Differential oil

I finally found out the gear oil in the front is 75-90 and the rear is 80-90 now the question is should I get synthetic or not my car has over 200,000 miles on it and it has never been changed.
that's how it is having a sister that owns the same vehicle before you

 

Either one is fine.
Does you truck have a LSD or is it an open differential?

 

75w90 is the same as 80w90 with a better cold rating. Just run 75w90 gl5

No need for synthetic, just clean conventional oil unless you tow/haul frequently. Even then you just increase intervals.

 

LSD was never a thing in 1st Gen Tacoma's.

 

This.

 

I prefer to not change the fluid so often so I use synthetic. I also driver more miles in four months than the national annual average mileage by a few hundred miles so I really need the longer mileage interval changes. Even with synthetic motor oil and going 25k I'm doing 1-2 complete oil changes a year. While more expensive up front I actually save in the long run with everything. Besides, toyota already uses full synthetic transmission fluid and coolant from the factory.

it not only lasts longer but it actually protects better after adjusting for greater mileage changes; it's far more advanced and has much more wear prevention additives added; it really is better all around. But I always point out after saying that, that I am more anal with fluid changes than most folks...almost all engine/transmission failures are directly related to inadequate fluid, either level or quality, over a long period...lack of maintenance. I see it as, every now and then I'm going to go way over, I have in the past, doing this that will have almost no impact, but if the fluid was lower quality the impact could be more....so I tend to go a bit extra. But I have to acknowledge my thinking isn't "normal" XD.

So in all honesty for most it will come down to how often do you want to change the fluid...the better protection is just bonus.

fyi, I've seen a few threads here with members doing their first diff change at the recommended interval and finding the fluid REALLY dark and that was folks who didn't off road. Better safe than sorry I say. Of course, fluid color is not an indicator of how well it's protecting at that time
you can have nasty dark that still has plenty of anti-wear additives in it *shrug

 

@Flamingskull

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.

$3 90430-24003 Front Differential Drain Plug Gasket

90430-24003

$14 12157-10010 Toyota Oil Drain Plug Crushable Steel Gaskets Set of 10 OEM 12157-10010

12157-10010

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

$11 90311-47027 Toyota Genuine Parts - Seal, Type T Oil (90311-47027)

90311-47027

$25 90311-47013 Toyota Genuine Oil Seal for Differential Side Gear Shaft

90311-47013

As for your oil weight question, you'll be fine to stick with

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 for both. I'll be switching to 75W-140 only because I now live in a hot climate and wheel my rig.

 

I know it's off road four wheel drive high and low where you're not allowed to drive on the drive payment cuz it'll mess it up. I just don't know anything about differentials I keep looking at different types and how they work and I can't figure out or understand what mine is

 

If you have a button to the left of your steering column that says "RR DIFF LOCK" then you have a TRD Package with an electronic rear locking differential.

If there's nothing there, you have an open diff.

Don't let these people from a different generation Tacoma confuse you. They happen to be in the wrong section as their vehicle won't exactly have the same options as yours.

 

I didn’t know that. But then again, I’ve only owned one 1st Gen.

 

Pictures are always a big help.

I have been using 85w-140 in everything since that is what I have.

Thing to remember is with older Toyota Trucks is you just never know what might be swapped in .

 

It's a stick that says 4l 4h N and 2h. Right next to my original stick

 

Yeah, I do have a 2nd Gen.

The real reason I asked, was because some of the 2nd Gen guys have had issues running Synthetic oil in the LSD differential. I was more less trying to look out for the guy. Seriously, sometimes I ask questions in order to get more information to give “better” advice. Which is why i asked the first question.

But I see now, I’d been better off not mentioning it.
Looks like you got him taken care of now. And that’s all that matters.

 

No.

Left of steering column.

Read the post.

 

There aren't too many options available for a 1st Gen, but I can still see how it can be confusing with the added nomenclature.

Especially when newcomers ask if their truck is a Tacoma or an SR5

 

I guess I can’t resist straying from my “section” of the forum.

It looks like this buddy.

 

Understandable; first gen best gen

 

Yeah, I have to say. I MISS my 1st Gen.
It’s where it all started for me. It was by far the most expensive truck I ever owned.
I was bitten by the “mod” bug.

 

You're telling me, it was a gateway drug for me.

Modified Tacoma, to a modified 4Runner, to an 80 series Land Cruiser.

 

I agree. No air injection, and a manual transfer case.
My 96’ even had manual hubs.