80 Series Handling at Highway Speed (1 Viewer)

[jmkfzj]

All-

I just purchased a 1996 FZJ80. The truck was traded in at a local Ford dealer for a new truck. Clean, 1 owner CARFAX report, whole life in CA with 97K original miles. Although it clearly had some body work on the rear passenger side at some point, a local 80 series/cruiser specialist cleared the frame with flying colors. My question is how do these trucks generally handle at highway speeds? Mine seems very smooth until I get on the freeway and then has some minor vibrations/shaking the starts around 60+ or so MPH. The vibrations seem to come and go and intensify some as speed increases, so maybe it is characteristic of the solid front axle on different sections of freeway? The mechanic did tell me that I need to have the front axle knuckles rebuilt sooner than later. Can anyone describe the way a stock 80 series handles on the freeway? Is it supposed to be Lexus smooth, or is there some roughness to it? Any info would be greatly appreciated. Thanks.

 

[scottryana]

It should handle like a body on frame truck with a solid axle. It is not going to be Lexus sedan smooth, but it shouldn't ride like a 70's pickup either.

I would start with all the normal things.
- How are your tires?
- All inflated to the same pressure?
- Have they been balanced? Road force balanced?
- Are you driveshafts lubricated?
etc

 

[bigredmachine]

could be a u-joint or needing a tire balance causing the vibration issue.

they handle like a solid axle truck on the highway, not going to ride like a new car but should be a fairly smooth ride.

 

[COYS]

All-

I just purchased a 1996 FZJ80. The truck was traded in at a local Ford dealer for a new truck. Clean, 1 owner CARFAX report, whole life in CA with 97K original miles. Although it clearly had some body work on the rear passenger side at some point, a local 80 series/cruiser specialist cleared the frame with flying colors. My question is how do these trucks generally handle at highway speeds? Mine seems very smooth until I get on the freeway and then has some minor vibrations/shaking the starts around 60+ or so MPH. The vibrations seem to come and go and intensify some as speed increases, so maybe it is characteristic of the solid front axle on different sections of freeway? The mechanic did tell me that I need to have the front axle knuckles rebuilt sooner than later. Can anyone describe the way a stock 80 series handles on the freeway? Is it supposed to be Lexus smooth, or is there some roughness to it? Any info would be greatly appreciated. Thanks.

I pulled off an intercontinental 2,300 mile drive in the span of three days last month. The 180K mile LX450 on an OME suspension drove buttery smooth at all speeds up to 75mph (I didn't go any faster). Rode on BFG K02s.

 

[gummycarbs]

Mine seems very smooth until I get on the freeway and then has some minor vibrations/shaking the starts around 60+ or so MPH. The vibrations seem to come and go and intensify some as speed increases,

I'm pretty sure that a stock 80 in proper tune (i.e. no out-of-balance tires, bad u-joints, etc) should be smooth to whatever speed the motor will pull.

It's most likely that you have out-of-balance tires, worn u-joints, or a lift was done without properly correcting the caster. Worn steering components (tie rod ends mostly, but steering box wear, too) will exacerbate it.

so maybe it is characteristic of the solid front axle on different sections of freeway?

Absolutely not.

 

[jonheld]

If the "vibration" is a thump thump thump, then look at tire balance.
If the "vibration" is a buzz, then look at driveline.

These trucks are not modern day sports sedans, so it's important to keep things in perspective.

In the immortal words of Norm Needham:
"Shifter vibrates, mirrors oscillate, bonnet pulsates, dust permeates, engine palpitates, tyres agitate, eyeballs rotate, hearing vacillates, bank account fluctuates, and relationships disintegrate. You get all this and more when you drive an 80 series truck."

 

[REKCUT]

You can also add in control arm and panhard bushings. After i moved tires around with no change, and cleared the U joint question i replaced bushing in front and that smoothed my ride out. My front control arms bushing looked fine but when i loosened up bolts and removed they were shot.

 

[Tools R Us]

Check the knuckle grease level, add moly grease as needed to bring it to 1/2 to 3/4 full. If the grease is low, the bushing and birf are likely running dry, will cause a highway speed rumble and greatly accelerated wear.

 

[greentruck]

Another analysis tip. You can drop the front and rear driveshafts, alternatively, locking the center diff so you can run on just one driveshaft. The info is here to do this. If the issue resolves when one shaft is out, look to it for the problem. If neither does, then look more to the front axle, wheels/tires, etc that turn regardless of whether the driveshaft is in or not.

We had a vibration similar to yours in terms of when it showed up when we first bought our truck. Turned out a yoke on the front DS was tweaked, so just doing the U-joint wouldn't have held up. A good shop can applys and balance a new yoke if that's the issue, but I think you need to do further analysis to pin down what you are dealing with.

 

[jmkfzj]

Wow! The tips thus far are excellent! I greatly appreciate the feedback. So it's pretty clear that a thorough diagnosis is needed, but issues like these are not uncommon on a cruiser. More tips/advice are greatly appreciated!

 

[greentruck]

Wow! The tips thus far are excellent! I greatly appreciate the feedback. So it's pretty clear that a thorough diagnosis is needed, but issues like these are not uncommon on a cruiser. More tips/advice are greatly appreciated!

Gotta remember these trucks are built to take you to heck and back. Sometimes people interpret that to means you can abuse them indefinitely. They will keep going and get you back. Once the problem area is identified, it's usually a straightforward fix and then forget about it, it's solved. Mostly old school mature technology, with a few very worthwhile tech updates (depending on your opinions of ABS, etc, YMMV). Welcome to the fun and madness.

 

[Dave 2000]

I'm pretty sure that a stock 80 in proper tune (i.e. no out-of-balance tires, bad u-joints, etc) should be smooth to whatever speed the motor will pull.

This ^^^^^^^

Mine is stock drivetrain wise bar brake mods, and moly steering gear. It matters not whether I am at 50 MPH or 120 MPH, (the speedo needle hitting the trip reset), she is as smooth as you like. I have stock OE shocks, OE rear springs, and known brand front springs.

If your steering box needs a little adjustment, she will feel a little vague in the straight ahead position.

Regards

Dave

 

[sunrk]

My 80 with all it's tweaks and charms (!) handles really good on highways doing about 100 kph which is just under Australian legal top speed on almost all main highways/freeways of 110 kph. I've never had it going must faster, and when towing a load I never go anything over about 80 to 90 kph.

Number one cause of handling is tyres (balance and pressures significantly different) IMHO. Esp with big(ger) 285/75r16 Cooper AT3's that I'm running.

 

[yellowgeko]

I didn't even read the responses because I am lazy but I a similar (if not exact) issue with mine and ended up throwing a lot of money at it until I found out what it was. First, I replaced and balanced all the tires; then I did a complete front axle rebuild with all Koyo bearings on everything; then I replaced all the u joints (front and rear). What it turned out to be was the front differential pinion bearing. I would have someone check that first, it wasn't cheap to replace and requires the axle to be disassembled. Mine did the exact thing yours was doing. For what it was worth I drove like that for a long, long time, and it didn't do anything bad. It was just super annoying.

 

[jmkfzj]

Thanks yellowgeko, good tip and encouraging to know that annoying doesn't always = serious issue.

 

[lumbee1]

If the steering wheel shakes at 60+ mph, I would bet it's a out of round tire or unbalanced tire. I would find a good local tire shop and ask them to check the balance of the tires. This is fairly easy and cheap to do. Driveline vibes on the other hand are like going down the rabbit hole. Start with the U-joints first. Drop the drive shaft and without adding grease, rotate the joint to see if there is any binding. If that checks out, add grease and reinstall.

 

[Nay]

You can drive a lifted 80 on 37” tires over interstate expansion joints around corners at 75 mph with nary a shake.

Some NVH? Yea. There’s a dial in the stereo for that once you’ve crossed off the usual suspects.

 

[jmkfzj]

UPDATE: I decided to check the wheel balance to rule out. Took the Cruiser to a reputable tire shop in Mission Viejo, CA (Bymar Tire and Brake) where they remounted the tires and performed a road force balance. I'm happy to report that this COMPLETELY resolved my issue! The 22 year old Cruiser now handles/rides smoother than my 2014 Suburban! Thanks to the group for recommending to start with the wheels. Best $100 I've ever spent!

 

[Tools R Us]

Good deal, easy fix! Still check/replenish moly level in the knuckles, bet they are low/empty. Also sample front axle for moly contamination, if needed, change it. If ignored, this is one of the key things that can add big $$$ to '80 maintenance.

 

[LINUS]

^^^^ +1 to Kevin’s advice.

We as a whole are a little overboard with PM work, but now that these 80’s/450’s are ALL a minimum of 20yr old rigs, all fluids need a swap, and starting low & checking your grease, checking diff fluid level, and hitting all the zerks with a grease gun is pretty necessary at this age.

Oil & coolant more commonly get the servicing, but rarely do you hear of or see a receipt from a prev owner for brake fluid or trans fluid swaps, let alone transfer case or diff fluid.
And I bet the majority of 80’s saw their first real front axle service by owners who frequent this board.

Just on pure age it’s not kooky to keep a spare EFI relay or fusible links stashed in a ziplock bag somewhere in the rear quarterpanels.

Your purchase with 97K on it is nice in the sense that hopefully yours makes all the right noises & you know what it’s supposed to act like, so you can keep it in that level of run-ability.