TheSamba.com :: View topic

Sat Feb 09, 2013 7:02 pm

The answer is in the post above yours. It comes out the bottom and back in at the top.

Sat Feb 09, 2013 10:36 pm

I too turned the engine over with the lines disconnected and fluid came out of the bottom hose. I hooked up my mocal tstat and external cooler a year ago and have had it work flawlessly for several thousand miles that would include hard driving conditions. Temp gauge on the pan is usually reads around 165 but will climb to 180 on 100 degree days while sustaining freeway speeds. Very happy all in all.

Sun Feb 10, 2013 11:23 am

Excellent, thank you guys.

Mods: possible to delete the above posts that contain conflicting information, for posterity?

Sat Jun 30, 2018 5:29 am

James 93SLC wrote: The answer is in the post above yours. It comes out the bottom and back in at the top.

So, :wink: Which port, ( top or bottom )
would be best to have a Oil Filter Located ?

I have an external cartridge oil filter.

I'm (guessing ;o) just before it re-enters the Transmission?

Also, I'm having trouble getting the fan to come on!

I have the:
Electric Fan Control, On 180 Degrees, Off 165 Degrees, Kit
DER-16730 from Summit.

My Question is; where should it be located
& does it matter?

I have it away from the trans next to the Fan,
and I'm wondering if the fan control
Isn't getting Hot Enough to activate the fan?

So, I'm thinking perhaps it should be next
to the Outlet (bottom ) of the Transmission ?

Location,,, Location :!: :idea: :shock: :lol:

Thanks!
John C...

Thu Aug 07, 2025 9:26 am

72wagun wrote: I ran across this thread while trying to determine how to hookup the thermostat on my Gowesty trans cooler kit. Since this was the only thread I could find with an answer I decided to call Gowesty to confirm this with them. They told me the opposite of the answer given here.

Gowesty said:

Top - Outlet
Bottom - Inlet

[Edit: See my later post below. I think the information above is incorrect now. I must have misunderstood what they were telling me. I'm sure they know what they are talking about.]

With two sources of conflicting information I decided to look for a third answer. I called http://www.germantransaxle.com in Bend Oregon. They rebuild these transaxles. I thought they should know how they work for sure. They confidently said that the top is the outlet, and the bottom is the inlet. Take it for what it's worth. I hope this helps others in the future.

This is an old thread I referred to when I was setting up my external trans cooler with my 010 Auto transaxle from a Vanagon in my Bus a few years ago.

After reading this thread, I originally thought that the trans fluid comes out the bottom fitting and returns through the top fitting and hooked my external thermostat & cooler up this way and have driven it for the last 40,000 kms.

However, I've finally tested mine by adding temperature sensors to both hoses from the top and bottom fittings. My findings are as above, what GoWesty said back in 2012:

Top - Outlet (hot fluid from the transaxle flowing out to the trans cooler to be cooled)
Bottom - Inlet (Trans fluid flowing back into the transaxle after being cooled by the trans cooler)

My external trans cooler is a 24" aluminum finned cooler with a 180 F (83C) thermostat. From my temp gauges, after driving 30 minutes at hwy speeds (75mph/120kph) with outside ambient temps around 85F (29C), the fluid coming out of the top fitting hovers around 240F (115C) and the fluid going back in through the bottom fitting is around 203F (95C).

I installed the sensors and just completed a 600 mile trip pulling a trailer on my way to the BC Interior which included a couple mountain passes. The fluid temp coming out of the top fitting went a fair bit higher while ascending the passes but after the cooler, the fluid temp going back in through the bottom fitting stayed under 248F/120C.

Having the inlet and outlets connected the opposite way seemed fine but it may have delayed the opening of the mechanical thermo valve in the thermostat, but once up to temp and open, the cooler would work the same.

The fluid temps seem a bit high when pulling the trailer but are fine when just driving the Bus without the trailer. I have a temp controlled fan cooled trans cooler that I may swap in to see if I can get those temps down, especially when pulling the trailer.

Thu Aug 07, 2025 2:25 pm

But, from the thread itself, and to add to what Kourt has posted in the past with this Port Operation.

Quote" Hi Atlas,

Well I pulled the transmission hoses off and cranked the engine, and sure enough the hose from the bottom port shot out fluid. It looks like my earlier posts just muddied the water. Sorry about that. Thanks for your help. ""

The ball and spring in the pump are at the bottom, the Center Hole in the pump, which aligns with the TOP port, also has the Drive Flange, aka Flower, and Pump shaft in it. I don't see how you could get the pump to discharge from the Top port with all that open space of the Drive Flange and Pump Shaft sticking right in there. Here's a couple of pictures from my Gallery

Thu Aug 07, 2025 3:00 pm

I thought the same thing and connected my external cooler thinking the same way (and drove it this way for 4+ years) but my temp gauge data tells me it's the other way.

"From my temp gauges, after driving 30 minutes at hwy speeds (75mph/120kph) with outside ambient temps around 85F (29C), the fluid coming out of the top fitting hovers around 240F (115C) and the fluid going back in through the bottom fitting is around 203F (95C)."

If the hot fluid comes out of the bottom fitting, it should be hotter than the fluid going back into the top fitting but it's the other way around with the hot fluid coming out of the top fitting and the cooler fluid going back into the bottom fitting.

My guess is that the ball and spring in the diagram above sit at the bottom fitting or somewhere in between the two and are there to stop the fluid from flowing out the bottom fitting when you first start up the engine and the transmission builds fluid pressure.

The initial spurt of fluid out of the bottom when cranking the engine that one of the people mentioned above, stops quickly and then as the pressure builds, the fluid flows out of the top fitting, through the cooler (original or external) and then back into the bottom fitting and the pressure buildup overcomes the spring tension and pushes the ball back allowing fluid to flow back into the transmission pan.

I installed the temp sensors in each hose so the hottest temp fluid should be coming out of the transmission and the fluid flowing back into the transmission should be cooler as it has passed through the hoses, thermostat and cooler before flowing back into the transmission.

I doubled checked with a handheld point and shoot gauge as well and the upper hose and fittings read hotter than the lower fittings and hose.

Thu Aug 07, 2025 3:13 pm

Red Beard wrote: OK darnit, searched for this info and found this thread, and it is conflicting and not confidence inspiring. Can someone who actually knows first hand post:

From which of the two holes in the transmission does ATF exit the transmission to go into the transmission cooler?

This is necessary information for those using an inline thermostat and/or a unidirectional inline filter.

(I have hoses for my external cooler waiting to be hooked up.)

Thanks!!!!!

IIRC, if you have the pan off you can just stick a wire through the ports and see which hole ends up in the case versus the oil pump.

Fri Aug 08, 2025 2:04 pm

Interesting regarding cold start bypassing flow out the bottom fitting. I’d have to trust the temp readings, but it would be nice to have someone place a clear section and video the flow for posterity. In a loop, probably doesn’t matter how the cooler is plumbed. For temp, I’d like to measure the fluid in the pan and call it a day. Systems with an external thermostat might be more critical to flow direction. A filter is best mounted in front of the cooler. I’d probably add my fan temp switch in the pan as well. Temp senders inline depending on type might affect flow.