I was looking at this tranny cooler since my 95 bonnie has 135k miles with a stock tranny ne1 know much about these how much cooler would my tranny be with one of these and are they ez to install? Does my car come with a tranny cooler stock? http://cgi.ebay.com/ebaymotors/12000...spagenameZWDVW

That'll do just fine.

would something like that be better than getting a tranny cooler off a junkyard bonne/caddy and using that?

Yup. What if the junkyard trans cooler is full of 'trans death'?

well I would flush it really good, but as far as cooling goes.

Flushing may not be an option. Now that I've seen what my 93'* trans did to the trans core in the radiator, I'm a big fan of bypassing it and using a new cooler. New coolers aren't expensive.

Bill in your discussion with the tranny guys, did you happen to gain any information as to miminum normal operating temperatures for trans?

Remembering back, your trans cooler has a regulator of sorts on it to keep the temp at a certain level. When bolting on an external cooler should one be careful not to over cool the system and end up running it too cold, especially with winter coming?

Good point. I'm not sure a small 12k GVWR cooler like that would be an issue, as it is pretty close to the size of the OEM coolers on the SSE/SSEi with the 4T60E. Very few have trans temp gauges like I do to even monitor this. I know when I ran stacked doubles last winter and the winter before, I put a piece of perforated cardboard between the two coolers to preven harsh cold-shifts.

Trans temp can vary greatly from car to car even amongst seemingly identical Bonnevilles. In general, on a 70-80 day, most of our 4T60'* should run about 190°F in traffic. My new 28000gvwr cooler is thermostatically controlled, but it'* dictated by fluid viscosity so that at about 150°F, the fluid is not bypassing the main core, but travelling unrestricted through all of it.

I noted temps of about 160-180 degrees in the spring with my stock setup on the 95 SSEi from the scantool.

Like your setup, it seems that the engineers figured it to run around 160 coldest for proper operation.

Defintally a good idea to keep the temps down, im sure the 960+ mile treck i made this summer didn't help mine out at all, as it was slipping when it got really hot out..can cause nice clutch plate warpage heheh.
I'd consider an another cooler, but the only thing is, temps dont usually get about 85 here in the summer, with my drilled 180 coolant Tstat, im usually good to go.