Whining Transmission Normal?

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Sorry, back on this again.

Had a bit of a strip down around the centre console and HEVAC panel at the weekend, and moved the car with no interior fans whirring and a fair bit of the trim out.

With this lot out and nice and quiet inside, I can hear a good and crunchy whirring bearing noise from just below and perhaps slightly in front of the gear selector (4.6 auto) which changes with engine speed. Really need to get my stethoscope out underneath but a bit too cold and wet right now!

From memory, this would be about where the gearbox sits. Gearbox is also getting a little keener than it used to be to hold onto 1st when it's cold.

Still doesn't explain my whine varying with road speed, but it can't be a good thing!

I think I can guess where this is going but does this sound like a bearing on the gearbox input shaft on the way out?

130k miles on the car. Bills for an ATF and filter change at about 65k and another by me less than 10k ago (what came out was quite nice and clean). Early history a bit sketchy but seems to be a reasonably well-loved car with maintenance to match. Gearbox likely to be failing at this mileage?
 
Sorry, back on this again.

Had a bit of a strip down around the centre console and HEVAC panel at the weekend, and moved the car with no interior fans whirring and a fair bit of the trim out.

With this lot out and nice and quiet inside, I can hear a good and crunchy whirring bearing noise from just below and perhaps slightly in front of the gear selector (4.6 auto) which changes with engine speed. Really need to get my stethoscope out underneath but a bit too cold and wet right now!

From memory, this would be about where the gearbox sits. Gearbox is also getting a little keener than it used to be to hold onto 1st when it's cold.

Still doesn't explain my whine varying with road speed, but it can't be a good thing!

I think I can guess where this is going but does this sound like a bearing on the gearbox input shaft on the way out?

130k miles on the car. Bills for an ATF and filter change at about 65k and another by me less than 10k ago (what came out was quite nice and clean). Early history a bit sketchy but seems to be a reasonably well-loved car with maintenance to match. Gearbox likely to be failing at this mileage?
The 4HP24 box seems to fail very rarely.
 
Hi Thanks,

Front diff replaced with a rebuilt Ashcroft unit a few months back. Improved things a little (Pinion bearing had a good deal of play). Also transfer box replaced about a year ago - again with Ashcroft rebuild.

UJs and VC all look good. So only gbox and rear diff to go for the full set :(

Seen the good reputation of the ZF box but wondered just what the typical life is. Had a Merc box go at 160k once (internal bearing chewed its way through its mounting with quite a bang) but otherwise been pretty lucky with autos.

Definitely something grinding away in that area. And now with all the trim back in, I can just hear it as a gentle fizzing increasing with load.

Now with RAVE in front of me, I see the noise is coming from the back end of the gearbox. Internals of autos a bit of a mystery to me. Anything rotating at engine speed towards the back of the gearbox? Presumably it's a bit like manual with lots of internal parts spinning even in neutral.
 
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Hi Thanks,

Front diff replaced with a rebuilt Ashcroft unit a few months back. Improved things a little (Pinion bearing had a good deal of play). Also transfer box replaced about a year ago - again with Ashcroft rebuild.

UJs and VC all look good. So only gbox and rear diff to go for the full set :(

Seen the good reputation of the ZF box but wondered just what the typical life is. Had a Merc box go at 160k once (internal bearing chewed its way through its mounting with quite a bang) but otherwise been pretty lucky with autos.

Definitely something grinding away in that area. And now with all the trim back in, I can just hear it as a gentle fizzing increasing with load.

Now with RAVE in front of me, I see the noise is coming from the back end of the gearbox. Internals of autos a bit of a mystery to me. Anything rotating at engine speed towards the back of the gearbox? Presumably it's a bit like manual with lots of internal parts spinning even in neutral.
Plenty of 4HP24's with over 300K. Any oil in the transfer box?
 
Any oil in the transfer box?

Given it's only just been rebuilt and fitted I should hope so!

However, having found a dry spot to peer underneath, it does look slightly moist with red ATF on its outside. Still clean enough to be the remains of filling it originally, but...

Will check and report back.
 
So it was the rear diff in the end.

No sign of problems until prop and half shafts were disconnected and then it was noticeably notchy when turning the pinion.

Rebuilt diff in there and now nice and quiet. :D

Found a small weep between transfer box and gearbox whilst poking around - was a seal - fixed under warranty.

Better be careful, getting near the end of my list of jobs...
 
How much do your props turn before they "engage" with the rebuilt diffs if you twist one way then the other?

Sorry, only just seen this - subscribe seems not to have worked.

I'll have a look this evening. Not much is the answer, but I'll try to quantify it.
 
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