Did anyone install a transmission cooler on 850?

Auto stores sell them but I have not seen a 3/8” ID hose system. I like to install one in front of the engine radiator. Radiators are usually built with 200 to 300 percent efficiency (i.e. if you cover 50 to 75 percent of it’s area, it can still operate without problem).

My transmission shifts a little hard, from 2nd to 3rd, as the fluid gets hotter. Adding a cooler may help keeping the fluid temperature right or bellow the operating temperature. I hard that, drop in fluid pressure, how small that may be, due to the cooler, is acceptable.

Any experience will be appreciated. Thanks.

Ronjon
’93 850 (123k miles)

When the last time did you have your ATF replaced? at what milleage?
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Dennis

Hi Dennis,

I replace fluid every 10k miles and notice a smoother shift. I did that with my Honda Prelude and ran from 120k to 190k miles with the original transmission. Also, I drive gently, no hard acceleration, since it is an automatic.

Another reason I like to add the cooler is due to the inline transmission filter I put in. I timed the fluid flow with and without the filter and there was 100 to 150 ml less flow in 14 seconds with the filter installed. I did my best starting and stopping a stopwatch and the car and there may be some error due to that (.5 to 1.5 seconds).

I took the filter out and ran for few weeks, inspecting the radiator and upper cooling hose temperature by hand (similar temperature, humidity and same driving route/traffic during with or with out the filter).

I noticed hotter temperature on the upper cooling hose and the radiator with the filter installed. My guess would be about 5 to 10 degrees F hotter.

I realize that putting a filter will reduce metal particles move around the system, however, the system may run better without one (change in fluid pressure and heat build up due to flow restriction), but for the price of longevity.

Ronjon
’93 850

I was going to put one in, and the shop suggested that I don't. Number one is that is installed on the low pressure line, and there is already one there.. I think it may be a waste of $$$$. I just do a flush once a year...