Rear sag

[rollinstone]

2014 Expy with HD tow package, 71,000 miles.

Without a load on my hitch my front end is about 7/8" to 1 1/8" higher than the rear. Is this normal? When I hook up the trailer and set up my WDH the transfer of weight to the front axle keeps the difference about the same as when unloaded. My ride is solid with or without the trailer. No obvious strut issues unless that difference in height is an indication of strut degradation.

I'm wondering if I'm due for strut replacement. But then, if my rear gets a lift up then I'm going to have to be looking at a new hitch shank to keep the trailer level on the hitch (existing shank is set as low as it can go).

 

[sjwelds]

Where are you measuring to?

 

[rollinstone]

I’m measuring from the outside edge of the wheel well/fender to a point on the vertical centerline of each tire.

 

[JasonH]

2014 Expy with HD tow package, 71,000 miles.

Without a load on my hitch my front end is about 7/8" to 1 1/8" higher than the rear. Is this normal? When I hook up the trailer and set up my WDH the transfer of weight to the front axle keeps the difference about the same as when unloaded. My ride is solid with or without the trailer. No obvious strut issues unless that difference in height is an indication of strut degradation.

I'm wondering if I'm due for strut replacement. But then, if my rear gets a lift up then I'm going to have to be looking at a new hitch shank to keep the trailer level on the hitch (existing shank is set as low as it can go).

Measure the front fender height before you load the tongue and after. It will go up after you load the tongue. When you adjust the WDH it should come back down by 50%. So if it rises by 1 inch when you load the tongue it should only rise by .5 inch once the WDH is hooked up.

If you have ride quality issues, struts may need to be replaced. They degrade slowly, so it's not always obvious when they're done. I think 100k miles is probably reasonable. Of course heavy loads and rough roads may wear them out more quickly.

 

[sjwelds]

I’m measuring from the outside edge of the wheel well/fender to a point on the vertical centerline of each tire.

Have you checked with a level on the frame? The rear fender opening on these trucks is lower than the front, is why I was asking...

 

[rollinstone]

I haven’t but I’m just taking a measurement and recording the differences.

 

[rollinstone]

Measure the front fender height before you load the tongue and after. It will go up after you load the tongue. When you adjust the WDH it should come back down by 50%. So if it rises by 1 inch when you load the tongue it should only rise by .5 inch once the WDH is hooked up.

I'm only getting about a 1/4" rise when I drop the trailer on the hitch, so as far as that goes, I guess I'm good. Just sitting there, though, whether I have a load or not, the front sits about 1 1/4" to 1 1/2" higher than the rear, which is back to my original issue.

 

[chuck s]

Tongue weight? Surprised the little trailer needs much of a WDH.

-- Chuck

 

[JasonH]

I'm only getting about a 1/4" rise when I drop the trailer on the hitch, so as far as that goes, I guess I'm good. Just sitting there, though, whether I have a load or not, the front sits about 1 1/4" to 1 1/2" higher than the rear, which is back to my original issue.

I previously recorded the fender heights on my 2017. I had the front at 36" and the rear at 35" with no load.

 

[rollinstone]

As I mentioned in the OP, the rear sag occurs whether I’m hooked up to the trailer or not. Just sitting there the rear is about 1 1/2” lower than the front. That’s the issue. FWIW, my tongue weight is about 10%-15% of total weight which is about 3400-3500 lbs.

As far as the WDH goes, I’ve towed with and without the WDH. I’ve also towed with and without a sway bar. I prefer the more solid, connected feel with the WDH. Mine also incorporates sway control and I’m glad I have it. Having towed with and without I definitely feel a difference.

 

[chuck s]

OK, the term "sag" confused me. Without knowing the heights when the truck was new 8 years ago we don't know if it's sagging or not. Right now it's just different and could be normal. If anything it may need springs, not shocks (AKA struts). But the labor involved is probably the same to replace both.

-- Chuck

 

[rollinstone]

OK, the term "sag" confused me. Without knowing the heights when the truck was new 8 years ago we don't know if it's sagging or not. Right now it's just different and could be normal. If anything it may need springs, not shocks (AKA struts). But the labor involved is probably the same to replace both.

-- Chuck

Good point re history. I bought the truck used and never really gave it much thought.

 

[GlennSullivan]

First question is do you have load leveling suspension or not. My comments below are relared to NON LOAD LEVELING SUSPENSIONS.

I have had the opportunity to measure the suspension level on my 2011 / 2014 and 2017 Expys. In all cases, I measured under the wheel wells to level ground and in all cases, when stock (see below) front to rear measured within a 1/4” of each other.

Last year, I had the local Ford dealer change the Struts / Shocks In my 2011. When I got the truck back the rear was higher than the front (opposite of your condition) And the front was bouncy. After investigation, I found the dealer used Non Ford packaged spring / shock combo units that were obviously not correct spring rates for the truck. Removing the aftermarket stuff and installing OEM Springs / Struts resolved the problem and the truck is now level.
Check your truck to see if it has OEM springs and struts at all 4 corners. If not that could be the basis of your issue.
Again my comments are only related to conventional suspension not the optional load leveling.

 

[Great BBQ]

I have a 2016 EL XLT 4x4, we use the truck to travel up and down the east coast fully loaded with out a trailer, I put a large clam shell on the roof and the back is fully loaded with me the driver and six passengers, I was getting some sag in the rear so I installed SUMO COIL SPRINGS in the rear and it helped 100%, I also seen in there videos that it helps with trailering. www.sdtrucksprings.com