I changed the transfer case fluid in my '07 GX470 in December using Royal Purple Synchromax, as it was the only aftermarket fluid I could find that claimed to be compatible with the Toyota OEM spec (that costs $50+ per quart). Since then, i sometimes get a relatively quiet gear whine from the transfer case that goes away if I apply light pressure to the transfer case lever. The transfer case was filled until fluid came out the fill plug, so it is full.
I'm thinking this has to be due to the Synchromax. Has anyone else had this problem with this fluid? I'm about to drain it out and pour in some 75W90 gear oil and see if the noise goes away. Any other fluid recommendations that are NOT the $50/quart OEM fluid? I put Lucas 75W90 full synthetic gear oil in the differentials and it seems to work great.
I'm thinking this has to be due to the Synchromax. Has anyone else had this problem with this fluid? I'm about to drain it out and pour in some 75W90 gear oil and see if the noise goes away. Any other fluid recommendations that are NOT the $50/quart OEM fluid? I put Lucas 75W90 full synthetic gear oil in the differentials and it seems to work great.
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