Front end groan - suspect springs

Reprise

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#1
Ok. Finally, after fixing up the Voy during the last couple of years, I pulled the trigger and purchased a travel trailer.

Trailer:
Approx 3950 lbs dry, 25ft, coupler to bumper. Tongue weight is listed at 430-ish.
Double Axle; leaf springs. Each axle rated @ 3750
Dealer installed a WD / anti-sway hitch (overhead load bars; no chains). I did like the way it performed; trailer was solid & 'moved as one' with the Envoy.
GVWR on the trailer is about 7200, so I have room for cargo, etc.
I did not take the rig to a weigh station (no CAT scales nearby at either end of the trip)

2003 Envoy XL:
Rated for 7000 lb towing (5.3L, 4WD, 3.73). Also has a built trans, for reference (but really not a factor here)
Pulled very well - I knew I had 4000lb behind me, but no problems towing 80mi or so back home over mostly flat interstate. Kept trans in 3rd almost all the way home. The only issue was watching the iFCD appear 'stuck' in the single digits, and the fuel gauge move a bit faster than usual. But that was expected.

Last summer, I replaced the following in the front end:
OEM Shocks (w/ Bilstein HD, all 4 corners - and I really like the ride with them). New mounts, h/w, etc.
(Kept the OEM springs, which are the 'orange' (2nd stiffest), per RPO / research). A prime factor in not swapping out to 'quick struts', btw.
New upper ball joints & sway bar links (Moog, fwiw)
All suspension is stock; I'm not lifted, stock 17" wheels / tires, etc.

I did not replace the LBJ (still OK; I do have the replacement LCA assemblies, but skipped putting them in)
AFAIK, the inner / outer tie rods are still OEM. Total mileage on this 2003 is just shy of 150K.

So here's what I noticed...
- The front end felt a tiny bit light (but still very controllable). I expect to toy with the hitch adjustments a bit to adjust that, but I had no discernable sag in the rear while hooked up. Even the salesperson noticed that it sat very well. If it weren't for detecting that slight change in the front end from a driver's standpoint, I'd leave the hitch alone.

(note: I did not have house batteries (2 x 6V) loaded on the tongue (they were in the back of the Envoy, not on the trailer.)

The issue:
- When I started underway, I heard a groan (only once, and I didn't place it at the front end).
- When I dropped the trailer and drove home - after a couple of miles, I heard essentially that same groan as I was going on a slight downhill. This time, I definitely placed it at the front end, and for lack of a better analysis, figured that the front end settled back down on the springs.

Each time, I only heard that groan once. No other 'new' noises or ride degradation, suspension-wise, since last week when I towed the trailer.

I'd like to get rid of the groan, but I'd also like to not get stiffer ride than what I have now, when not towing. But I'll do what's best / needed to have optimal control, especially on the steering axle.

Thoughts? I did look on e-trailer at some helper / replacement springs, but not sure if I need them / what I need. So I figured I'd check w/ the experienced towers here.
 
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Reprise

Reprise

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#3
I didn't measure the height at either front / rear, but the rear appeared to regain stock ride height once the bars were attached. Stance looked as it usually does f/r, IMO.

The Voy has rear springs (never had the air suspension). New Bilstein HDs in the rear, but otherwise stock.
 
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Reprise

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#5
Yep - I know to do that, 'now'. I know the dealer didn't measure - at least *after* the trailer was added.

Trailer is stored at a remote site, and it's been hella cold all this week. But I'll measure pre- and post-hookup, f/r, and post back w/ results. Appreciate the quick reply.
 

Chickenhawk

Well-Known Member
#6
It may not be this simple, but sometimes a groan in the front end when both wheels travel the same amount, such as going downhill or over a dip or your trailer causing the front end to rise and fall equally on both sides, is the front sway bar bushings. If they get dry after a few years, they start to groan as the bar moves up and down. This only happens if both sides of the front end move either up or down equally because the bar then rotates within the bushings. It is especially noticeable if the bushings have ever been replaced with urethane bushings. (They require regular lube, and you have to remove them every few years to replace the lube.)

If you suspect they might be dry, drop the bracket and shoot some silicone lube in there to see if the groan disappears temporarily. If so, they should be replaced. Rubber ones wear out, and the urethane ones dry out from lack of lube. This is why we tend to avoid those colored sway bar bushings because they groan if you don't keep them greased with the supplied lube. The BEST sway bar bushings are the new thermoplastic ones from Moog, AC Delco, NAPA etc. (They are all the same part; just rebranded.) You can recognize the thermoplastic ones because they are blue. They don't require any lube at all, either at installation or down the road.

I know it seems like a little thing, but I heard a fairly loud groan from my front end only occasionally, and only when both front springs would compress or decompress at the same time. I had to get rid of my urethane bushings even though they were not worn out, and the thermoplastic ones fixed the noise permanently.
 
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Reprise

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#7
This is great info - thanks!

I will swap out the bushings, as I have the Moog replacements on hand - just never put them in (forgot about them as the truck was 100% quiet after replacing the other items last year). Hopefully I can swap them w/o having to drop the bar, as I have threadlocker on the links, along with lockwashers. I remember they have a 'slot' cut into them, so fingers crossed.
 

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