PTU Fluid - Where Is It Going?

[GrolarBear]

Spring of 2019, my 2012 SHO got yanked out of a parking space by a tow truck improperly, both WRT that it shouldn't have been towed, and it was pulled out dragging the back tires out of the space. After that, I had a noise that was intermittent and we (me, a Toyota Tech friend that both heard it and drove it, and a dealer that I talked to but never managed to hear it) thought was the PTU, but after a few weeks of me trying to get it to the dealer to hear it, it just went away and never came back.

Anyway, I decided to do a PTU fluid change (If it's just sludge then it's good, if there's any chunks I need to dig into this more). I added a drain plug and only a few drops of very thick sludge came out. I know I debated pouring some Kerosine through it to clean it out (in the fill, out the new drain), I don't remember if I dared to, and I did 2 fluid changes and drains to clean it out (only got sludge, no hard parts, nothing metallic at all, nothing that would stick to a magnet) and decided that after the next oil change or 2 I'll swap it again and then do it every 25-30K miles. Filled it with RP Max Gear 75w-140.

I decided that I'm changing the oil, trans fluid, and PTU fluid this weekend. I have no signs of leaks anywhere on the drivetrain with only a little bit of greasy build up on the top of the transmission fill cap and the cap on the vent tube at the top/back middle of the engine. I opened the PTU drain plug and only got dripping out of it, maybe a total of 1/2 a cup if that.

Where the heck is the fluid going??? Is it possible it's going into the trans case somehow?

 

[SHO_Off420]

Is the outside of the casing dirty? The only place for it to go is out the breather hole in the top when it overheats

 

[SM105K]

Here is a very good explanation by a member on here named Mr.HighCaliber.


"PTU's don't fail at least not from a power handling perspective. These only fail from lack of maintenance. Spun bearings and galling of the gears from lack of lubrication.

High Heat dries up the lighter oil molecules in the ****, which causes more heat due to lack of lubrication (thermal runaway) which leads to the remaining gear oil turning to thick black paste which clogs up the vent tube in the ptu which cause pressure buildup in the ptu which forces the remaining, non-congealed fluid out past the shaft seals. Now the only left is a thick paste thats easily flung off of the gears, sticking only to the case. After this chain of events, the bearings run dry and begin to fail, next are the gears. Tolerances widen or things begin to sieze. Bearing and gear noise are usually the first signs of mechanical failure.

But the PTU internals are stout. The weakest part of our powertrain is the RDU Atc coupler. (The electronic coupler in the rear differential). At least in terms of tq capacity and power handling."

 

[mrhighcaliber]

Its paste now coating the inside of your ptu!!!

Since you have a drain installed already, flush some kerosene or brake kleen thru, then follow the directions below.

1) Add 4oz of trans fluid to 12oz of 75w140 gear oil.
- Fill her up.
- Go on a long high way drive 50+miles and change.
- Drain and refill with the same mixture.
- Drive a few hundred miles (a week or so)
- Always drain it hot or warm.

Great job on installing a drain plug, you're ahead of the game.

Beware, the capacity is 16-18oz. Actual capacity will be less than this range based on sludge content.

2) Change your mixture to 2oz ATF with 14oz of 75w140.
- Run this for up to 15,000miles.
- Check and clean the fill plug magnet often, at least every oil change.
- Change if necessary.
- Always drain it hot or warm

This mixture is safe to run for this up to 15,000mi interval. You can run it permanently or just for a few changes as a flush, before changing to 100% 75w140.

- Make sure you vent is clear.

Running just gear oil will take many changes and many miles to dislodge the sludge, with less than thorough results. Also, the mixture will be very thick. That's where the ATF comes in.

The ATF will break down the sludge but also help keep the sludge/paste from thickening the fluid.

I've saved 2 ptus this way and they're both fine to this day.

Sent from my PH-1 using Tapatalk

 

[Sgtmeatsauce1]

Yea what he said....btw I use AMSOIL ONLY.

 

[luigisho]

The ATF will break down the sludge but also help keep the sludge/paste from thickening the fluid.

I've saved 2 ptus this way and they're both fine to this day.

Sent from my PH-1 using Tapatalk

Who's better than this guy! Love that stuff.

 

[krewat]

Yeah, I was going to mention solvents boiling out of the synthetic oil...

 

[GrolarBear]

Its paste now coating the inside of your put!!!

Royal Purple Max Gear 75w-140 after what I'm guessing is about 10,000miles??? I have a hard time believing it.

Since you have a drain installed already, flush some kerosene or brake kleen thru, then follow the directions below.

Remembering better what I did last time, I stuck a tube in the filler and sprayed a bunch of brake clean in there, let that dry a little and then I flushed about 2 quarts of kero through it in 2 batches (one the first day, let it all drip and dry overnight, another quart the second day just to see how clean it was, came out as slightly grey looking Kero)

1) Add 4oz of trans fluid to 12oz of 75w140 gear oil.
- Fill her up.
- Go on a long high way drive 50+miles and change.
- Drain and refill with the same mixture.
- Drive a few hundred miles (a week or so)
- Always drain it hot or warm.

I believe that I filled it up with about half and half gear **** and Chrysler ATF+4 (it's what I had in the garage) and drove it gingerly around the neighborhood till the unit was hot and drained it, then filled it with RP ML 75w-140 and that's where I left it till now. I conveniently left that out of the original description since I figure someone might have freaked out reading it, interesting that this has become a "thing" on here now.

Great job on installing a drain plug, you're ahead of the game.

Seemed insane that there wasn't one. I tried using a suction setup before that but I got nothing out and figured it couldn't be completely dry so a small, 1/4npt stainless magnetic drain plug got installed.

Beware, the capacity is 16-18oz. Actual capacity will be less than this range based on sludge content.

Beware of what? I don't think you can overfill it, and if it's filled up to the bottom of the fill plug it's as full as it's going to get.

2) Change your mixture to 2oz ATF with 14oz of 75w140.
- Run this for up to 15,000miles.
- Check and clean the fill plug magnet often, at least every oil change.
- Change if necessary.
- Always drain it hot or warm

This mixture is safe to run for this up to 15,000mi interval. You can run it permanently or just for a few changes as a flush, before changing to 100% 75w140.

Huh, I guess that's roughly where I'm at now. What kind of ATF? I realize you're adding it for the detergents, but different grades have different detergents and I'd imagine not all of them are mixable with gear **** (I don't know for sure)

- Make sure you vent is clear.

Where the heck is the vent? I guess I haven't looked hard enough, but I'm also a big boy and can barely get under my SHO on ramps

Running just gear oil will take many changes and many miles to dislodge the sludge, with less than thorough results. Also, the mixture will be very thick. That's where the ATF comes in.

The ATF will break down the sludge but also help keep the sludge/paste from thickening the fluid.

I've saved 2 ptus this way and they're both fine to this day.

Sent from my PH-1 using Tapatalk

I'm guessing that "safe for 15000" means that it won't break down for that long based on the rest of what you said?

 

[GrolarBear]

Yea what he said....btw I use AMSOIL ONLY.

I used to work at a speedshop and had 3 catastrophic failures within 600miles of putting Amsoil in something. Probably a coincidence but I stopped using it after that.

I typically use Royal Purple, even though I think that Redline might be a slightly superior product, but I have an engineer at RP that is willing to discuss and recommend things for unusual/off label applications, customer support like that makes all the difference.

 

[krewat]

The only thing I gotta say is when a company needs to use a pyramid scheme to market their products, run.

 

[Hebes10]

to keep the vent clear, could you blow compressed air into the fill hole (after draining but before filling)? or would that make a huge mess?

 

[FiveLeeter918]

to keep the vent clear, could you blow compressed air into the fill hole (after draining but before filling)? or would that make a huge mess?

the vent is just a hose with a pressure valve on top. look down the driver side of the engine and you'll see it secured to the block, just unclip it and pull it out. Stick an airgun to it and squeeze. Then just push it back on the ****** on top of the PTU when done.

 

[mrhighcaliber]

The only thing I gotta say is when a company needs to use a pyramid scheme to market their products, run.

Pyramid Schemes by definition are scams and are illegal.

Although it doesn't carry the same shock value; Multi Level Marketing strategy (MLM) is the correct terminology.

They share some surface similarities, but usually differ greatly depending on the company's actual strategy.

Sent from my PH-1 using Tapatalk

 

[mrhighcaliber]

Royal Purple Max Gear 75w-140 after what I'm guessing is about 10,000miles??? I have a hard time believing it.
Well do you have evidence of a leak?

Also, RP gear lubes are great if changed regularly, but analysis have shown they tend to thicken sooner than average according to some used oil analysis done from rear axles.

I use Amsoil in almost everything and in most of my customers vehicles.
But Redline 75w140 gear oils are the best in durability according to used oil analysis.

"Remembering better what I did last time, I stuck a tube in the filler and sprayed a bunch of brake clean in there, let that dry a little and then I flushed about 2 quarts of kero through it in 2 batches (one the first day, let it all drip and dry overnight, another quart the second day just to see how clean it was, came out as slightly grey looking Kero)"



"I believe that I filled it up with about half and half gear **** and Chrysler ATF+4 (it's what I had in the garage) and drove it gingerly around the neighborhood till the unit was hot and drained it, then filled it with RP ML 75w-140 and that's where I left it till now. I conveniently left that out of the original description since I figure someone might have freaked out reading it, interesting that this has become a "thing" on here now."

Great move. And you should be able to gently get up to and maintain highways speeds safely with this mix. Torque is only routed to the rear under moderate to aggressive acceration. Under light throttle it barely sends anything back, and cruising it routes nothing. Under those conditions it's just more or less free spinning, slinging the fluid around at high velocities.

Yep I understand completely, people freak out over everything they don't understand. Lol


"Seemed insane that there wasn't one. I tried using a suction setup before that but I got nothing out and figured it couldn't be completely dry so a small, 1/4npt stainless magnetic drain plug got installed."

Great move.

"Beware of what? I don't think you can overfill it, and if it's filled up to the bottom of the fill plug it's as full as it's going to get."

Beware of the fact that if sludge is indeed present, it may only take 8-12oz of the 16-18oz capacity before it's full.


"Huh, I guess that's roughly where I'm at now. What kind of ATF? I realize you're adding it for the detergents, but different grades have different detergents and I'd imagine not all of them are mixable with gear **** (I don't know for sure)"

I usually save used ATF that's not in terrible shape, for uses like this. Doesn't matter long as it's synthetic. ATF+4 is perfect. It's Very stable syn ATF.

Indeed. I'm more concerned with the solvency of the ATF and the fact that it's of a much lighter viscosity oil than the gear ****. Once the sludge in the case is dissolved, it will thicken the overall mixture greatly. The lighter ATF/Gear **** solution should balance this out.

"Where the heck is the vent? I guess I haven't looked hard enough, but I'm also a big boy and can barely get under my SHO on ramps"

On the top of the ptu. It's either a metal cap "jiggle valve" or a black tube that extends up the back of the trans depending on your year.


"I'm guessing that "safe for 15000" means that it won't break down for that long based on the rest of what you said?"
Correct!

Sent from my PH-1 using Tapatalk

 

[mrhighcaliber]

I totally effed up the above quotations. Lol My responses however, are inserted.

Sent from my PH-1 using Tapatalk

 

[SM105K]

I totally effed up the above quotations. Lol My responses however, are inserted.

Sent from my PH-1 using Tapatalk

Wait...what? You like Redline too?

 

[mrhighcaliber]

Wait...what? You like Redline too?

Lol. Of course. Great oils are Great oils...I look at oil analysis on everything...DSM, Subaru, VW, BMW, truck forums...what holds up, under what circumstances, and what doesn't.
Redline holds up and performs excellent. (Gear, Engine oil, trans fluids)
Amsoil holds up and performs excellent. (Gear, engine oils, trans fluids)
Royal Purple is just ok by comparison (gear oil and engine oil). Their XPS and XPR oils are really good tho.
Motuls offerings are excellent as well.

I could go on and on about oils, viscosities, additive pkgs, filters, ete.

Sent from my PH-1 using Tapatalk

 

[SM105K]

Lol. Of course. Great oils are Great oils...I look at oil analysis on everything...DSM, Subaru, VW, BMW, truck forums...what holds up, under what circumstances, and what doesn't.
Redline holds up and performs excellent. (Gear, Engine oil, trans fluids)
Amsoil holds up and performs excellent. (Gear, engine oils, trans fluids)
Royal Purple is just ok by comparison (gear oil and engine oil). Their XPS and XPR oils are really good tho.
Motuls offerings are excellent as well.

I could go on and on about oils, viscosities, additive pkgs, filters, ete.

Sent from my PH-1 using Tapatalk

I know you do brother. I have seen your posts in the past. I just like to shed light on things. You do have convinced to switch out my Mercon LV for Amsoil.

My favorite trans fluid by far was John Deere Hygaard. If I could run that in the 6F55 I would in a heart beat.

 

[Sgtmeatsauce1]

Bobstheoilguy.com I believe is the ultimate info source on ****. Great info!