Driveline Clunk. I don't like it. (1 Viewer)

[-Spike-]

Thank you, Dave! Great suggestion.

Looks like not the motor mount after all. Seems like it'll be more work to resolve the clunk.

Also kind of wonder about swapping in a viscious coupled transfer case from the FZJ80 into the FJ80, although not something I want to undertake now.

That will most likely reduce the clunk, as the clunk is amplified when the VC is removed from those t-cases. However, AFAIK the VC is not available new, nor is it repairable, so what will you do when it eventually fails? The easy answer is to remove it...

 

[Zjohnsonua]

80s are failing mounts almost as often as 60s now. Similar design, and the rubber is aging out. A common early symptom is a shudder / vibration when the AC is turned on.

Be mindful of the heater valve when jacking on the engine - the valve cover will likely hit it as you lift the engine to clear the DS mount.

 

[Dave 2000]

Thank you, Dave! Great suggestion.

Looks like not the motor mount after all. Seems like it'll be more work to resolve the clunk.

Also kind of wonder about swapping in a viscious coupled transfer case from the FZJ80 into the FJ80, although not something I want to undertake now.

Sorry for late reply, lots going on healthwise at the moment.

Swapping the transfer box to a VC version really does not makes sense, both from a monetary point of view and usefulness gained which is minimal at best.

One of the downsides of having a VC is they can seize, this results in to all intents and purposes driving with the centre differential engaged, the results are not good.

I do agree that the VC may help with drivetrain 'shunt' which shows up as the mileage piles on. A good thing to do is to replace the front drive flanges and all four UJ's, that alone will be a cost effective option to reduce 'slack' in the transmission.

As an aside, depending on your model year it may have thin or thick front drive flanges? If they are the thin versions and if finance permits it, then replace the CV joints and this will allow the thicker version flanges to be fitted, they are stronger and less susceptible to wear.

Regards

Dave

 

[cruiserdan]

I have encountered exactly ONE seized coupler in 30 years.

 

[-Spike-]

I have encountered exactly ONE seized coupler in 30 years.

I have experienced two seized couplers in trucks I have owned in 18 years.

 

[Dave 2000]

I have encountered exactly ONE seized coupler in 30 years.

Only four for me, none of which were on my own 80 but on customers vehicles, the price when you could get them led to customers having them simply removed, apart from releasing the drive train, it took about 20+ Ib out of the vehicles weight!

Regards

Dave

 

[cruiserdan]

removing the coupler makes the drivetrain noticeably more "clunky "... in my opinion. Your experience may differ.

 

[-Spike-]

removing the coupler makes the drivetrain noticeably more "clunky "... in my opinion. Your experience may differ.

Agreed on that.

 

[leonard_nemoy]

I know a super easy way to fix the driveline clunk....

Let the truck roll 1/2 inch in neutral when going from reverse to drive.

Seudo problem solved.