19' Intermittent Rough Ride (Rear Axle)

[ORTrux]

Hi All - I recently picked up a 19' Raptor w/ 30k miles (for a reasonable price given the madness in the market.) Truck is still under bumper 2 bumper and I intend on covering it with a Ford extended warranty while it's eligible.

At any rate, love the truck, however I've been trying to track down an issue where about 1/2 of the time the ride seems to go to shit. When when it's cold/been sitting, the ride is what I'd call smooth but firm - about what I'd expect from a Raptor. I test drove a couple and it feels right compared to those (and it's how it rode when I did the initial test drive.)

However, randomly after some period of driving it really seems as if the ride in the rear firms up dramatically and the truck will start getting unsettled going over rough pavement. IE, go over a pothole and you'll feel it in the front end a bit, but when the rear axle goes over it's harsher and there will be a second or two of vibration/shimmy from the rear - every now and then it'll rattle your teeth. Granted it's a live axle and this is a pickup, but it really feels like this effect comes and goes and the ride really takes a nose dive.

Long story short, I'm wondering if I've got an intermittent fault in the live valve in one of the rear shocks and one side of the rear axle is going full-firm and the axle is jumping around on one end. Worth nothing that when this is going on if I punch it from a dig it seems like the nose of the truck lifts higher on one side than the other.

So far to look into this I've:

* Put the truck up on a lift right after buying it just to give things a once over and there's no signs of major abuse that were missed - and everything looks fine. IE bump stops are unmolested, no visible oil leaking from the shocks, nothings bent etc.

* Took it in for an initial service/once-over at Ford and had them look at this - they gave the truck two thumbs up mechanically and claim it was riding normally, however they drove it in the morning, when it was cold, so its likely if this is a real thing they didn't feel it.

* Played with tire pressure. When I picked it up it was running ~42 hot and I read a lot about how on-road ride is improved by airing down to 38 hot or so in the rear. Right now it's getting up to more like 40 psi hot so I'll keep playing with this because I guess it could be the extra couple PSI as they warm up. Airing down this far definitely seemed to help some but the harshness/vibration in the rear just feels like a damping issue more than just a stiff tire to me.

* No dash warning from live valve system.

I read a couple threads on here about people having issues with Live Valve locking a shock into firm mode due to solenoid or driver failures - but usually with a dash message. It may be placebo but it seemed like switching the truck in/out of sport mode a couple times has resolved it for maybe 5-10 minutes at times. I ordered a Forscan OBD cable so I'm going to try and look at the solenoid voltages and whatnot.

At any rate - I guess what I'm looking to hear is if other people have experienced this without any error messages/codes and the best way to deal with the dealer/Ford if it is in fact occurring and it's intermittent.

 

[GCATX]

Sounds like your tires are heating up and increasing the PSI causing a ****** ride. Drop them down to 34f/32r cold and try it.

 

[ORTrux]

Sounds like your tires are heating up and increasing the PSI causing a ****** ride. Drop them down to 34f/32r cold and try it.

The effect is pretty dramatic and it's done it when they're reporting ~38 in the rear as well. Will drop it some more today though and give it a go.

 

[GCATX]

The effect is pretty dramatic and it's done it when they're reporting ~38 in the rear as well. Will drop it some more today though and give it a go.

Hopefully that will help. I think mine are around 31 cold on the rear. But I have dumb shocks.

 

[Donmatteo]

I have a 19 and anything over 38/39 it runs like crap.

I am 31 cold and 37 warm

It's possible your live shocks are getting a fault and failing to the hard setting. I thought someone else here had an issue with it not being level and a shock was throwing a fault.

 

[ORTrux]

So I aired down more, it helps, for sure, but it's helping smooth out the road surface, like small imperfections/bumps - I still think there might be something going on when it hits a bump that's big enough to really move the wheel/tire - first few minutes of driving after pulling out it rides like a dream and 10-15 minutes later there's a lot more feedback, regardless of tire pressure (checking the tires with a needle gauge and no appreciable change.)

Been doing some more reading and it sounds like there's a rash of people out there that are experiencing issues with the VDM module doing weird stuff, IE: https://www.fordraptorforum.com/threads/ssm-47757-harsh-ride-quality.70540/page-4#post-1500883

Forscan cable comes into tomorrow and going to take a look at ride height sensors and pull codes. Still a possibility I'm just imagining this but I'm 90% sure it feels better when it's cold - and given that the suspension is the crux of the truck in the first place, want to make sure I'm getting what I paid for.

Edit: Sounds like Forscan just added the VDM recalibration process so depending on what I'm seeing in there might give this a go - https://www.fordraptorforum.com/threads/deaver-eibach-combo.77943/page-23#post-1614688

 

[Swaddict]

did you try a live valve reset?

 

[Donmatteo]

10-15 minutes later there's a lot more feedback

I'm wondering if you might some unknown mods on your truck. Has Ford looked at it?

 

[Steeven Rosenberg]

I had a similar experience after picking up a 2020 a few weeks ago, but not as dramatic as you describe, so we could have very different issues, but I will share what solved the issue for me after the basic troubleshootings you also went through. I got cought in a bad storm, and switched to 4A. The ride suddenly was amazing. I could not believe it. The raptor was like a tank on rails. Never felt so safe and confortable in pouring rain (I’m in SW Florida). The next day I kept driving in 4A, and after some research, decided to stay in 4A, even when dry. The ride has been just amazing. No issues. In the meantime I’m waiting for deavers on back order which from I’ve read is the ultimate solution for wheel hop and bed sway over those bumps. Hope it helps.

 

[ORTrux]

So OBD2 adapter arrived and I hooked up Forscan. Ride height on the left sensor does seem lower than the right side, by say 5-10mm accounting for road crowning but otherwise it's reporting normally (solenoid amps ~1.6a in normal mode etc.) Doesn't seem like enough of anything to cause major ride issues.

I'm now running around ~36 hot in the rear and 37 up front. Airing down helped but there's one stretch of road next to my place with some cracked pavement that I sort of use as a canary and it still gives the truck fits - I drove another LV Raptor on the same stretch and just don't remember it being nearly as harsh.

If the solenoids are doing their thing then moving down the line I'm wondering if the valve itself is sticking inside the shock body. IE, if they're starting out in normal position when cold, then after some cycles of the solenoid stiffening the valve over bumps, if one of them isn't properly returning to an open position once the assembly gets some heat in it. This would make a ton of sense but unfortunately the valves don't have an actual position PID so that's hard to prove. Moving on from that then I guess it's general shock mechanical issues - gas pressure, worn out valve stack, sticking shaft etc. A problem for the dealer if so, but hoping to present them something concrete, may just ask for a tech ride along.

I sort of go between it just being extra ****** pavement and it being a truck with suspension built for high speed off-roading, not an E class, but then it'll really act up for a period of time and I'm back to thinking something is off.

I had a similar experience after picking up a 2020 a few weeks ago, but not as dramatic as you describe, so we could have very different issues, but I will share what solved the issue for me after the basic troubleshootings you also went through. I got cought in a bad storm, and switched to 4A. The ride suddenly was amazing. I could not believe it. The raptor was like a tank on rails. Never felt so safe and confortable in pouring rain (I’m in SW Florida). The next day I kept driving in 4A, and after some research, decided to stay in 4A, even when dry. The ride has been just amazing. No issues. In the meantime I’m waiting for deavers on back order which from I’ve read is the ultimate solution for wheel hop and bed sway over those bumps. Hope it helps.

Funny you mention it, I thought going into 4A made a difference as well but wrote that off as placebo. Mechanically it doesn't make a ton of sense - the only thing switching into 4A does if you're just cruising down a road with full traction and not leaning into the power is engage the hubs and spin up the CV's and stub axle - progressively clutching in power at various times. Curious if the VDM does anything when shifting into a 4x4 mode, I doubt it, but I'll take a look.