No ground on rear axle?

trouble

SDD Junior Member
Joined
Oct 19, 2009
Messages
40
Reaction score
0
Location
Cincinnati OH
Got a good one for you. Early 99 Superduty. Installed a differential temp gauge in truck awhile back and it would only work now and then when the truck was driven in the rain. Got under it to check it out and I had no ground on the rear end! Now with all those parts tying it to the frame I couldn't believe that it wasn't given a ground. I can see shocks and leaf springs with the rubber bushings and all not giving it a ground, but thought for sure it would get one through the drive shaft and tranny. Learn something new everyday.
 

DaveBen

SDD Senior Member
Joined
May 31, 2005
Messages
9,620
Reaction score
81
Location
Ukiah, California
My truck has a speed sensor on top of the rear end gear housing. It has a couple of wires, and I believe one is ground to the sensor, but not the axle. I never thought of this.

Dave :dunno
 

DaveBen

SDD Senior Member
Joined
May 31, 2005
Messages
9,620
Reaction score
81
Location
Ukiah, California
You can add Parking Brake cables to your list Kristolson. I am not understanding why the rear axle is not grounded electrically. And I mean from Ford.

Dave :dunno
 

trouble

SDD Junior Member
Joined
Oct 19, 2009
Messages
40
Reaction score
0
Location
Cincinnati OH
Yep, no ground whatsoever on my rear axle. Stuck that test light all over it. Ran one up from axle to frame. All is good now. Never would have thought though.
 

KRISTOLSON

Full Access Member
Joined
Jan 30, 2009
Messages
291
Reaction score
0
Location
Thief River Falls, MN
I guess thats why my grain trucks with electric 2 speed rears all have big ground straps from the axle to the frame. Ford probably crunched the numbers between a dedicated sensor ground wire all the way back up front and a grounding strap and saved a nickel or two.

Can you imagine the damage you could do by welding on the rear axle with a ground clamp on the frame, or vice versa? All the current trying to run through the sensor wire and the drivetrain module (for speed sensor) or whatever your temp sensor runs to? Or further? yikes. Guess thats why they teach you to put the ground on the same piece of metal if possible

on edit- assuming the sensor would have a chassis ground as well as a ground wire
 
Last edited:

trackspeeder

Stone Crusher
Joined
Apr 1, 2005
Messages
1,392
Reaction score
0
Location
North Branford CT
You can add Parking Brake cables to your list Kristolson. I am not understanding why the rear axle is not grounded electrically. And I mean from Ford.

Dave :dunno

The only electrical part on the diff is a VSS. It has its own wiring. Nothing else need electricity, so a ground is not required.
 

JLDickmon

ursus combibo
Joined
Jun 22, 2006
Messages
4,173
Reaction score
12
Location
49041
The only electrical part on the diff is a VSS. It has its own wiring. Nothing else need electricity, so a ground is not required.
a VSS is an AC pulse generator anyway.. both wires are hot AND ground

Think about it.. the rear axle is suspended in rubber bushings on the shackles and the shock absorbers. It's insulated.

I'd just take a braided strap like a chassis ground and go from a diff cover bolt to the frame.. probably right where the vent tube or drop hose for the brakes is..
 

FORDY2

SDD Junior Member
Joined
Dec 6, 2012
Messages
10
Reaction score
0
Location
Seabeck, Wa
Good to know for future reference, I would have made the mistake and asssummed, But then again my electrical skills are about the same as a 6 year old lol. No I'm not kidding.:D
 

Dogman

Full Access Member
Joined
Nov 19, 2007
Messages
1,789
Reaction score
2
Location
tampa,FL
You would think you would have a ground with the drivetrain. Everything in the trans. is steel.
 

Members online

No members online now.

Forum statistics

Threads
30,506
Messages
266,043
Members
14,623
Latest member
F350 On Track
Top