Buying and Installing a Transmission Cooler W123 - PeachParts Mercedes-Benz Forum

biopete · #1 02-22-2006, 03:20 PM

Hi all. I searched all threads with "Transmission Cooler" in title. Only 15 of them. They do not answer my questions.

I am getting a tranny cooler to experiment with how my 123 pulls a small camping trailer. (Dont try to talk me out of it

)

I at first wanted to observe the temps of transmission with and without the cooler to see how effective it was. However, I realized the best time to install the cooler would be when changing the fluid and installing the temp sensor. And definitely before I go pickup the trailer. I am taking everyones word for it that a Tranny cooler will extend transmission life. Science will have to wait until I can bypass the tranny cooler.

Questions I have are :

1) what performance cooler I should buy . The best I can that I can fit under the hood?

2) Does anyone have Pics of an installation on a W123. Or where is best place to mount it?

Here are a whole bunch to choose from.
http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=10535&parentCategoryId=10529&langId=-1

And here are B&M ones I'm looking at.

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=17689&parentCategoryId=10535&langId=-1

The 11x6x1.5 inch one seems like it would fit under the hood easy enough. Its rated at 24,000 GVW .

Thanks for any help and I will post story and installation pics here. (I promise

).

Al Magaloff · #2 02-22-2006, 07:31 PM

Tranny cooler should be placed first thing out in front of the radiator. I would never be satisfied with a cooler that uses neopreme hoses, hose clamps and barbed fittings. I would use something like the B&M Super cooler, with pipe thread inlets. Then stainless braided line to the tranny, or hard line with inverted flare fittings, to pipe thread into the cooler.

engatwork · #3 02-22-2006, 09:02 PM

What's wrong with the cooler that is already in place?

SD Blue · #4 02-22-2006, 09:13 PM

From the size of the "cooler" already in place, I would lay odds that it is more for bringing the tranny up to operating temp quicker and minor cooling at summer temps.

An external cooler is definitely a good idea, and a must for towing in any kind of heat, especially for a transmission with such a small fluid capacity. An extra electric fan would probably be a good investment also.

sailor15015 · #5 02-22-2006, 09:21 PM

Why would a cooler serve to heat it up faster?

SD Blue · #6 02-22-2006, 09:39 PM

Because the factory tranny cooler runs through the bottom of the radiator and transfers heat from the coolant.

Wasuchi · #7 02-22-2006, 09:51 PM

I would use one of these if I thought cooling was going to be a real problem. http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=21061&parentCategoryId=10535&langId=-1

t walgamuth · #8 02-22-2006, 10:05 PM

cooler out front wherever you can that air will flow thru. the benz tranny is pretty rugged, so if it is in good condition it will be fine as long as you keep an eye on the temp. i have seen 123s pulling small travel trailers. the wagon is ideal with the leveling system.

tom w

biopete · #9 02-22-2006, 10:41 PM

Quote:

Originally Posted by Wasuchi

I would use one of these if I thought cooling was going to be a real problem. http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=21061&parentCategoryId=10535&langId=-1

Thanks everyonen,

If "Front" is front . . .
The above link looks exactly like my AC condensor system. Radiator thing in Front of radiator and an auxilary fan attached. Could I use it ?

If not, how will I fit cooler there? Do I need to kill he AC (It does not work now but my wife would like it.) ? Should I replace the condesor with trans cooler?

Is "front" on the engine side of the radiator?

biopete · #10 02-22-2006, 10:55 PM

Quote:

Originally Posted by engatwork

What's wrong with the cooler that is already in place?

I do not know. Maybe nothing. I just read some on how it is not too great of a cooler and an auxillary one would help. I plan on testing sometime with my temp gauge. IE,

!) Bypass aux cooler , observe "natural" temp
2) Bypass aux cooler, observe heavy load temp.
3) Hook up cooler, observe natural temp,
4) .. .

you get pic. But I dont want to hurt my tranny ( I think it may be the best part of the car

) just because I was suspicious of the satus quo. I would rather fork out $50.00 now and hook up cooler and then experiment later.

EDIT: By hurting tranny I mean, I have to go pick up 1000 lb trailer and drive 330 miles back with it -- From St Louis Missouri to Nashville, TN,. If that short distance wont hurt it, I'm all ears.

thanks

#11 02-23-2006, 03:16 AM

I towed a rabbit convertible over 200 miles with my 300SD in its modified (higher power) form. The rabbit weighed 2850lbs. I was traveling at about 70-80MPH the whole way, watching the pyro and flying down the road using 3rd and 4th gear. I have also towed a Type III VW (whatever curb weight that is) for about 40-50 miles with no problems.

Stock tranny cooler. The transmission fluid (when I recent changed it) was a tad on the darker side of things so I am seriously considering an external cooler to go along with my intercooler water system radiator. Since I was inside the tranny looking at other stuff, I could not find any evidence of damage to internal components and the car still shifts firm (no noticeable change).

If I were you, and you simply had to haul this 1000lb trailer 330 miles and not much more, I would change the fluid before you left (maybe the filter too) then just go...

While the tranny temps are much warmer when pulling a load, 1000lb is the same as the car fully loaded with passengers and some luggage. While it may not be the best for the transmission, I assume that most of your trip would be just 4th gear driving along? If so...the clutches/bands don't care if the fluid is too hot or not when locked on/off in 4th gear.

If you regularly plan on pulling a trailer, then I would defintely consider a cooler sooner or later. The trannies are pretty robust

Al Magaloff · #12 02-23-2006, 05:10 AM

Biopete, the aux tranny cooler won't need the fan.You can have your AC and a tranny cooler. The tranny cooler may have to be mounted out in front of the MBZ aux fan, though. Pick a cooler you like, cut a piece of cardboard to the dimensions of the cooler, and see what fits where, and what you will need to mount it.

#13 02-23-2006, 05:18 AM

You should not need a fan. When it's working hard (the tranny) you should be moving fast enough for good airflow.

BobK · #14 02-23-2006, 07:59 AM

Get a stack-plate cooler. They have much more cooling per square inch of cooler. BTW, a transmission makes the most heat when it is not moving or barely moving. Stopping, starting and backing up make the most heat. Just ask any RV owner.

t walgamuth · #15 02-23-2006, 08:54 AM

a stack a plate is, but i dont believe that it is true that trannys make the most heat when sitting still and jockying around.

they get fried under highway conditions. the max heat is while driving down the highway pushing a lot of air around the boxy shapes of the rv. if you are pulling a small trailer like a flat bed you prob dont need an aux cooler. but they never will hurt you unless the lines leak and you lose all fluid.

tom w