New Manual Transaxle How Hot?

[Syncro Jael]

Just installed the AA Transaxle. How hot is a normal operating temperature?
I shot it with a temperature gun and it is running from 170 at the bell housing and 125 at the decoupler. Dead center at the output flanges is 148.

Is this normal wirh outside temps at 54 degrees?
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[joseph928]

Here you go! Mine are close to these. 160 hot most of the time less :
Some data from Alaric
http://www.thesamba.com/vw/forum/viewtopic.php?p=6123272#6123272

this is with a bad tranny cooler pump:
> I noticed the trans temp rising on the highway back from High Point NC. 185deg at 70mph so I had to slow down to 60mph to keep it at 160deg

this is with a properly working tranny cooler pump:
> I ran the van down the highway yesterday at 75mph and a 90 degrees out side and the trans temp never went past 135deg.

Some data from Bill (similar to Alarics temps with no cooler)
> Report: trans temp going and returning from NWMF (2,500mi) 160-175 degrees f.

Dereks input on target tranny temps:
>According to info posted by Derek Drew, 160 degrees F is when parts start to go out of spec.

Conclusion, Bill and Alaric's trannies, without a working tranny cooler, operate at or above 160F.

fwiw, anyone can check tranny temp with an IR gun, no sender installation required.

Bottom line is Alaric has developed a temperature control system that works. And my bet is most uncooled trannies see 160F+. At that temperature, I think motors with torque above 200ft lbs begin to move things around in ways that produce damage.

The reason Alaric sees tranny damage and Bill does not, is not that Alarics tranny runs hotter than Bills, its that Alarics motor has more torque than Bills.

According to Derek's 160F benchmark, both Alaric and Bill are experiencing heat expansion that puts the tranny tolerances out of spec. Once you get that, you need to apply torque in excess of 200ft lbs, to produce damage.

So my rule of thumb is, if you have more than 200ft lbs of torque, a tranny cooler can help.

Just my armchair analysis.
_________________
Where in the world are the The Lost Burritos?
_________________
1987 syncro westy tin top sun roof , GW2.3, rear locker, decoupler, Gary Lee tire rack & winch mount, lift, south african grill, big brakes , rhein alloy ,15 BFG AT, Fiamma 10 foot awning ,140 watt rear 85 watt front solar , mppt, truckfridge, automatic fire extinguishing system, tencent oil cooler, And a RMW SS exhaust! - 1971 bug convertible 1776 engine- 2010 Subaru turbo - 1993 Toyota 4x4 truck - 1999 Harley 95 CI, big bore, Andrews cams . Also 80-84- vans. Stock 65 sunroof bug.

[Syncro Jael]

Thank you Thank you!
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[bluebus86]

[Syncro Jael]

I have been reading all the posts I can find on manual transmission temperatures and what is acceptable.

My son is on a visit and he has a bone stock 2.1 WBX and non locker transaxle in his 87 Syncro. He is fully loaded with gear.

I have a Subaru EJ22 1994 and a rebuilt AA locker transaxle in mine with about 1400 miles on it now. My Syncro is not loaded down.

We both drove the same distance about 50 miles and the outside temperature was about 60° and we were freeway driving at 65-70.

Once we stopped I got out and checked our tranny temps with an IR gun.
His was at 163° at the drivers side output shaft and mine was at 174°.

I have a new tranny, new gear lube and I followed him at the same speeds. I am wondering why I am running 10° over him?

Any ideas???

I have been checking transmission temps a lot now that I have read some of these threads. My rebuild has included the new aluminum gear housing, new aluminum main housing, AA main shaft retainer plate, and oiling plates. I have also read that unless you have an engine with more than 200fp of torque you shouldn't have any issues with tearing stuff up with temps over 160°. I have also noticed if I shoot the output flange or CV on either side the temp is about 20° hotter than the side of the aluminum case

I am also running Mobil Delvac 75/90. The same as Daryl told me he is running in his Syncro.

I am really after some of the expert opinions on what transaxle temps are acceptable and safe so I can make this tranny last for a long time.

I also have now installed a temperature gauge to monitor my tranny temps.
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[alijonny]

[hans j]

There has been speculation that engine conversions and adapter plates cause more heat transfer to the transmission, but I don't know. It cold be more related to power output?

I haven't measured with an IR gun in a while but the gauge for my trans takes a LONG time to even get up to the 150* area and I haven't seen it go above that yet. Normally it hangs around 120* or so. I also keep my speeds below 65 mph for the most part. I'm still planning my gear oil pump and filter pretty soon though since I know it's going to get hot outside!
_________________
1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181

[Syncro Jael]

[MarkWard]

There is case temperature and oil temperature. They can be different. The one wire temp sensors are going to read the hottest temp because they are using the threads as a ground for the circuit. So it could be reading the case temp not the lube temp.

I'd be curious to know the temp of the oil coming out of the case and the only way to do that would be with an inline temp sensor with a pump/cooler design. I have an electric transmission cooler pump on the race car. It is extremely loud. Not sure how it would be in a Vanagon. I have a temp sensor mounted on the discharge of the pump and a temp switch in the case to turn the pump on and off. I have a warning light to let me know when the pump is running.
_________________
☮️

[Syncro Jael]

[crazyvwvanman]

Did you by any chance take readings of the front diff temps on both vans when you measured the tranny temps? Do both vans have decouplers and if so were they both in the same mode?

Mark

[MarkWard]

[Steve M.]

On reading this thread I'm just thinking about cutting a bleach bottle in half from the top down and zip-tying it to an easy to reach spot underneath to use it as a scoop to see if it directs enough air to circulate around the gearbox to aid in cooling. More so you need a way for the air to get out too.
It would probably need some ducting as the air would probably just spill over the top end and not go upwards.

The trouble is after driving down some of the hot summer roads I did last summer I don't see it getting much cooler air up around it. It might help though!

[Syncro Jael]

Here is an update:

I have my transaxle temp gauge installed. I ran it down the freeway to get it up to about 130°, stopped got out my IR gun and shot the same spot on the case. I was off about 5°

I went back and looked at the gauge again and it had risen 4°. Shot with the IR gun and now they are the same temp .

Ambient Temperature outside was 59°
Mounted gauge read 135°
IR Gun read 135°

From what I am seeing I believe the case is cooling off as the airflow is being directed along the case. I have read on a thread here that it might be as beneficial to use air to help cool the transaxle. I have built a small air scoop on my skid plate to help force air under and into the main transaxle housing.

This is a good thing! Now this weekend I am making a rubber flap that should extend down when road speeds are high enough to direct a larger airflow around the transaxle. I got this idea from my Porsche, it has (2)two rubber flaps that extend when the car is up to speed to divert air across the inner CV joints. (YEAH THEY GET HOT). They use rubber in case they come in contact with anything on the road. So if you follow a 2000 or newer Porsche down the freeway, you will see these extended down.

_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[Jon_slider]

Here is a thread with lots of temperature readings

http://www.thesamba.com/vw/forum/viewtopic.php?t=558339

[hans j]

Mine has a thermal switch installed that will turn a circulating pump on at 150*. Gear oil should run at least 250*, but that's in anything that's not a vanagon transmission...

I'm good with running 150* on mine. If yours goes over that, maybe slow down if you are concerned with longevity of the trans.

Originally it's an over weight, underpowered vehicle designed in the late '70's when the national speed limit was 55 mph. It's definitely not a Porsche, and I don't drive mine like it is, I want mine to last...
_________________
1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181

[Jon_slider]

[Syncro Jael]

Jon_slider

Thanks for looking that up for me.

I did get a chance to speak with Matt at AA Transaxle. I asked him the same question "At what transaxle temp do I need to be concerned and back out of it?"

His response was if it is an older magnesium tranny 180° would be a concerning limit with anything other than the WBX in it that is the point where the pinion bearing will just drop in, so that is the point it can just move again.

With the Aluminum Main and Aluminum Gear housings 200° would be a point to take the load off. But he also said Daryl was really looking into the gear oils a lot before he left us. to evaluate acceptable working temperatures.

So I am running what Daryl had in his Syncro "Mobil Delvac".

I am going to stay in communication with Matt, he took his Syncro out with the Suby 2.5 and was going to put loads on it and check the tranny temps also and get back with me. Right now I am only 25 degrees from his limit and it is still only in the 60° range. What happens this summer at 100° +?

Thanks again to you all! This is a great place to be....
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[furrylittleotter]

[Mundopacheco]

Were you and your son running different wheel/tire packages, as in different diameters, contact patch, weights?