Diff noise AE86 pre facelift

[R.U.F]

Hi all,
Recently installed a pre facelift 86 LSD. Had the backlash set by pros but disassembled and re assembled myself. It's been making a whinning noise regardless of speed and turn. I'm told it's not a bearing noise and I thought it was coming form the brakes. I have since had the disks machined and new pads installed. I also wound the calipers all the way out and put new pads in. Still got a noise.

Any ideas? Help.

[QikStarlie]

will be backlash. did they check the contact pattern when they set it up? if gears are worn, then they have just set backlash to factory spec. will most likely be your problem.

[R.U.F]

Yeah they checked the pattern and we replaced the crown wheel cos it was scared. I assume they set it to factory backlash. Maybe I need to take someone for a drive who can tell the noise.

[QikStarlie]

replaced the pinion as well?

haven't got metal on metal anywhere? (diff case to body) will transfer any whine x 10

[ROBODISCO_20v]

Put some Red Line 80w140 in it. That fixes everything

[R.U.F]

Thanks Guys.

Gonna get the brakes off and make sure it's not rubbing anywhere. Thanks QikStarlie I'll double check none of the trailing arm mounts, sway bar or lateral rod are pressed together against the arm and transferring a much more mild noise.

[allencr]

replaced the crown wheel cos it was scared.

How about the pinion, they're a matched set???????
Also, the backlash can be correct while the contact patch & bearings for the pinion and carrier are set 100 different ways wrong. The backlash only assures that the the contact patch will be OK on overrun/engine braking/in reverse, that's it, really nothing at all to do with how well it runs going forward under power.
The only reason a mechanic will talk about 'backlash' is to 'dumb it down' for the owner/uninformed, or they don't know shit.

[rollaholic]

did you only replace the diff head? was your previous diff open?

as i recall the axles are different lengths between LSD and open, about 5mm. using the longer axles can cause all sorts of issues, i once bought an AE85 that had this problem on one side - not only was the brake rotor offset by 5mm, when i pulled the axle the end of it looked like it had been attacked by a... i dunno, something that chews up metal stuff.

unfortunately i only discovered this after the diff had shit itself.

you can grind them down and clean up the splines with a file, (which is what i did) or go pro and get a machine shop or similar to do it.

[R.U.F]

Holy crap now you have me worried. I bought the diff complete housing etc. And have fitted the pre facelift LSD unit into the head. The noise is not really that loud. It is constant through regardless of speed and turn. I would hope it is not chewing the end of the axle shaft out.

[rollaholic]

so the diff that came with your housing was open?

mine was the same, constant light noise regardless of turning etc.

pull em out and check, should be obvious. or you'll be able to find a guide online about how long they should be.