true520

Hey all, having some pretty major issues with my 1987 Toyota Pickup 4x4.. I bought the truck and it was missing the front driveshaft, differential, obviously axles, and had broken locking hubs. I've installed a used differential with rebuilt internals, used front driveshaft, brand new axles, and brand new Mile Marker hubs (not the best, but ballin' on a budget here) Anyway, it all works perfect, minus a loud metal-on-metal whine I get out of the front end anytime the hubs are locked, or the T-case is in 4H. I used 75W-90 gear oil, which I was just informed isn't the proper type, but would the fluid type make that large of a difference on wear and tear? Also, the noise is completely random. May happen as soon as I roll forward, may not happen until 10-15mph. I do NOT use 4x4 at any speeds over 20mph, give or take, as was recommended by others who aren't as new to off-roading as I am.

If anyone could shoot me some advice, it would be greatly appreciated, so thanks in advance!

Thanks, Alex

Shady Cadence

Did YOU get the used diff and have it rebuilt, or did the guy you got it from TELL you it was rebuilt?

true520

When I showed up to buy it, the owner of the junkyard had it broken apart to show me the internals. Still had legible writing on the ring gear, and the spider gear internals all looked brand new.

Shady Cadence

And was this noise present immediately, or did it develop in the first few miles?

You've probably got a bearing failing on you, the rear diff in my 4runner makes a similar noise. It's on the to-do list.

true520

It started as hit or miss, accidentally ran down the road one day with the front right hub locked, and it did it at 15mph then stopped, then again at 30mph, then stopped. It wasn't until I got to work that I realized the hub had been locked. It makes no noise at all with the hubs unlocked, only when the front driveshaft turns the diff & axles. The only annoying thing throwing the idea of a bearing off is that the noise would deviate between the left side and right side, but I suppose the noise could easily travel through the drivetrain, correct? Also, if it is a bearing problem, what would be the easiest way to diagnose and narrow it down?

RJR

There's more to rebuilding a differential than just putting in new parts. Getting the bearing preloads right and the gears meshing at the right depth is critical to long life and quiet operation.

I would suggest contacting ZUK (he posts on this forum occasionally) at www.gearinstalls.com and getting some advice from him. He knows more about Toyota diffs than anyone but the engineers in Japan.

true520

Yeah I'm aware of all the detail that goes into a rebuild, so that's also a possibility that it just wasn't rebuilt right.. I'll know if there's any major internal problems when I dump the fluid out tonight, and will post on here if so. I'm hoping it all comes out clear, metal shavings will not make my week any easier lol. I'll definitely contact him, if necessary. Maybe in the near future for a re-gear anyway, regardless of the outcome. Thanks for the link!

true520

Just ran a couple theories. Front end makes a ridiculous amount of noise on the left side, sounds like it's coming from wheel, so wheel bearing, possibly? Also makes noise on right side, but not quite as loud or often. We locked one hub at a time, rolled forward, listened, unlocked hub and went to the other, repeat.. Made noise on left side, not on right side with right hub locked only though. This was all in 2wd. Then, we unlocked hubs, put truck in 4H, and rolled forward again. Noise persisted, slightly, coming from both sides. Finally to try and just look at where it's coming from, we locked hubs and left in 4H, and rolled twice more. God awful noise coming from left side, almost constantly. Same noise, just not as awful, coming from right side way less frequent. I haven't dropped the fluid yet, but it's pretty apparent the noise is coming from the front end of the truck and not the T case.. Will post another update on the situation pretty soon, we're dropping the fluid after dinner.

true520

I was trying to load a small video that shows the noise it is making... but it says invalid file.

I will see if I can figure that out too

LOL

Shady Cadence

Take a long screwdriver or similar solid rod, place one end on the steering knuckle and put your thumb over the other end, then press your thumb into your ear. Noise will travel through the rod, and you'll get a clearer sound. Then touch everywhere you think might be making noise...the other side knuckle, either side of the diff housing, and the pinion bearing. If they growl loud enough to make you pull your thumb out of your ear, they're bad.

abecedarian

Same size tires front & rear?

And I literally mean SAME SIZE, as in front and rear are the same "size" but also worn the same amount, like the PO rotated them properly?

RJR

Just a thought. Did you lube the ends of the CV axles where they go into the wheels? They run in bronze bushings inside the wheel spindle, and will make noise if they're running dry. They don't turn if the xfer case is in 2wd and the hubs are unlocked, so you wouldn't hear it then.

true520

That would make sense.. I did not, actually. The hubs I installed said "do NOT pack with grease etc etc.." The noise seems to come from the wheels, it's worse on the left than the right. I jacked the left side of the vehicle up, locked the hub, and spun it by hand and it's bad enough to where you can hear it. So pull the axles out, throw some grease in there, and hope for the best?

true520

The front two are worn a little below 50%, rear are brand new. But the fronts are worn very evenly, and both have about the same amount of wear.

RJR

The locking parts themselves should not be packed with grease, just lubed good. However, the part where the axle slides through the hollow spindle needs lubrication. Otherwise it just runs dry in the bronze bushing and will make noise.

There are ways to lubricate the spindle bushing without removing the CV axle, but it might be best to pull them and grease them up good.

true520

Alright, I'm gonna have a mechanic look it over today here at the dealership I work at, just to verify what might be wrong, but I'll definitely be doing that when I get off work, if he doesn't do it for me. Much appreciated, I'll definitely be back on here later to post the results!

skypilot

iTrader: (1)

Nope; Swap one new tire to the front on the same side as the new tire on the rear. What you really need is to have the new tires whacked down to the same diameter as your worn tires, but that's dumb. The real answer is to get two new tires for the front and save the worn tires for spares.

RJR

Matching front-rear tire size is important if you run a lot in 4wd on pavement that is alternately slick and dry. On dirt or other low traction surfaces it's not nearly as critical.

But I don't think mismatched tire sizes are the fundamental source of his noise, since the noise happens even when the hubs are locked in and he's just in 2wd, in which case tire size is irrelevant.

true520

So something strange and confusing happened, but it's all for the better I believe. I had a bolt and washer into the end of the axle, per instructions with hubs. I removed the bolt and washer to pack grease in around where the axle splines to the hub. I put a good bit in, worked the axle around to get some of the grease moved around, then pushed the hub locking mechanism with my fingers, spun the wheel, and no noise. So naturally, I thought "sweet all it needed was grease!" I put the bolt and washer back in, put the cap back on the hub, locked it to spin again, and the noise was there.. So I pulled it back apart, removed the bolt and washer, put the cap back together, and no noise at all now? Really have no idea what that has to do with anything, but not so sure I'm gonna complain.. Lol. I pulled out onto the road, ran the truck up to about 30mph, then the noise came back on the left side. Has something to do with the hub, I feel like I've narrowed that much down. But not sure if I'll worry about it for awhile, highly doubt I'll be going anywhere trail riding at speeds that high.