Differences Between Gear Oil? (1 Viewer)

[calskibum]

Hi All,

I'm planning on changing my front and rear diff oil and t-case oil soon. They were changed at a local shop last time and the shop used Redline 75w90 all the way around. This time I'm going to do it myself. Looking on the forum, it appears that most people use Mobil 1, Amsoil, Valvoline, and Royal Purple synthetic gear oil, but not many people use Redline. Are Mobil 1, Amsoil, Valvoline, and Royal Purple synthetic gear oil better suited for the 100 than Redline? I don't have any brand loyalty issues so please let me know if there a reason why Redline is not preferred. I don't want to start a one brand vs. another discussion war, but I appreciate people's input so I can decide what oil to order.

On a side note, I know where the drain and fill plugs are on the rear diff (thanks to the great instructional posts on this forum). Are the plugs on the front diff the same as the rear diff? If not, does anyone have a pic of the front diff showing the location of the drain and fill plugs?

Thanks!

 

[gatormark91]

Front diff plugs are 10mm hex. Take off the fill plug first. Any of the gear oil brands you mentioned are fine. I use 75w90 Mobil 1. Almost all of them have limited slip modifier in them nowadays, so that isn't really anything to worry about.

 

[Clutchee]

Just drain and refil.

Gear oil is like women, everyone’s got their preferences. Just make sure it’s full and rock on.

Personally I use Lucas gear oil.

 

[JayM]

How long have you had the redline in? Synthetic gear oil has a long service interval. If you are changing because you submerge regularly and have water contamination issues you might consider conventional oil.

I use Mobil 1 easy to find and good price. IMO the other boutique synthetics are not worth the extra cash.

 

[Spike555]

If you're using full synthetic gear oil you can easily go 50k.
I used Castrol Syntec, use whatever you want, I always buy whatever brand I like that I can buy locally off the shelf and not have to order and does not cost $20/qt.

With that being said, before you do this, order a compete set of these for your truck, they will make your life so much easier.

Diff Transfer Gearbox Drain Filler Plug Kit suitable for Landcruiser Hilux

 

[Skidoo]

RedLine can be hard find. Also Redline has a crude oil smell, that can be quite strong when hot. I have all diff and t-case vents extended to top of firewall in engine compartment, so smell gets into cabin via cowl vent.

 

[calskibum]

Thank you all for your reply. Sounds like the cost and availability might be the main differences between these different brand of synthetics. I have a little shy of 60K on the current Redline so it's definitely time to change it (I know, I'm guilty and should have had it changed sooner ). I don't do river crossing or submerge them so hopefully they're not too contaminated.

 

[Pyrenees]

Any of the gear oil brands you mentioned are fine.

This. I think I used 75w90 in the transfer case and 80w90 in the diffs. Replace the crush washers. I still need to install the Wits End 10mm hex key diff bolt in the rear. Those 24mm bolts, what on earth were they thinking?

 

[Spike555]

This. I think I used 75w90 in the transfer case and 80w90 in the diffs. Replace the crush washers. I still need to install the Wits End 10mm hex key diff bolt in the rear. Those 24mm bolts, what on earth were they thinking?

Diff Transfer Gearbox Drain Filler Plug Kit suitable for Landcruiser Hilux

Standard 3/8" socket for everything. Done.

 

[hankinid]

This. I think I used 75w90 in the transfer case and 80w90 in the diffs. Replace the crush washers. I still need to install the Wits End 10mm hex key diff bolt in the rear. Those 24mm bolts, what on earth were they thinking?

Copper crush washer on bottom of front diff can be re-annealed and reused with no issues...simply heat it until cherry red, and drop into a can of cold water.

If you're stuck with the front diff hex bolt version, a 15/16" socket provides a better fit than a 25mm.

hth

Steve

 

[2001LC]

Steve are you thinking of the 200 series front differential drain plug copper washer or is this for some aftermarket plug.

The 100 series uses steel crush washer on all differential plugs and aluminium on transfer case.
Rear diff 3.5 US qts
Front diff 1.8 US qts
Transfer case 1.4 US qts

On level ground. Add gear lube slowly until it drips out fill hole. Then let sit for 15 minutes to settle in, then add more fluid until it drips out drain plug.

Differential plugs torque 36ft-lbf
Transfer Case plugs torque 27ft-lbf

Done!

Scored a 2007 Unicorn. The holy grail of 100 series. post #222 has parts numbers.

Front differential plug are on PS side (RH)

 

[calskibum]

Steve are you thinking of the 200 series front differential drain plug copper washer or is this for some aftermarket plug.

The 100 series uses steel crush washer on all differential plugs and aluminium on transfer case.
Rear diff 3.5 US qts
Front diff 1.8 US qts
Transfer case 1.4 US qts

On level ground. Add gear lube slowly until it drips out fill hole. Then let sit for 15 minutes to settle in, then add more fluid until it drips out drain plug.

Differential plugs torque 36ft-lbf
Transfer Case plugs torque 27ft-lbf

Done!

Scored a 2007 Unicorn. The holy grail of 100 series. post #222 has parts numbers.

Front differential plug are on PS side (RH)View attachment 1803879

Thank you very much! The picture is a big help for a newbie like me!

 

[calskibum]

Diff Transfer Gearbox Drain Filler Plug Kit suitable for Landcruiser Hilux

Standard 3/8" socket for everything. Done.

I was wondering why you recommended these, but now I understand.

 

[reznunt]

Just drain and refil.

Gear oil is like women, everyone’s got their preferences. Just make sure it’s full and rock on.

Personally I use Lucas gear oil.

Same here

 

[planomateo]

If you have an advanced auto near you, search the net for a 20-40% coupon and use that to save some cash.

 

[2001LC]

Here some more picture of front differential.

I fill with hose from above.

 

[2001LC]

Here's transfer case. Socket is a 24mm which is used here and on rear differential.

PITA pump works just slow.

 

[2001LC]

I like to use my 3/4" drive breaker bar when ever I can to break nuts & bolt loose, make easy work of them.

After filling and letting lube settle for 15 minutes, I check level. Minimum is 5mm below drain plug, or just top again until runs out. Just make sure to let it stop dripping before torquing in plug with new washer/gasket, so not to overfill.

 

[Pyrenees]

Lol i would have loved to see those pics last month when I was trying to figure that stuff out.

 

[2001LC]

Lol i would have loved to see those pics last month when I was trying to figure that stuff out.

They're old pictures I've posted before. If you read through my links, you'll find all basic PM and much more. But I'll warn you, It is a lot of reading and a lot of pictures to get through.

In the: Engine replacement Scored a 2007 Unicorn. The holy grail of 100 series. you'll find and index in OP, as it is really a long thread.
The link: Thread of links to previous projects and much more. has tons of stuff.