LX470 Transmission whine (1 Viewer)

AlpineAccess

Overlanding is an expensive word for car camping.
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Have you removed the front driveshaft, engaged CDL, and taken it for a drive? That should be part of this process.

Do you have any noise while at idle? Change in noise from Park to Reverse, Neutral to Drive?
 
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Have you removed the front driveshaft, engaged CDL, and taken it for a drive? That should be part of this process.

Do you have any noise while at idle? Change in noise from Park to Reverse, Neutral to Drive?
No noise at idle. No noise switching or staying in other gears at idle.

wow ok do removing the front driveshaft and locking the diff. What does that rule out, the front diff? I think I am going to check the front diff and xfer fluids this weekend and then considering what you are saying, but I am not great with these drive trains so I am scratching my head a little with the test you proposed. Thanks for the suggestion!
 
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No noise at idle. No noise switching or staying in other gears at idle.

wow ok do removing the front driveshaft and locking the diff. What does that rule out, the front diff? I think I am going to check the front diff and xfer fluids this weekend and then considering what you are saying, but I am not great with these drive trains so I am scratching my head a little with the test you proposed. Thanks for the suggestion!
I belive you are just removing the load from the front diff by doing that. When you remove the front drive shaft the engine won't load the front diff, you then have to push the CDL so you can drive the truck to test. Maybe with no load on the diff the noise stops

If you didn't lock the CDL the center diff would put power to the path of least resistance (the front shaft since it had no load) with the CDL locked power is split between front and rear shafts instead
 

AlpineAccess

Overlanding is an expensive word for car camping.
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No noise at idle. No noise switching or staying in other gears at idle.

wow ok do removing the front driveshaft and locking the diff. What does that rule out, the front diff? I think I am going to check the front diff and xfer fluids this weekend and then considering what you are saying, but I am not great with these drive trains so I am scratching my head a little with the test you proposed. Thanks for the suggestion!

Exactly, would remove load on diff while deceleration is happening. If you have bad gear lash or bearings, removing the load will either remove the noise or alter it significantly.

CDL needs to be on as noted, because you want to lock output to the rear wheels and not have the vehicle trying to send power forward without the driveshaft in. On full time 4x4 systems this is a very common test.

You can drive around like this in 2wd with no issue.
 
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I belive you are just removing the load from the front diff by doing that. When you remove the front drive shaft the engine won't load the front diff, you then have to push the CDL so you can drive the truck to test. Maybe with no load on the diff the noise stops

If you didn't lock the CDL the center diff would put power to the path of least resistance (the front shaft since it had no load) with the CDL locked power is split between front and rear shafts instead
Makes perfect sense now. Thanks for the follow up! You guys are great on this forum. Much appreciated.
 

AlpineAccess

Overlanding is an expensive word for car camping.
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Makes perfect sense now. Thanks for the follow up! You guys are great on this forum. Much appreciated.

Just keep in mind that if removing the front driveshaft reduces or eliminates the noise, it is just isolating the problem to the front end (and/or your transfer case). This helps to narrow the focus by dividing the vehicle in half forward of the transmission. You then keep dividing things in half through troubleshooting until you're left with one or two options for repairs.
 
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No noise at idle. No noise switching or staying in other gears at idle.

wow ok do removing the front driveshaft and locking the diff. What does that rule out, the front diff? I think I am going to check the front diff and xfer fluids this weekend and then considering what you are saying, but I am not great with these drive trains so I am scratching my head a little with the test you proposed. Thanks for the suggestion!
I changed the front diff, rear diff, and transfer case fluids with mobile 1 75w-90 synthetic. The whine is still there. Lots of gum on the front diff drain plug, but it seemed normal.

I will do the tranny drain and fill several times next weekend.
 
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UPDATE! I changed the fluid in my rears and transfer case with Mobile 1 75-90. I also drained and filled the transmission 4x (it was red again at the end) and loaded the tranny in all gears between drains. At the end I got it to 100degrees F (measured with a IR thermometer) and it was not running out so added 1/2 quart and it started dripping out. I let it run for a little so the new fluid heated up and expanded and then checked again at the check plug and let it run out until it was not a continuous stream (it was now at 102F). Shifts great. No new issues. It was the first change in all the fluids and I have 158K miles on her. Long story short, the Preventative maint is done and cost me $230 (I got a pump) and used Toy WS fluid (prolly not needed). The whine in the front rear is still there when I decelerate same as before. It goes away when I go into N. It doesn't matter if I am in OD or D or if the caris warmed up after a long drive. I first recall this whine about 5Kmiles ago and got worse since then - let's hope it doesn't continue to get worse. I can barely hear it with the radio on, and there is no vibration. Time to live with it!

If it doe get worse I will pull the front drive shaft and lock the center diff and see if that helps. If it helps I will rebuild the front diff. Make sense guys?

Thanks to everyone for your help. Espectially 2001LC - he is the man.
 

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