the gear change. There is no change to the vin as it is not required. This truck is near useless with 373 gears as it runs in the 1300 to 1500 rpm range. The 6.2 gas with 4.30 gears runs in the 1800 2000 rpm range and performs very well 60 to 70 miles mph. Tow rating is now 15000 lbs. Mistakes can happen when ordering a new vehicle. They dealer did an excellent job of rectifying my gear issue and in a timely fashion. Truck runs great Thanks for help and advice.