3rd Gen Differential and Manual Transmission (6MT) Fluid Change

Sub'd. Nice write up OP!

 

Nice job with this will be great when I get around to this in warmer weather.

 

Sub'd. I need to do this soon as well, and I'll definitely reference this write up.

 

Truck has just over 10,600 miles as of this morning. No fluid service had been done (except engine oil) until yesterday. Looking back I wish I had done it at 5k.

I probably could have re-used most of the washers here no problem. Especially the flat washers for the transmission. The copper washer looked fine but I could see where the drain plug for the front diff seated in. I would definitely replace all of the crush washers simply because the act of tightening a bolt on them plastically deforms them. However, I reused them on my 4Runner when I still had it and all was fine. I guess I just wanted to be sure it was done right and the gasket set is cheap.

Sorry to hear that. I will say if I was on my 3rd Toyota diff I wouldn't be touching anything still in warranty on my own. I wouldn't want to give them an excuse to try and tell me that the fluids I chose don't meet their minimum requirements. I also can't afford a good enough lawyer to prove them wrong if it came to it...

OA

 

This should be a Sticky

 

Remember that Amsoil warranties their products. If the court said the product was at fault, then Amsoil would have your back (I believe that includes the lawyer fee).
Also just want to say that I can't emphasize enough about how smart you are to get the independent lab results of your fluids.

 

Actually it would fail because the OP used a different viscosity oil that is not the required spec, does not matter what Amsoil warranty is.

 

Well, yes and no. You are right in that he used a different weight, no argument there. But his is still a qualifying GL5 product and that is the true -requirement- (the weight is a recommendation). However, the bottom line is: Toyota must prove that the lube caused the failure. If that is accomplished - then Amsoil would go to bat, since that is what their warranty is all about.

 

I performed the exact same maintenance on my truck (2016 TRD Sport manual) at ~15k miles and lubed as well. My rear diff fluid was pretty clean and I don't have the whine either. My front diff fluid was black same as the OPs rear diff oil. Both had black gunk on the drain plug. My transmission fluid looked the best of all 3... my front diff fluid was BLACK ... rear diff dark amber.. trans fluid amber.

Weird that the tranny drain plug was not magnetized...

For anyone interested, we can replace the rear plug with a low profile one from Toyota. The new 8.75 rear had a sort of guard around the plug so that when wheeling we don't rub against a rock a loosen the drain plug. Lots of gen2 and gen1 owners replaced the rear plug with the low profile one. Just an FYI... I have the new low profile plug but didn't get it until after I changed the fluid.

 

Sub for the next nice Midwest summer if it ever gets here. And for lab results.

 

Not only is the weight different but IIRC there is a specific spec that Toyota requires and Redline was the only non Toyota oil to meet it. Amsoil is not going to spend money and go to bat for you if you put the wrong stuff in.

 

I definitely have the diff howl at 55-60mph, maybe that has something to do with it? The diff howl was there today to and from work, but sounded more subdued, I'll give it week or so before making a final determination if it made an improvement or not.

The transmission fluid change was probably the best enhancement yet. The truck positively engages gears, and N to 1, and 1 to 2 aren't even close to as bad as they were for me before hand. Honestly I was shopping heavier aftermarket shift knobs, but this has provided me a similar effect (makes me wonder wtf happened at the factory).

This thread was intended to be instructional, it's up to each owner to do their research and use an oil they think is appropriate. I don't want to get into a discussion about oil types here. I'm sure you're both aware of the BITOG forums and the rabbit hole that can lead to (I've spent more time than I care to talk about researching the specific fluids for this task). That said, @shakerhood I'd like to see documentation regarding Redline being the only producer of a truly equivalent fluid (not that I don't believe you but from my research that may be old information). Both Redline and Amsoil offer products that they themselves recommend for our diffs and transmissions. Some time ago, only Redline made an aftermarket 75w-85, but things have changed since then. As far as I know, the only thing that has no equivalent is our Transfer Case fluid (which is absurdly expensive from Toyota).

When I was doing this service for my 5th gen 4Runner (again, awhile ago now), I wanted to use OEM fluid. Both dealers I checked with said they ordered

$26 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 in bulk for much cheaper and that's all they used (keep in mind the 5th gen also called for 75w-85). Further data, albeit anecdotal, suggests that others have had the same experience. Obviously a dealer can say they did what was spec'd by Toyota and everyone would believe it. I feel comfortable knowing that quite a few trucks out there that have had this service done by a dealer are running the same weight oil as me. I also feel comfortable knowing I've bought the best oil (up for debate of course) for my truck. Many aftermarket oil companies offer these sorts of warranties for their products but I'd be a fool to bank on any of them for back up. If the s*** truly hit the fan I'd cross that bridge when I got to it.

OA

 

Sub'd

 

Was hoping to hear that the change helped get rid of the howl.

 

Haha, I was too! Subdued isn't a bad thing though. Nothing is certain until this gets a bit of use in my opinion. I'll be going to/from Charlottesville a few times this week so that should give me a better idea of what I hear or don't.

OA

 

This is probably a Land Rover/British thing, but I always put hylomar on the threads of the plugs. Extra insurance if the plug starts to loosen or the washer does not seal.

 

Thanks Mr. OP.

I have some questions for the 3rd gen crowd though:

Question 1: fill level of rear diff. I remember years ago, rock crawlers I knew would jack up the rear end to get more differential fluid in the pumpkin. They said since there is no pump in a diff, overfill was OK. It let them get about another quart or so in. Also, they figured when going up/down steep inclines they felt having more fluid helped when the diff was tipped forward and fluid pooled to the front. I didn't think it would be that big of a deal since you are "crawling" but who knows. I see some Dana 60's come with the fill hole at the top to allow more fluid in to the housing these days. Any thoughts on that? It's a thick fluid so foaming shouldn't be an issue with overfill.

Question 2: Is there any brass in a tacoma transfer case? it shouldn't have synchro's in it right? so likelihood of brass is nil I would think? Can't find any GL-4 so want to just use GL-5 but if there's any brass or other yellow metals, guess I'll have to just a GL-4 like redline for the t-case.

Thanks

 

On question 1. Wouldn't overfilling cause the diff to over pressurize at highway speeds? That's what was explained to me.

Air compresses better than oil I'd think.

 

Yep, a rabbit hole to rival the VC tunnels under Chu-Li. So we won't go there. Lots still to be said, but in another forum. I'm good.
I agree with you OP that you've bought the best. Haven't seen anything beat it in 38 years!
Was hoping for the howl to disappear too. Dinna forget to post the lab results. Great job on your thread!

 

I use 6-point sockets to remove the plugs.

I'd like to see Toyota someday change the front diff plugs from Allen to the same as on the rest of the driveline. Those Allens suck, been a pain in every Toyota 4WD I've owned. All the other plugs are usually easy, then you get to the front diff and the cursing begins. Those Allens strip easily, and frankly the recommended torque specs are way too much.

I don't torque the front diff plugs to recommended specs, too damn hard to get out, breaker bar and all.

I've thought about replacing the Allens on the front diff with bolts from the MT or rear diff, no telling if the thread pitch is the same.

EDIT: Front diff fill plug can be replaced with the 24mm hex plug from the transfer case. I didn't try it but I bet the rear diff magnetic plug can go in there, probably all of the 24mm hex plugs can be interchanged.

The front drain plug is much larger for some goofy Toyota reason, it's different from all the others. One can leave it in (I couldn't get it out) and use a transfer pump to get the oil out via the fill plug.