Transmission/t-case whine gets louder AND LOUDER…. then what? (1 Viewer)

Polo

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I’ve put over 130k miles on my 79 FJ40 over the last 15 yrs. It’s always had a bit of transmission (or transfer case?) whine and an annoying t-case shifter buzz/rattle.

I get a power-on whine in all gears, but most notably in 4th gear at moderate rpm up an incline. Foot off the gas… no whine.

Over the last six months or so the whine has gotten REALLY LOUD. My question is what happens next? Is catastrophic failure on the horizon?

When do I start looking for a tran$mi$$ion $hop that will do a rebuild?

Thanks in advance for any info or advice!

polo
 

A10Driver

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What fluids are you running and when last have they been checked. Sounds like bearings are going out, try some synthetic oil and see if it makes a difference. Probably do a rebuild before they fail completely, otherwise you are probably going to need more parts/ money to rebuild
 
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As the others have said, check the fluid levels...however, not sure if I would go with a synthetic lube. These things were designed for 80/90 gear oil. These older transmissions and transfer cases had some pretty gross tolerances. The heavier weight oils kinda make up for it....

On the T-case...it’s generally the idler gear roller bearings and shafts. On the transmission, cluster gear bearings.
 
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I’m going through this now. Just had tranny rebuilt and whine still loud as ever. Changed out idler and input gears in tcase and it’s still not fixed. Put it on blocks, put into gear and got under it...definitely coming from tcase, just not sure what. Looks like it needs a full rebuild.
 

Polo

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Thanks for the responses.

I’ve got semi-synthetic gear oil that’s only a coupla years old and a t-case-to-transmission connector hose. I checked all fluid levels last weekend, including the rear diff. All fluids are topped up and fluids appear clear.

I might try to find a shop that will do the t-case first (less expensive) and only do the transmission if the whine remains. In my area (Honolulu) it can be tough to find a shop that wants to take on older vehicles. I'd love to do it myself, but it may be beyond my .5 banana skill.

Polo
 

cruisermatt

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As the others have said, check the fluid levels...however, not sure if I would go with a synthetic lube. These things were designed for 80/90 gear oil. These older transmissions and transfer cases had some pretty gross tolerances. The heavier weight oils kinda make up for it....

On the T-case...it’s generally the idler gear roller bearings and shafts. On the transmission, cluster gear bearings.

synthetic doesn't mean thinner
 

65swb45

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Also keep in mind, with a hollow driveshaft tube acting like a tubular bell, sound is often carried forward from the rear end.

As Mark J pointed out, idler in the TC is a weak point. And unfortunately, the disintegrating bearings often rub through the hard face of the inside of the idler, a point sometimes overlooked by rebuilders. In that case, the gear will continue to whine and deteriorate, taking the other gears with it.

Probably safe to assume that there’s no crosshatching left on the gear teeth. But if the teeth are really shiny, the gear is probably done.

The good news is brand new aftermarket idler gears are readily available from several MUD vendors, myself included.
 

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