Couple of Issues I need Advice On... (1 Viewer)

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Nov 29, 2017
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Location
Burke, VA
Guys, please chime in...

1 - Clunk sound after suddenly letting off gas and (typically) transmission has not shifted. I'm able to avoid the clunk if I let off the gas very slowly. My truck also vibrates when it gets to 60-65 and it also makes a clunk from P to R or D. I'm thinking motor mounts and/or U Joints.

2 - Car won't start (No CEL) sometimes in the morning unless I press down the EFI relay. The EFI relay does get hot after running the car, but the no starting thing is 99% of the time when it is cold. I'm thinking relay box contacts?

Any advice is greatly appreciated.

Thanks!
 
Guys, please chime in...

1 - Clunk sound after suddenly letting off gas and (typically) transmission has not shifted. I'm able to avoid the clunk if I let off the gas very slowly. My truck also vibrates when it gets to 60-65 and it also makes a clunk from P to R or D. I'm thinking motor mounts and/or U Joints.

2 - Car won't start (No CEL) sometimes in the morning unless I press down the EFI relay. The EFI relay does get hot after running the car, but the no starting thing is 99% of the time when it is cold. I'm thinking relay box contacts?

Any advice is greatly appreciated.

Thanks!


1. Likely Universal Joint for the clunk and tire balance for 60-65 mph vibration; check motor mounts

2. Would take a lot more diagnosing, but sounds like you have isolate the problem so could be a contact.
 
1. Likely Universal Joint for the clunk and tire balance for 60-65 mph vibration; check motor mounts

2. Would take a lot more diagnosing, but sounds like you have isolate the problem so could be a contact.
Appreciate it!
 
1. Likely Universal Joint for the clunk and tire balance for 60-65 mph vibration; check motor mounts

2. Would take a lot more diagnosing, but sounds like you have isolate the problem so could be a contact.

Your u joints could be ready to go... And could also be the cause of the vibration.
 
If the ujoints are toast they can get stiff and not rotate correctly causing the drive shaft to wobble and bind. Which could cause both issues.
 
One way to check is to remove the rear DS and drive it in 4wd. If it goes away, it's somewhere in the rear driveline and likely the drive shaft. If you do this, inspect and wiggle, pull, push and turn the rear pinion flange to be sure it is in good shape.
 
Try to check/change the transmission mount. Ask me how I know? :rofl:

The mount in my 80 was so rusted, that when I added an Iron Pig skid plate it wasn't worth putting it back on. I didn't have enough time to source a new one before going to coal mine. Luckily for me, the good land cruiser brethren talked me out of wheelin it (I had tie-wire, bungee cords, duct tape, and ratchet straps holding it). I installed a new mount as soon as I got back from the event and the random clunks were gone. Before you start tearing everything apart, have you tried lubing the u-joints/driveshafts? If the transmission mount is rusted good, it's probably moving.

Good Luck!
 
Try to check/change the transmission mount. Ask me how I know? :rofl:

The mount in my 80 was so rusted, that when I added an Iron Pig skid plate it wasn't worth putting it back on. I didn't have enough time to source a new one before going to coal mine. Luckily for me, the good land cruiser brethren talked me out of wheelin it (I had tie-wire, bungee cords, duct tape, and ratchet straps holding it). I installed a new mount as soon as I got back from the event and the random clunks were gone. Before you start tearing everything apart, have you tried lubing the u-joints/driveshafts? If the transmission mount is rusted good, it's probably moving.

Good Luck!

I'll check that. Given the good amount of oil leaks, my undercarriage has minimum rust. That said, I have not lubed the suspension in the 5 months I've owned it. Thanks for the reminder.
 
The clunk is a classic 3fe 80 issue. It's usually the slop in the rear, front and center diff from wear over time. I think this was improved in the later models when the VC was added to the transfer case. Another thing you can check is the front drive plates for wear. Plus, I have read that Green Grease on the drive shaft splines helps but I never tried it.

I found that re-tightening the front wheel bearings once a year helps with vibrations.

There's lots of info on the EFI relay. Most upgrade the harness to larger wires and the contacts do wear out. The relay didn't used to be very expensive so you might want to carry a spare. jonheld has some good info linked to his signature.
 
The clunk is a classic 3fe 80 issue. It's usually the slop in the rear, front and center diff from wear over time. I think this was improved in the later models when the VC was added to the transfer case. Another thing you can check is the front drive plates for wear. Plus, I have read that Green Grease on the drive shaft splines helps but I never tried it.

I found that re-tightening the front wheel bearings once a year helps with vibrations.

There's lots of info on the EFI relay. Most upgrade the harness to larger wires and the contacts do wear out. The relay didn't used to be very expensive so you might want to carry a spare. jonheld has some good info linked to his signature.
Interesting that you mention the VC in later models, that is exactly what the seller told me when I felt the clunk. Thanks
 
Isn't there a problem with the output shaft on the transmission where it goes into the tranfercase or is that a FJ62 Issue? Ryan?

I know the 80 has a different transferase than the 62. There used to be a company in Australia that made a spacer to fix this.
 

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