Chassis Flex!

stucox · May 30, 2019

So obviously im aware that the chassis rot is a huge topic on here. My chassis in my opinion seems ok, only surface rust. i may be wrong!

My question is, chassis flexing?? has anyone experienced this? whilst driving, hitting bumps and potholes etc i can see the rear tub kind shaking and moving. Not huge movements, but enough to notice.

also if i drop my tailgate down from the top there is a noticeable movement in the gap between the the rear of the cab and the bed?

am i about to join the knackered chassis gang?

2006 nav outlaw, 110,000 miles

landmannnn · May 30, 2019

Possibly, although they do move a bit by design.

freemansteve · May 30, 2019

In any case, why not go to a Nissan dealer for the free chassis check and repaint?

JDO · May 30, 2019

1. The chassis is intended to have some flex in it.

2. Both the body and tub are mounted separately to the chassis on rubber mounting blocks. They move, both relative to the chassis and to each other, especially over short, sharp bumps.

Excessive chassis flex usually manifests itself in the gap between the tub and the cab opening and closing as weight (or impact force) is applied to the vehicle. If you have a hard top or canopy, there is a tell tale bump as the top of the canopy contacts the back of the cab. However, that can also be a symptom of the canopy being mounted too far forward to account for the small, natural movement that occurs (see 2).

So unless you have some particular reason to think your chassis is rusty or snapped, if you have excessive body shake your options are to:
-ensure tyre pressures are not excessive
-ensure suspension is adequate (and not excessive) for your load - new springs may be needed if your Nav is getting on a bit
-check the condition of the rubber body block mounts, which perish and loosen with age

stucox · May 31, 2019

Many thanks to all who replied! Went to the family garage last night, put her on the pit. All looks well with chassis throughout! tank straps and mounts look good as do the leaf spring mounts etc.

So, i got brave. Hitched the tri axle car trailer on and went for a spin down the country lanes. As JDO said its the short sharp bumps that cause the shaking for sure, gentle dips in the road and off camber edges she is nice and tight and all shocks and springs acted accordingly! so this has put my mind at rest about the chassis issue.

i can assume now that the rubbers on the cab and/or the tub are knackered or the bolts are loose, i shall investigate.

Reference chassis and protection by nissan: i mistakenly sat and read basically the majority of the 5 year chassis thread yesterday lol. which made me panic and broke my heart.

my question is this, i have the facilities and help to tidy up the chassis, weld all the strengthening plates in the world on and heavily treat it after. i figured it makes sense to do whilst there is something decent to weld to.

i feel its pointless going to nissan to get a half job sealant and get messed about. i plan on keeping my truck until its ready to be buried as i love it and have poured a load of cash into it.

also its quite modified now (wheels, tryes, spacers, few suspension bits) has quite an aggressive stance, so i feel if anything was wrong they would use it against me anyway?

i may be wrong

freemansteve · May 31, 2019

You have nothing to lose by going to Nissan for the inspection....

They won't hold your mods against you - my truck is kitted with rear airbags, a 5th wheel hitch and chassis bolsters, and it was fine.

Even if they repaint the chassis, it's no more work for you in the long run, should you want to add strengthening plates. Also, any issues with getting the tub off will be found by Nissan first, and thus may make it easier for you.

landmannnn · May 31, 2019

I believe that the Nissan offer to repaint/repair is limited to 12 years, so that option probably isn't open.

Generally the tank strap is an excellent indicator, most people who have had a rusty chassis had the strap break about a year before terminal rot.

I think we are still a bit in the dark about the cause of the severe corrosion seen, if yours at 2006 is still ok then I would hazard a guess that whatever caused the problem hasn't occurred on your truck.

stucox · May 31, 2019

Think i may give them a call, as freemansteve says, have nothing to lose! Either way i plan to give the chassis some love this summer...

Without tempting fate, yes i think luckily i may have a good one. Such a shame that the whole chassis issue has to be in the back of your mind all the time.

any towing i use another vehicle, which is silly really as a pick up should be bulletproof for towing and hard work with the exception of changing clutches and brakes more often of course.

Good job they are such nice looking motors or like all the defenders ive had it would be long gone!

freemansteve · May 31, 2019

I did forget there was a time limit, but a phone call is cheap enough.

M waters · Oct 22, 2019

stucox said:
So obviously im aware that the chassis rot is a huge topic on here. My chassis in my opinion seems ok, only surface rust. i may be wrong!

My question is, chassis flexing?? has anyone experienced this? whilst driving, hitting bumps and potholes etc i can see the rear tub kind shaking and moving. Not huge movements, but enough to notice.

also if i drop my tailgate down from the top there is a noticeable movement in the gap between the the rear of the cab and the bed?

am i about to join the knackered chassis gang?

2006 nav outlaw, 110,000 miles

Realise this was few months ago but was Just reading up on your thread and just wounded if you got to bottom of this problem, as I have the exact symptoms, the bed shake the truck over every tiny bump but is fine over big potholes or speed ramps I have changed quite a few bits and it's given me a headache trying to sort it!! Chassis in brilliant condition, I striped it down plated and treated even though it looked solid. (08 ontlaw) thanks

JDO · Oct 22, 2019

The tub is bolted to the chassis, usually via some rubber or polyurethane mounting blocks. Climb underneath and check the bolts are tight and the blocks in good order.

There is always some movement of the tub and body on the chassis. Unless that movement becomes so great that they touch each other, it’s still considered normal.

Chassis Flex!

stucox

landmannnn

freemansteve

JDO

stucox

freemansteve

landmannnn

stucox

freemansteve

M waters

JDO

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