Hello all,
I'm pretty new here but I've been lurking for years and since I'm finally in a cruiser I thought I'd contribute. I've read all the threads about older weak diffs and catastrophic failure but I may I have a newer one just dying from neglect. I'll track it as I investigate and update here. FYI I'm a complete novice mechanic so this will all be new to me.
My truck is an LX470 with just over 140k. I bought it at 131k in mid May from a Lexus dealer just as I was about to sell my house in Minnesota and take off with my family to Maine and then across again to our new home in southern Oregon. Took it to a Napa garage for fluid changes (diffs, trans, steering, brake, engine oil, etc.) and they told me the fluids all looked pretty ugly. Also the charcoal canister was shot. And the steering rack was leaking. A few grand later I was on my way and she drove great with new 33" ko2s, except that I noticed the water pump leaking coolant. The next seven thousand miles or so were uneventful until about a week after we arrived in OR.
Just before we arrived here I started to notice fluid dripping under the front skid plate. Then, I was driving about 65 on I-5 and a grinding noise came from the front end. I've since determined that it comes when I take my foot off the accelerator but it lessens when I brake, so it comes when not under load. It doesn't seem to be affected by turning or by changes in RPM. When I first heard it the noise was so loud I drove straight to the local Toyota dealership. They told me my front right axle seal was shot and diff fluid was low. Claim there was dye in the fluid. They replaced the seal and the fluid for an arm and a leg. They told me there were metal shavings in the oil (but can't tell me if it was an unusual amount) and that if the problem wasn't solved I should replace 'the whole diff, housing and all' for over $3k.
Grinding was much less now but continued. I had Toyota replace my water pump, timing belt, serpentine, tensioners, pulleys, hoses, etc. and they told me again I need a new 'front axle assembly' or else I'll die on the highway when it seizes up. Jamister1 kindly offered to help me diagnose it but after my truck sat for a week I couldn't get it to come back so I bowed out. It was replaced by a squeal that sounded like a squeaky belt. Now, the grinding has come back and the squeal is growing more persistent. Especially under load or while turning it seems.
I'm afraid it is front diff worn from years of running old fluid, then low fluid after the seal finally blew. But I'm hoping it might just be u-joints. I'll try to pull the front drive shaft tomorrow and inspect and hope that stops it. Maybe I'll get lucky.
