Builds AK HJ-75 (1 Viewer)

[AirheadNut]

Depending on the condition of your front axle and driveline you could try driving with just the front installed. When I was dealing with bad vibrations in my rear driveshaft I drove a few miles with the rear shaft removed and it was completely smooth.

 

[FJBen]

Have you tried 4th gear at 60/65 vs 5th gear and see if that vibration is still there?

Unfortunately I’m feeling a vibration in mine as well although we drove it decent speed down a really washboard road so it’s possible I threw a wheel weight.

Mine feels almost like a driveline issue so who knows. I’m going to be dropping soon for a clutch anyways

 

[coldtaco]

Depending on the condition of your front axle and driveline you could try driving with just the front installed. When I was dealing with bad vibrations in my rear driveshaft I drove a few miles with the rear shaft removed and it was completely smooth.

Someone suggested that too, just wondering if it will get to 65mph on the front. Might try that tomorrow

 

[coldtaco]

4th gear at 60-65mph seems a bit high

 

[AirheadNut]

Someone suggested that too, just wondering if it will get to 65mph on the front. Might try that tomorrow.

I got mine up to around 60mph in front wheel drive and it was smooth as butter. I’m sure it really depends on the condition of your front axle, hubs and driveline though.

 

[sodafeld1]

So I removed both driveshafts and had my wife start the truck and run through the gears all the way to 5th gear. The rear output flange stayed nice and true as far as I could tell. I didn’t hear or feel anything weird coming from the transfer case, but there was no load on it.

the preload is a very fine measurement, closest I could get was the lowest setting on a bicycle torque wrench without engaging a click. It feels firm but turns fairly freely by hand, doesn't fly when spun, no side movement. The proper dial gauge is an expensive rarely used tool.

I guess there is a preload on the diff too, never went there yet. Point to note too is very often the front diff is very much in better condition than the rear unless spending all it's life in 4wd. Dodgy indie mechanics may just swap diffs over and call it a 'rebuild' on the hj75.

So there is no visible slop on the flange, I had slop in the flange. The transfer has been well designed to adjust the preload which is a point to take note in itself.

When I tightened the preload and put new uni's on the driveshaft, it eliminated the vibrations which were very noticeable over 80km/h. Horrible unnerving vibrations. The original shim had been cut through by the bearing race by the sloppy lack of preload. The factory shim is very thin and the range of preload shim sizes suggests a sensitive , considered adjustment.

I feel the tinniest vibe on my pedal foot when going over 100km/h, but I have no floor insulation, just straight metal, bitumen felt and paint. So I feel and hear absolutely everything, kind of like it that way. This vibe does not concern me especially if I can achieve 11km/l, it mustn't be too out of whack at that fuel consumption for it's age and what it does, imo. One day I will have to do the gearbox and transfer, which I have a spare to rebuild at my leisure.

It is hard to find a subtle vibration from here. When I drive my 84 merc, that is smooth but needs new rubbers, middle exhaust rattles when cold, my wife's 94 mazda has lots of rattles, the 88 troopy makes all sorts of noises! All different beasts.
If you went over all suspension , balancing, steering and drive line, I don't know. I am waiting to drive someone else's troopy to just compare the difference one day.

What is your fuel consumption over a longer drive? That may also tell you a little bit if something is wearing or out of whack imo, as your dyno numbers are excellent. Does it feel good on the highway? I guess 'feel' is a pretty loose term tho.

Sometimes I expect too much perfection from a 34 year old leaf sprung highway tractor. I have seen a few very neglected hj75's and bj40's which still ran fine for many years.

Shall be interesting what you find, some would just live with it.

 

[coldtaco]

The vibration is too disconcerting for me, it’s pretty obvious. I’ll try a couple of things suggested tomorrow.

 

[sodafeld1]

The vibration is too disconcerting for me, it’s pretty obvious. I’ll try a couple of things suggested tomorrow.

roger that, only the owner driver really knows if it is something to be worried about. Slight vibration can be misunderstood, sorry about that. Fight on

 

[jblueridge]

This kind of thing always appears just before a trip.
I had the 74 loaded up for a month's camping. Waved goodbye, turned the key and the freakin dash lights started blinking as if alternator had gone off. I disabled the pre-heater and all is well.

Have you rotated tires? Maybe its a combination of small imbalances. I now have a wop wop wop sound that is either a tire or maybe loose wheel bearings.

 

[coldtaco]

Yup, rotated tires, didn’t help much if any

 

[FJ73Texas]

Take it to discount tire and ask for ride matching. If the problem is with the tire/wheel assy, it will show up during ride matching and they can tell you. I don't know why but they don't always train all the employees this procedure so you may have to wait until they have the trained person to do this for you.

 

[coldtaco]

Thanks sodafeld1 for the info on how to check the rear wheel bearings. They were loose. I followed your advice on tightening the front and rear bearings. All vibrations seem to be gone, but it sometimes still feels like something wants to start shaking See how it goes. Might do them all again just for “fun”

 

[sodafeld1]

Thanks sodafeld1 for the info on how to check the rear wheel bearings. They were loose. I followed your advice on tightening the front and rear bearings. All vibrations seem to be gone, but it sometimes still feels like something wants to start shaking See how it goes. Might do them all again just for “fun”

that was aussiehjcruza about the fronts. But the hammer is the go the more you think about it.

 

[Omrib]

Thanks sodafeld1 for the info on how to check the rear wheel bearings. They were loose. I followed your advice on tightening the front and rear bearings. All vibrations seem to be gone, but it sometimes still feels like something wants to start shaking See how it goes. Might do them all again just for “fun”

Hi
Not sure if I have missed any piece of info or not, hope I am not doubling on someone.

You have stated that the vehicle still "wants" to vibrate sometimes.

If the vehicle (usually front end) is inherently unstable it may be related to improper geometry which, combined with high unsprung weight (front live axle, with large wheels and heavy steering components), can result in "Death wobble" phenomenon or just "want" to go there...

The phenomenon is usually mitigated by removing all slack from the system
Spring bushings kingpins, panhard and sway bar links and bushings (if applicable), steering and other ball joints elevated tire pressure etc.

However all of these just mitigate the problem which is usually rooted in the OEM, or modified geometry of the vehicle.

In many cases, increasing the caster angle (especially, if was reduced due to lift or other mod) will help a lot.

Steering dampers also help but are usually not the source (lack of).

If I had to stack the action items, I would
Check for proper tire pressure fitting the weight and the tire size and type.
Inspect the tires for uneven wear and stepped wear (usually due to succeeding events of hard braking , like in brake tests)
Measure and correct all steering angles (especially caster)
Iradicate all slack in the system.
Cycle the wheel position and/or replace tires.
Recheck (in the end) wheel balance.
Check steering damper and front dampers and bushings.

Having said all that, I am not familiar of the "Death wobble " phenomenon in landcruisers... .
I have encountered it on many leaf sprung and stiff radius arm'ed vehicles like JEEPS and F-Series Super Duties.

Another good reference point is that in most severe cases, if you could keep side load on the steering and suspension, past the trigger speed, like entering a long curve exiting it above reference trigger speed, you would usually escape that specific encounter.
However, you would "reset" when reducing back to below trigger speed...

I also, may have missed the whole point here, as most actions were aimed at driveshafts, t-case flanges, wheels etc. Which may point to a different type of vibration (and cause) which is much more directly connected to specific rolling speed with less relation to road condition or side loads.

It is sometimes hard to interpret from writing without actually getting hands on.

I hope this helps
Keep posting so we can get smarter.
Good luck

 

[coldtaco]

Thanks for the input. Death wobble it is not fortunately. Through all of this I have never felt anything in the steering wheel. I am ordering a rear axle rebuild kit for later. I did the fronts two years ago but will go ahead and redo those. Waiting for replacement shocks for the rear from TT. Everything else Front suspension wise is newish, been replaced in the last 5 yrs.

 

[sodafeld1]

Thanks for the input. Death wobble it is not fortunately. Through all of this I have never felt anything in the steering wheel. I am ordering a rear axle rebuild kit for later. I did the fronts two years ago but will go ahead and redo those. Waiting for replacement shocks for the rear from TT. Everything else Front suspension wise is newish, been replaced in the last 5 yrs.

Looking forward to see the axle rebuild. This vibration would be doing your head in.

 

[Omrib]

Hi
Not sure if I have missed any piece of info or not, hope I am not doubling on someone.

You have stated that the vehicle still "wants" to vibrate sometimes.

If the vehicle (usually front end) is inherently unstable it may be related to improper geometry which, combined with high unsprung weight (front live axle, with large wheels and heavy steering components), can result in "Death wobble" phenomenon or just "want" to go there...

The phenomenon is usually mitigated by removing all slack from the system
Spring bushings kingpins, panhard and sway bar links and bushings (if applicable), steering and other ball joints elevated tire pressure etc.

However all of these just mitigate the problem which is usually rooted in the OEM, or modified geometry of the vehicle.

In many cases, increasing the caster angle (especially, if was reduced due to lift or other mod) will help a lot.

Steering dampers also help but are usually not the source (lack of).

If I had to stack the action items, I would
Check for proper tire pressure fitting the weight and the tire size and type.
Inspect the tires for uneven wear and stepped wear (usually due to succeeding events of hard braking , like in brake tests)
Measure and correct all steering angles (especially caster)
Iradicate all slack in the system.
Cycle the wheel position and/or replace tires.
Recheck (in the end) wheel balance.
Check steering damper and front dampers and bushings.

Having said all that, I am not familiar of the "Death wobble " phenomenon in landcruisers... .
I have encountered it on many leaf sprung and stiff radius arm'ed vehicles like JEEPS and F-Series Super Duties.

Another good reference point is that in most severe cases, if you could keep side load on the steering and suspension, past the trigger speed, like entering a long curve exiting it above reference trigger speed, you would usually escape that specific encounter.
However, you would "reset" when reducing back to below trigger speed...

I also, may have missed the whole point here, as most actions were aimed at driveshafts, t-case flanges, wheels etc. Which may point to a different type of vibration (and cause) which is much more directly connected to specific rolling speed with less relation to road condition or side loads.

It is sometimes hard to interpret from writing without actually getting hands on.

I hope this helps
Keep posting so we can get smarter.
Good luck

I hope it goes away with the axle rebuild.
Nobody likes, squicks....everyone hates vibration.
This is the kind of voodoo you need to master to get rid of it
This is avery thorough process, you are executing, I am sure you will find it and kill the gohst

 

[coldtaco]

Finally all done with working on the Ute to start vacation tomorrow. Last was extended diff breathers.

 

[sodafeld1]

Finally all done with working on the Ute to start vacation tomorrow. Last was extended diff breathers.

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so you got rid of the vibe?

 

[coldtaco]

so you got rid of the vibe?

Mostly. Gonna go anyway, we can always turn around