2nd Question of the day,
I've personally run all my 4L60E's with hydraulic fluid as it tightens up the converter, firms up the shifts as well as runs way cooler under load all great benefits if you can tune the trans to your liking. The 4+3s especially the early ones are all haunted with failure, so I was wondering if anyone has experimented with something other than ATF in them. It won't help with the bearing design faults but I think it could extend clutch lifetime and since something like AW36 is more viscous than ATF maybe bring pressures up for pumps on the way out or that have sealing problems. Any thoughts or ideas?

 

havnt tried that. the most deviant ive done is run atf where in my power steering which works great.

ive certainly noticed in the oilfield running equipment that guys will use whatever is around. i dont have the knowledge to mess with it in transmissions that have clutch packs etc.

 

I have never heard of anyone using "hydraulic fluid" in an auto.

But, as you stated, apparently it is being done. Some info to consider...

https://www.theturboforums.com/threa...of-atf.303735/

This one has a person that claims to be a pro that "forumulate various hydraulic fluids and ATFs"...
https://bobistheoilguy.com/forums/th...ission.196877/

The same pro, user "MolaKule", has some advice here...
https://bobistheoilguy.com/forums/th.../#post-1111352

Quote from a dragzine article, "Heads-up racing is a whole different world when it comes to ATF selection, and there are even racers who use hydraulic fluid inside their transmissions. Even though the transmission will still shift when using hydraulic fluid, there are some shortcomings to this — the primary being that these fluids aren’t designed to be exposed to high levels of heat and are prone to oxidation."
https://www.dragzine.com/features/lu...fluid-101-hpl/

When I search for C4 and hydraulics, I keep getting hits on Ford's "C4" trans and if it is about a C4 Corvette it is about clutch hydraulics.

I also emailed GearBoxVideo to get his opinion.
https://www.youtube.com/c/GearBoxVideo/featured

 

I was actually gonna email him once I got off work. As for the temp resistance, that may be true but it also reduces the heat produced so thats not a concern, in the 4l60e in my truck its dropped temps almost 60* towing. It does reduce the the lifetime and service period as it does not have as many detergents, so that will need taking care of.
As I said before, another down side it is raises line pressure so you can blow seals if you're not careful.

 

I just got a reply from 5speeds.com, "People need to stop thinking that using hydraulic fluid in a system that also runs gears is a good idea. Stick to the manufacturers recommended fluid. An automatic transmission is a little different than a hydraulic piston." ~Paul Cangialosi

 

That's an interesting take, I should have clarified earlier, I was talking specifically about John Deere Hy-Gard Transmission and Hydraulic Oil, and I was also only planning on putting it in the OD section, and running the recommended oil in the T10 of the trans.

The Hy-Gard is designed to be used in wet-clutch environments and wet-brake tractors and has the required friction modifiers to be able to function correctly, the 4+3 is the former of the two. He actually goes on to say...
Hy-Gard is rated at 9.4cSt @ 100C, which means it may actually be better for the bearings in the OD units, especially the early ones that suffered from all the failures.

While I do not wish to disagree with Paul, I think Hygard MAY help with all these issues except the washer issue. In the last case, the viscosity of the hydro fluid would mean that the lack of a seal would not have as big of an impact on volume lost due to the lack of a seal, which could translate into the carrier bearing being lubricated better, but I'm not familiar enough with the lubrication system of the 4+3 to know if that is the case in terms of the lubrication of the carrier bearing, it could be partially submerged, or splash lubricated or have oil fed to it.
It would definitely increase the volume the pump could move as the higher viscosity would "seal" the tolerances in the pump better than the thinner ATF, the higher volume would mean higher pressures on the clutch packs, which would decrease the heat created due to slippage and thus the holding torque of the lesser quantity of clutches in the early OD units. Personally, I have run it long enough in my truck (90k miles) to say that it is definitely the better option than ATF in the case of the 4L60 if you know how to adjust the ratios to get the desired slip in the TC. The only downside I can see is, like the 4l60, the shift into OD will be much firmer and quicker and will almost definitely require using the clutch to prevent damaging the driveline. I am gonna give it a try in my 4+3, it's going behind an LS so it may not last that long regardless, I don't want to bother Paul anymore but I may reach out and ask him about his opinions of the people running Hy-Gard or the likes in their autos.

 

You make a compelling case. Paul may have just given me the quick/general response to our question and I did not mention the particular product that you are considering. He replied to my email quickly, and perhaps he would enjoy discussing the finer points with you. Support@5speeds.com

 

The carrier that pretty much always fails is partially submerged iirc.

As far as the viscosity difference with pump sealing... the difference is marginal. A 2 cSt difference is not much. (Once it shears in use who knows. Mine has been okay so far.)

 

Will do like I said, I've run it in the trans in my truck for 90k miles now and I will never go back, usually, I'd say stick with the recommended oil but this one is too compelling not to try.

This is true, but that is also the viscosity at 100C, I think if the OD's oil were to get to 100C it's not an OD anymore and just a money pit. At 40C it's a difference of just around 15cSt, which is 150% that of ATFs at the same temp. I'd estimate the OD to run at maybe 50C but again I don't know enough about these units to say. On a 250 mile trip, with around 75 of them being in the mountains my 4l60 will hover around 49 to 60C with the Hy-Gard, and I very much doubt that the 4+3 generates enough heat for it to run similar temps.

 

Man, my 60e in the winter won't even run 60c with a trans cooler the size of a condenser. That's a pretty stout unit you're running.. I'd have to probe it next time I'm out and see what I get to but I agree. Probably in athe 180f range max.... thats about as low as I can get my radiator temp on a summer day and since it's oil to water it'll probably be about that... not like you have a TC spinning and generating heat. It's just the gear set and sprag iirc.

 

The cooler temps are just a bonus, I switched to Hy-Gard after a shop double sealed my trans filter and broke it at the neck. It was aggravated even more by the fact I was running 285/75r16s on the truck, didn't realize it until I went back to 265s that the little bump with the big tires was a hefty jolt with the "stock" ones. Dropped the pan, saw the clutch material and instantly knew it was shot. Tried the Hy-Gard as a bandaid and got a few more years out of it, but I just rebuilt a junkyard 4l65 and that'll be going in to the truck. It slips the top of 1st now and my fuel economy is just gone on a recent trip it averaged 12HwyMPG.It feels like its dragging the brakes on takeoff, and I used to be able to chirp the tires in second, now it struggles to spin the tires from a stop. Before it all, I think I used to run 205* with 80* ambient on the stock oil to water in the rad, but id have to check and see if I have any datalogs from that far back. I highly recommend everyone do Hy-Gard as their next change. If you only drain the pan in a 4l60 and do 4qts Hy-Gard 2qts ATF, it'll really make it shift nice. Can't wait to drive my truck with the rebuilt unit in it and Hy-Gard as the fill.

Anyway, Paul from 5speed.com says go with a Dexron oil since they aren't the cause of the issues in the 4+3 but I'm still gonna give it a shot, just because it isn't the cause doesn't mean something different won't help.