CriticalCommonBody & Rust

Jeep Wrangler: TJ frame rot at rear lower control arm mounts and skid plate crossmember

TJ frame rot at rear lower control arm mounts and skid plate crossmember is a common body & rust fault on the Jeep Wrangler on the 1997–2006 cars, and we rate it critical. Putting it right costs $1,500 to $12,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 24 documented faults on the Jeep Wrangler.

Vehicle: Jeep Wrangler
Years: 1997–2006
System: Body & Rust

This page covers the Jeep Wrangler as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Jeep Wrangler faults24 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Transfer case or Chassis and structural rust yet. We would rather show none than show a picture of a different part.

What goes wrong

The TJ chassis rusts from the inside out, and the first places to rot are the rear lower control arm mounts, the frame around the transmission and transfer case skid plate, and the central body mounts. These brackets carry the rear axle, so severe rot can let a control arm tear free and cause loss of control. Surface rust is normal, but soft or holed steel at the mounts means patch welding or a frame replacement. There was no recall for the TJ frame.

What you would notice

Flaking or bubbling rust on the frame near the rear suspension arms
Clunk from the rear over bumps
Rear of the Jeep steering itself or wandering
Fresh underseal or thick paint only on certain frame areas

How to check it

Where to look. Frame rails under the car: rear lower control arm brackets, transmission skid plate crossmember mounts, and central body mounts

Kneel at each side of the car and use a phone torch to look along the frame rails, especially where the rear lower control arms bolt to the frame just in front of the rear wheels, and where the gearbox skid plate bolts to the frame under the middle of the car. Press firmly with a screwdriver or car key on these mounts; steel should be hard, not flaky or soft. Put a finger in the holes in the side of the frame and feel for loose scale. Be wary of fresh underseal or thick black paint on the frame, which can hide rot. Ask whether any frame repairs have been done and by whom. If a workshop inspection is possible: have the car on a hoist, wire brush the mounts, and tap the rails with a hammer to find soft spots; ask the workshop to judge whether the frame is repairable.

Parts involved: Transfer case, Chassis and structural rust.

What it costs to put right

$1,500 to $12,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the frame ever been repaired or plated?”
“Has the car spent time near the beach or in snow country?”
“Has it been underseal-coated, and when?”

Now check the Jeep Wrangler you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

WranglerTJForum: What should I look for when buying a used Wrangler TJ? (sticky)
WranglerTJForum: Control arm bracket rust
Quadratec: How to Repair Wrangler Lower Rear Trail Arm Mount
Black Dog Mods: Jeep Wrangler Frame Rust Repair, TJ and JK spots

Jeep Wrangler buyer questions

Is tj frame rot at rear lower control arm mounts and skid plate crossmember serious on a Jeep Wrangler?

We rate it critical and common on the Jeep Wrangler. The TJ chassis rusts from the inside out, and the first places to rot are the rear lower control arm mounts, the frame around the transmission and transfer case skid plate, and the central body mounts. These brackets carry the rear axle, so severe rot can let a control arm tear free and cause loss of control. Surface rust is normal, but soft or holed steel at the mounts means patch welding or a frame replacement. There was no recall for the TJ frame.

How much does it cost to fix on a Jeep Wrangler?

$1,500 to $12,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Jeep Wrangler years are affected?

Our research records this fault on the 1997–2006 Jeep Wrangler. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.