Can I use 10/30 hydro fluid in a torque converter?

[rodekyll]

I am having temperature and pressure issues at low pump rpm. My system uses a simple torque converter/fluid coupling to get power from the engine to the road -- no automatic transmission valves or clutches/brakes. Just a fluid coupling. I'd like to try a multi-vis fluid to keep the pressure up at idle. Can I use a 10/30 hydraulic fluid instead of the dexron II it was originally spec'd for or the 5606A I'm currently using?

I posted the long form of this in the atf section. Hope it's ok to repeat it here for perhaps more forum input. Thanks for putting up with me.

 

[901Memphis]

The 5606A is a very thin fluid, I really thought that a synthetic ATF would have been a good idea.

 

[901Memphis]

Also are you going to post some pictures of this thing?

 

[rodekyll]

I figured out how to post pics and dropped a few into the other topic.

I'm not locked in to hydraulic fluid. If I was I'd not be asking folks who know better about this stuff for help. I know I'm ignorant in this area, and I'm willing to listen and try whatever the experts have a consensus about. I had shied away from atf only because of the same issues I'm having -- DexIII, Mercan and type F all heated up much faster than the 5606. I chalked it up to the additives -- friction modifiers and detergents -- and went with 5606 because it didn't have those things.

What synth atf would give me close to the same cold V as 5606, but much more on the hot side? How complete a purge do I need to perform to make the swap?

 

[901Memphis]

The Redline high temp Atf i linked in the beginning of the last thread is about twice the hot viscosity and still flows well in cold temps.


https://www.redlineoil.com/product.aspx?pid=54

 

[The_Eric]

Yeah wow, that is some thin stuff! I found a PDS of it online- it's definitely optimized for very cold weather with a crazy high viscosity index, low 140 degree flash point and a 100 degree centigrade viscosity of 5.5...

If it's fairing better than traditional ATF, then perhaps the AT is shearing in operation.

Im just spitballing here on the optimal viscosity so take that into account-
You could try an ISO 150 fluid since you have nothing other than a pump right? No wet clutches or anything of that sort in the converter? Also could try contacting Red Line and seeing what they have in the 15cst at 100c range.

 

[901Memphis]

The Redline high temp atf is a 10 cSt at 100C, I figured it was the first jump before going thicker

 

[rodekyll]

The redline hi-temp specs do seem better in the right places. One reason I need low v when cold is that the pump's drive piece was designed as a 6mm hex shaft. Commonly replaced with a piece of an allen wrench. They are in my opinion undersized, and they are known to round out under use, leaving the bike motionless and cooking fluid. So I'm trying to avoid overtaxing the drive piece. I simply can't afford to throw $700 into developing an external pump right now.

The 100c performance of this redline is 2x or better 5606A, and their claimed 70c hotter max temp appeals to me. If you can't cool it down, make it like being hot. I think the av stuff is 4.8 or less at 100c. 10 looks better. My only hesitation with redline is as I responded in the other topic, that I've have poor luck keeping the differential fluid in the differentials of a couple of machines now, and the 10/60 oil (yeah, that's what the factory says for weight) seems to lose low rpm pressure and heat up more after just a few thousand miles.

Do the friction modifiers and gl4 properties affect the torque converter? I don't need smooth shifting, I need a smooth fluid coupling.

Thanks for the continued conversation.

 

[The_Eric]

If Dexron II was originally spec'ed then it should still work- unless you're doing something radically different than what Guzzi originally did? Am I missing something?

Like I said in the other thread, I wonder if the metal particles you saw are the root cause of why you're losing hit pressure.

Lastly, if you're worried about Red Line ATF, don't be. They make some of the best fluids around, using some of the best base stocks out there. But if the pump or converter is eating itself alive, then no fluid is going to "fix" your problems.

 

[rodekyll]

Dexron II became unavailable in Sitka, AK some years ago. At that time we were not allowed to ship fluids here unless we had special permits, and I could not get the town's auto parts store to order me any. So I had to find something else. The 5606A was plentiful and cheap at the time, and in Alaska it worked well.

I am a little outside the box with my specific application. The torque converter was installed in a 580# 2-wheeler and powered by a 1-liter, 50hp engine with a manually selected 2-range gearbox. I now have a 1120# 3-wheeler, loaded to travel at 1600#. It's powered by a 1200cc engine putting out about 90hp and 90# torque. There is no gearbox.

I'm heading to town to see if I can get some readline hi-temp atf ordered.

 

[CT8]

On some models of Clark industrial transmissions 30 wt motor oil was used in their transmissions . I one put 40 wt in [it was a forklift in our rental fleet and the driver didn't notice any difference . This was in the San Francisco California so the pumping temps were never an issue. You need a cooler. Torque convertors csude the oil to heat up.