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Article by: RobRed

Applicable Models: 100 Series (1998-2007)

Last Updated: Monday, March 28, 2016

One of the complaints most often heard is the Land Cruiser’s dreaded driveline “thunk”. Endless forum posts about the cause and remediation of this phenomenon. Most often this issue is attributed to the lubrication of the drive shaft yokes – “squirt some fresh grease in there and she’ll be good as new” I’ve heard. Problem is – that isn’t the problem, it’s only a fraction of the source. After you have lubed the driveline the “thunk” returns in a few short miles. So What is the problem you ask? Answer: Several things including the lubrication of the yokes as a small part. What the real overarching cause to the “thunk” is multiple systems worn or out of spec. This is why no one solution has been the catch all. Sure a few people lube the yokes and it’s fixed but that is a tiny tiny minority.

So what’s wrong then? One significant wear components on high mileage Land Cruisers are the suspension rubber components. Sway bar bushings, shock mount bushings, Spring perch damper rings, end links, front and rear control arm / link bushings. Both age and mileage contribute to less than optimal performance from these systems. It’s worth refreshing these systems for improved comfort, safety and to reduce the dreaded “thunk”.

Start with the basics. Lube the driveline. Next refresh the anti roll bar (sway) rubber components including the frame mounted and end link rubber components. This alone will start you down the road to “thunk” free bliss. But the biggest culprit in the fight against the thunk are the rear control links. The rubber bushings in the ends of these links disintegrates over the years and tend to elongate causing play between the mounting point on the frame and the rear axle. As you accelerate (particularly from a stop) the slack from these worn components is taken up and you guessed it – “thunk”.

Toyota doesn’t offer replacement bushings for the 100 series control links, you have to purchase the entire link. Some folks have cobbled together solutions from other Toyotas to fit the links. There are some aftermarket bushings (Superpro) that can be pressed into your stock links. Really I think the best solution is the Metal Tech 4×4 control links. These are slightly LESS expensive that the stock links and incredibly tough.

2016-03-26 15.31.55

The Metal Tech 4×4 replacement adjustable rear lower links feature Currie Johnny Joints plus a unique offset bushing design to give the link a smooth transition surface when in contact with an obstacle helping to protect your axle mount. These links are also a significantly stronger than stock lower links which are prone to bending if hit by a rock. These lower links are made out of 1.75 x .290 wall DOM tubing, use Currie Johnny Joints allowing for increased articulation, up to 30* of rotation. Additionally the links come with poly urethane bushings, 1″ DOM sleeve with .25″ wall support and a grease zirk for maintenance.

Metal Tech 4×4 adjustable rear upper links are built the same as the lower links (Currie Johnny Joints, poly urethane bushings, grease zirk, DOM tubing etc). A bonus to the adjustable links is the ability to correct the pinion angle for proper drive shaft angle on your lifted Land Cruiser.

Tools Needed

  • 19mm Socket (Control Link bolt)
  • 22mm Socket (Wheel Nuts)
  • 24mm Socket (Control Link nut)
  • 24mm Open Wrench (Control Link nut)
  • 5/8″ open/box Wrench (to attach loose Zirk fittings to control links)
  • Rubber Mallet
  • Torque Wrench
  • 12″ Small Pry Tool (The one that comes in the LC Jack kit is perfect)
  • Rachet Strap (Optional – used to keep axle from moving or pulling the axle back into place)
  • PB Blaster (You know what this is for)
  • Jack Stands (hold the truck up and stabilize the rear axle)
  • Floor Jack
  • PTFE Grease (For link bushings and sleeves)

Preparing the Metal Tech Control Links2016-03-26 16.06.21

  • Install Loose Zirk Fittings to MT Links
  • Hand grease each bushing and center sleeve, pushing one bushing into each side of the open bushing shells. Push one steel center sleeve into each bushing shell. (NOTE: Hand grease these parts. The grease zirk is intended for maintenance lubrication, not installation.)
  • Wipe excess grease off powder coated parts, leave grease on the sides of the bushings this will ease installation.

Remove Rear Control Links

Raise the rear of the truck, not just one side. I recommend you do one link at a time. Don’t remove both lower links at the same time. I matched the Metal Tech link to the factory link length since my drive shaft angle was within tolerance. You can line up the MT link with a matching factory link at the eyelets.

  1. Remove Rear Wheel [Torque: 131 N·m (1,340 kgf·cm, 97 ft·lbf)]
  2. Support Rear Axle Housing with Jack
  3. Remove Upper Control Link
    • (a)  Disconnect the ABS speed sensor wire harness.
    • (b)  RH side:
    • Remove the bolt and heat insulator [Torque: 18 N·m (185 kgf·cm, 13 ft·lbf)]
    • (c)  Remove the 2 nuts, washers, bolts and upper control link. [Torque: 150 N·m (1,530 kgf·cm, 111 ft·lbf)]
  4. Remove Lower Control Link
    • Remove the 2 nuts, washers, bolts and lower control link. [Torque: 150 N·m (1,530 kgf·cm, 111 ft·lbf)]

HINT:At the time of installation, after stabilizing the suspension, torque the nuts.

Install Rear Control Links

  1. Reverse the instructions above2016-03-26 19.29.39

Results

Significant reduction in driveline thunk. In my 2000 Land Cruiser it has completely gone. These links were the final step (and most significant) but not the only steps to eliminating the “thunk”. Interestingly when you remove the “thunk” you may hear other sounds :-) I’ve been “thunk” free for 9,000 miles.

As mentioned above this is not a cure all but simply one of the fixes going into a complete solution. In this case it’s also a significant component upgrade for strength and performance. These links have been through some of the toughest terrain in Moab and simply laughed at rocks as they bounced and scraped along the terrain which would have easily bent the stock links.

Resources

Suspension & Axle

Suspension & Axle Instruction

MetalTech4x4.Com

MT Install Instructions

 

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