Temperature Control (electric) - Manual Transaxle gearoil cooler

[Sodo]

I like your temps, cooler at 145 and fan at 150 but I wonder if they are too close for tolerances.

I'm planning to use an $18 INKBIRD to control the fan, then you can set it for other temps 'as you wish'. Maybe hidden back in the engine bay or under the van, don't need too many numbers on display.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[PDXnatv]

Also found this dual impute dual output temp controller that can be fine-tuned to run our pumps and cooler fans independently or simultaneously. Eliminates the need for thermoswitches and just relies on temp sensors. Thinking of adding a sensor to my front diff and using just one impute to run my pump and cooler simultaneously since I have already ordered the inline temp switch for the fan operation. this unit is not cheap but I bet it won't die when it is most needed.


https://www.dwyer-inst.com/Product/Temperature/Swi...literature

[Sodo]

I added a temp gauge to the front differential.
It's temperature behavior is "interesting" for a little while but it doesn't get 'hot'.
It takes something like 10 minutes to reach operating temp after you switch to 4wd. It runs about 10°F cooler than the transaxle.
I think that's what it was..... (this was back in 2021 van season). I do have pics of temps/speeds etc.
After the initial comparisons etc it became "less interesting" to a feller who's 'one-hand-clapping" (me).
It could become more interesting if a few observant fellers had front diff gauges, and a campfire.

Front diff has better cooling airflow than the transaxle, and it's R&P only, no gears or nearby 190°F engine.
The more interesting debate might be how much heat comes from the R&P, the stirring, and the VC slippage.
This would be better suited to the mutha decoupla thread..... than the "electric temperature control" thread.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[ALIKA T3]

[charleslabri]

could use that to power the fan and the pump eh?
so it kicks the pump and fan on at 140
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An example of my labor in action:
https://www.instagram.com/wileythewesty/

My Build Thread:
https://www.thesamba.com/vw/forum/viewtopic.php?t=730525&highlight=

[Sodo]

[charleslabri]

trust, but verify. I like the mantra.


Did you just go with an arduino? Did i miss that in the thread?
_________________
-------------------------------------------------
An example of my labor in action:
https://www.instagram.com/wileythewesty/

My Build Thread:
https://www.thesamba.com/vw/forum/viewtopic.php?t=730525&highlight=

[Sodo]

[jalan]

It's been three years now and 25,000 miles since I installed my transaxle cooler/filtering system. See previous posts for more details.

To reiterate; front grill mounted 10 row Derale stack plate cooler, BAT/Mocal pump, FSM 145 thermostat, Canton filter and mini Magnom. Inkbird controller/temp gauge.

It is interesting watching the temperature in different conditions. My controller is set to come on at 90 degrees in the winter and 80 in the summer. Once it comes on it runs continuously until the van is shut down. This avoids the possible problem of pumping cool oil on a hot gear.

With the FSM thermostat the cool oil in the cooler is slowly added to the flow. It is not dumped all at once into the circuit. You can see when it activates as the temperature drops by 3-5 degrees and then stabilizes.

The oil temperature has never topped 150 degrees, even on the hottest day and on a fully loaded long high speed up hill run. It has also never gotten hot when traveling back country roads at low speeds. On most trips it runs in the 130-140 degree range.

Some might wonder about the longevity of the gear pump. It is rated at 10,000 hours. At an average of just 30 mph 10,000 hours would take you 300,000 miles. I'll be stoked if my tranny goes that long without another rebuild. If it does I'll happily spend another $450 for a new gear pump.

I have also thought "what would happen if my pump pumped all the oil on the ground due to a system fault"? I like the idea of adding a low oil pressure warning light and will add one the next time I change my filter.

April '22 On the Alvord desert near the Alvord Hot Springs

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1989 Syncro Hardtop, 2.5 '07 Subaru
1991 Carat Hardtop
1995 High Top Eurovan Syncro

[nmerrill]

I installed a low oil pressure switch into the lines after the pump, and connected it to a dash LED.
Switch was a Bosch 0986344082 - supposed to be 0.25 Bar and NC
Unfortunately, it seems there is not enough pressure in the lines to keep this switch open. It was a gamble, I lost.
So, I'm not trying to find another way to signal a loss of oil in the trans.
Open to suggestions!

[MarkWard]

I would be surprised to see any pressure other than friction loss on an open system. My quick change rear uses a gear pump driven by the input shaft. The lines are dash 6 but have restrictions built into the returns.

You might try adding a restriction in your return. Flow shouldn’t be impacted enough to notice and your gauge might come to life.
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[DanHoug]

there's lots of flow switches in various configurations... the basic design being a thru fitting with a paddle in the stream that gets forced closed/open when flow is present. magnetic reed switches inside sealed tubes do all contacting so they last a long time.

but on a splash lubed system, yes you have pump assist but for cooling/filtering, level is more critical than pressure or flow. those two parameters, pressure and flow, don't start dropping until the level is past dangerously low.

to do it right with NASA levels of money, a Lexan trans case should be mocked up to observe standing wave patterns of gear oil in the case. then a paddle flow sensor could be inserted in the exact right place to receive gear oil whip while moving.

n'yeah, some things are best when good enough. just do periodic inspections and trust the hardware.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[Sodo]

[nmerrill]

Well, my filer is in pump return, and is 100 micron/magnetic - chunk protection.
If I squeeze the pump output lines it produces enough restriction to open the switch.
I'm not keen on reducing flow though the trans for the switch to work.

And, for the record, I'd rather have a warning light/buzzer rather than hubris over my engineering skills...

[Sodo]

So the 100 micron filter produces less than 3.6psi back pressure.

Starting this gearbox cooling project in 2016 it was all about the cooling.
Then with the data, found that well-built trannies don’t get very hot except at ~75mph+ and in the heat of summertime and pulling a grade. And 5.43s get hotter, 6.17 hotter yet.

I think most of the problem was people hanging a big engine on a worn out old gearbox then driving fast, heavy, far, in the summertime and destroying the old box.

Since then we’ve studied the overload aspect of the problem and found that overloaded bearings last much longer in clean lubricant (obviously) so the focus has changed to filtering. But 10 micron is about the best you can get - but I’ll take it. Overloaded bearings need submicron filtration for any hope of longevity, but less than 2 microns is is where it starts to help. Where lots of the particles are smaller the oil film thickess (of cool/thick oil).

But you can barely get to 10 microns, so we’re back to “changing the oil”. But I settle it on the shelf until its crystal clear & re-use it. A manual final purification.

nmerrill your warning system will work if you change that 100 micron for a 10 micron. If you have the Weddle pump, it will still flow lots of oil. I like the Canton Racing long “10 micron” filter. The filter us about 6inches long and I run it thru “backwards “ so the stuff is on the outside where I can see it (if necessary).

Your desire for a warning system is popular, we’ve heard it many times. I even bought s 3.6psi switch for that reason but haven’t integrated it yet. I ran ‘extra wire” for that reason but never added it.

On the subject of “Control” though, the current plan is to run a 2-stage cycle where the pump tuerns on at 110F but the fan doesn’t turn on until 150F. To reduce the accumulation of “thermal cycles”.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[DanHoug]

[Sodo]

I "would"..... just haven't yet. I'm bummed that Swepco 201 is "so dark", it doesn't give that 'clear as honey' gratification that non-dyed oils offer.
Why so dark? The dark color makes the condition difficult to evaluate. I have Swepco 201 in the front diff, but not 'often' so haven't been to the 2nd cycle yet.

It's gone beyond 'proposal' for me.
Ultimate purity with almost "zero effort, zero cost", what more could a feller want?
Other than respect. I don't admit that I have "oil settling" ..... to just anyone, gotta keep lips sealed or they think you're just 'nuts'.


But I always have some gear oil 'sitting on the shelf' that's substantially cleaner than what was running in the gearbox 'yesterday'.
This is great fodder for the
Proposal:Settling metal fines out of gear oil that's still fresh thread.

Strange how the 'search' doesn't seem to work anymore.
Searching from Google outside" works much better than the internal "google search".
Soi I've included the ^^direct link^^
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[RolandD]

The D24T 6 cyl diesel vw/Volvo engine had a oil level sensor in the pan. I do not know how it worked, but could find a part number if someone wanted it.

Roland

[DanHoug]

as i mull this over, two things come to mind for an expensive transaxle...

one, some sort of static level measurement would be useful. can be pretty easily accomplished with an ultrasonic sensor or primitive float gauge. heck, even a sight glass, which many are made for transmissions that are robust. so this one is sorta 'easy'.

two, with external plumbing comes a greater chance of breakage. generally you'd know if you cracked a trans housing because of the great Thwack it would take. but a cracked pipe fitting/line is another matter. to that end, it seems a flow sensor in the post-filter line would be useful. it would:

- establish some baseline flows per temperature, always fun to watch the flow rate go up as the trans temp increases/filter resistance goes down. Geek Gauge.

- if there was a rupture in the exterior plumbing, a flow sensor would catch the trend if the sender was right before re-entering the trans. you would have to have awareness of the trends to make sense of the data but someone like yourself would be well tuned to the dynamics of the flow meter output. heck, it could be as simple as an LED that pulses with each rotor turn of the flow meter. fast blinky, good flow.

dunno. with something like a 1-30 liter per minute $6.90 flow sensor it sorta gets the wheels turning...
https://www.digikey.com/en/products/detail/seeed-technology-co-ltd/114991176/7387421
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[nmerrill]

These may fit the bill...

https://www.digikey.com/en/products/detail/honeywe...01/6056384

5000 series - down to 0.5 psi