External A727 transmission cooler pros and cons?

[class87]

From: ClydesdaleKevin  (Original Message)
Sent: 7/26/2005 10:50 PM

I'm having the radiator recored tomorrow.  I've read in other posts here, including Denisons's cool transmission cooling chart, that the cooler you keep a 727 tranny, the longer it lasts.

So, which will keep the tranny cooler?  Is the one in the bottom tank of the radiator efficient enough to cool the tranny?  I can have the shop bypass or remove/seal it if an external tranny cooler keeps the fluid cooler.

So, which is it, folks?  Which keeps the 727 tranny cooler?  The original internal bottom tank cooler, or an external finned cooler that mounts to the front of the radiator?

Thanks!

Kev



From: The_Pharaoh_Sob_amun

Sent: 7/27/2005 1:55 AM

Actually, having both is what you want.  You don't want to eliminate the OEM cooler.  Just run the lines so the coolers are in tandem.  I had this set-up on the WinneBeast and it saved my tranny on the way to the first NECWJ, and anyone who was there, knows how steep and long that hill was and how loaded down I was.  I;ll be installing the same set-up on the Pharaoh, but possibly with the dual engine/tranny oil cooler.

- Sob



From: denison
Sent: 7/27/2005 11:33 AM

The tranny cooler in the bottom of the radiator was fully adequate for us for over 10 years, including a trip up and over the Rockies. My radiator temperature sensor is in the pan, and would show me up to 190 or 200 on uphills in hot weather, and the long pull up to Loveland pass, 10,500 ft, it got up to about 250 or so â€" for less than 3 hours. The normal temperature was 170 to 190 on level ground. By the way, my engine oil temperature on that longest climb was about 280. It will get to 260 in the afternoon of a sunny day in the upper 90s in the shade, driving over black macadam at 60. If the sun goes under a cloud and the pavement cools off; so does the engine oil. It must lose a lot of its heat by radiation from the crankcase oil pan.
Sob is right; I would keep the original tranny “oil cooler”, since its other function is to get the oil warm in cold weather. If your tranny oil doesn’t get up to perhaps 150 or 160, it wont drive out the condensed water vapor that gets into it when cooling off overnight in wet/humid climates. Don’t forget; that chart tells you your tranny life would be drastically shortened if the fluid was at 300f for that entire distance. My tranny fluid temp gauge now reads 140 to 160, with rare readings of 170. In cool or cold weather, I will be putting a chunk of cardboard over the tranny cooler. I mounted my tranny cooler below the radiator, sort of behind the front bumper. It still seems to work fine, and almost none of the heat from that tranny cooler is seen by the radiator. If you can mount the auxillary cooler where it will have air flow, but not warm up the air going into the radiator, I would advise that. I know on some RVs it just isnt possible.
My auxillary cooler is the first thing the hot oil from the tranny sees, then it runs through the bottom of the radiator, and back to the tranny. The reason I added the aux.. cooler is because we were going to be towing cars behind the Winny, including one that weighs 3 tons, towing them to Texas as we do our retirement “move”..
My aux. cooler cost $60 at a local speed shop. Its finned part is about 7 by 9 inches, one row thick, the tubing making 6 passes through the fins. It came with the special tranny cooler hose, but I had to buy another length, due to where I mounted it. You will be able to see how I installed it at the meet. It is about as easy to install the cooler after you have everything back together, if your rubber hose connections between the radiator and the tranny fluid lines are not senile.



From: ClydesdaleKevin
Sent: 7/28/2005 8:18 PM

Thanks guys!  The shop is recoring the radiator with a 4 row core at 540-560 bucks.  Another hundred, and they'll add an external cooler in addition to the internal, and I think I'm gonna go for it.  Its not a huge cooler, and shouldn't hurt any seals or pumps. 

Kev



From: tatkin
Sent: 4/10/2006 9:30 PM

So ? I just stop down at the corner auto shop and ask for a tranny cooler ? Then wire it in ?



From: Phåråoh
Sent: 4/10/2006 11:59 PM

Pretty much.  You may need a couple of adapters to fit the existing lines and you don't want to by-pass the existing one in the bottom of the radiator.  Hook it up in with it.  The more cooling, the better.

- Sob



From: Phåråoh
Sent: 4/11/2006 12:03 AM

A note to refer to Denison's observations.  I don't see much additional benefit for the cost above the stock set-up unless you're doing a lot of mountain climbing or towing.

- Sob