The Fluids

now that runrun runs, I'm looking for recommendations on which transfer case and differential fluids Y'All recommend. Toyota dealer said not to use synthetic engine oil because it exacerbates engine leaks.

I wonder if that is true in your experience. It may be the reason people say that synthetic fluids affect seals.

I'm wondering whether synth diff fluid would cause axle seal problems. What is the value of synthetics in the gear cases?

What do you run in your runners transfer case and differentials, and why.

Thanks for the input. I have to get this machine on the road soon. Family re-union road trip coming up.

Please message me if you want to, and thanks

we need input

regards,
Michael

 

Synthetics have improved resistance to wear, oxidation and high heat versus non synthetics. Synthetic is pretty much better in all regards other than price. If it causes a leak, the you should replace the seals or gaskets.

 

thanks for the comment. what products do you use in your gears?

 

Weights are more important as modern lubricants are all better than oils over 15-20 years ago.

Lucas 75W-90 was my go to for my Tacoma and 4Runner but switched to Mobil 75W-140 for my Land Cruiser.

 

Valvoline Maxlife in Transmission
Royal Purple Syncromax in Transfer case
Amsoil 75W90 Front and Rear Diff
Quaker State Full Synthetic 5W30 in engine (this will stir the pot)

I am sure you will get plenty more product recommendations from other members.

 

I mean, you being as specific as you were alone can stir the pot

Toyota ATF is great in the A340.

I will say, generally for diffs I'd recommend against a synthetic (even though I use it myself) because non-synthetics separate from water much better.

Also, this is the 3rd Gen section. You have a 5th Gen Limited which, correct me if I'm wrong, is full-time 4WD right? That may (or may not) call for a different oil for the transfer case.

These 4Runners use the same oil for the front diff, rear, as well as the transfer case.

 

Thanks for the responses. A general question, my road trip is going by or thru Death Valley, and across the southwest to Texas. Does 75W-140 imply a better choice for the high heat application, versus 75W-90?

Since this Runner is a total stranger to me, and has scars from a checkered past, and the current fluids are unknowns, I want to provide the gears with optimum choice for the conditions. there was a time when differentials got the oil changed with the season.

thanks again. I'm going to start this oil exchange program tomorrow...

 

When working the diffs, remember to undo the fill first, then work towards the drain.

I say this because most times your drain plug will easily come out. Then you drain your fluid and find out the hard way that you're unable to remove your fill plug.

Get a pick set, and scrape any and all dirt and grime that accumulates in your plugs.

They're hex, and very shallow, so one needs to ensure they seat their tool as deep as possible.

Next up, I'd recommend hammering the back of the hex socket a few times to "loosen" up the bolt in the event that its seized.

Last but not least, remove as stated (fill first).

I used a 3/8" drive for the fill.

Then follow with your drain.

I used a 1/2" drive for the drain.

It'll also be a better time now than ever to replace your hex plugs with regular metric head plugs. These are Lexus variants that most people use.

90341-24016
90341-18060

Don't forget the crush gaskets either.

90430-24003
12157-10010

And if you go as far as replacing your cv axle seals.

90311-47027
90311-47013

As for your oil weight question, you'll be fine to stick with 75W-90. I'll be switching to the other stuff only because I now live in a hot climate and wheel my rigs.

 

Kwikvette, that's super helpful info. I appreciate the part numbers, this will get me going quicker.

Thanks!

 

I've only owned one 1st Gen Tacoma and one 3rd Gen 4Runner but they're nearly identical in every way sans the obvious stuff, and rear suspension.

Worked on both myself as well as helping others. I keep part numbers saved in case others need help.

 

My bad, did not notice the 3rd gen discussion. Good luck OP.

 

For my transferase I used synthetic 75w-90 from Lucas. Does it's job, nothing more to say. For my diffs I used Masterpro 75w-90 synthetic, it's a cheap store brand and it's performance hasn't given me any reason to use anything more expensive. Both those fluids were GL5. Buy the large gallon container of gear oil, I did the fluid change in steps and I kept buying the quart size bottles.

The front diff plug is a pain to get off, it uses a hex bolt that can get stripped, so make sure you spray it with PB plaster the night before. The front and rear diffs use different gasket washers.

That non-sense about synthetic causing leaks is BS, if the only thing keeping leaks from happening is the use of non-synthetic oil then your gaskets are going to need to be replaced soon anyway. Only changing oil viscosity will affect the likeliness of leaks, but then your not following recommended maintenance.

 

NO WORRIES ! I'm glad to hear from you anyway. I've only been owned by a Toyota for a couple of months, and am trying to catch up! If this Runner clears all the hurdles he might have a road trip to tell. Otherwise, if I have to bench him, he might get a stinky loud 3-53. LOL

 

thanks. I use PB Blaster on all the fasteners that are older or crusty. do you use a pump with the gear oil? does it fit the gallon container?

Regards,
Michael

 

The front, rear, and transfer case will use most of a gallon if not all of it. I used a hand pump, it was a pain in the ass to use because the straw kept coming off in the bottle. There wasn't anything better.

 

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