Fluid change interval....?

[zpx606]

This weekend I plan on changing my diff and transfer case fluids as well as the tranny fluid (30K miles). Have already done a drain and fill at 15K miles but this only changes 4 of the 14 quarts in the tranny.

So...if I use Mobil 1 synthetic fluids, in the future how often will I need to change

1. The Differential fluids.

2. Transfer case

3. Transmission

Also, if you happen to know....how long are the Bosch Platinum +4 plugs supposed to last.

[zpx606]

BUMP....30 views and no input yet?

[nhparrot]

Do you Tow a Trailer or do a lot of Off-Road Driving?

[zpx606]

Thanks for asking.

Do some towing of 4-4500lb trailer. Fairly minimal off-roading.

[nhparrot]

Using your vehicle for towing and off-roading qualifies your vehicle as being used under "Special Operating Conditions".

Under these circumstances, Toyota recommends an every 15k ATF replacement (drain & fill), front differential oil replacement, rear differential oil replacement and transfer case oil replacement.

If you are doing off-roading through deep sand, mud or water it is recommended to check:

Differential oil
Engine air filter
Steering linkage and boots
Transfer oil
Transmission fluid or oil

and to lubricate the propeller shafts (4wd)

[zpx606]

Thanks for the manual review. I wont have to worry about water in the diffs etc.

My question is as follows. Does using Synthetic oils reduce the frequency of changes.

Thanks.

[KLS]

It depends on the brand.
Amsoil sez that their ATF is good for three times a long as conventional ATF, and their gear oil is lifetime.

I think Mobil 1 doesn't say, so you'd be expected to change it on schedule. It might be good for longer, but if they don't say, and you don't get a $15 lab test, you gotta change it.

Ken