Tranny coolers are not necessary in my opinion. We have had many GM 3.8'* and 3.1'* with the 4t60e and 4t65e trannies, and have never had a tranny fail. Not even in the GTP making 400hp. Unless you drive in a lot of stop and go traffic, or live in a warm climate (arizona, texas, etc.). The operational temperature for our trannies are 180-230 degrees. Anything below 180 is dangerous, and anything over 230 is dangerous. From my monitoring of the GTP on the Autotap, I have never seen it go over 200 degrees and that was with the full throttle runs along with a 1 hour drive at lots of different speeds, and 2 lane road passing, etc..., and it is making 400hp and 450ft.lbs torque. In my opinion coolers are not necessary. You can get one if you want, but we aren't going to put any on our cars in any point in the future. If it cools below 180 degrees it may do more harm than good.
1990 Maroon Grand Prix STE McLaren 3.1 Intercooled Turbo, 14.695 @ 94.49 on 12psi before cam/heads/etc.
1990 Bright Red Grand Prix McLaren 3.1 Intercooled Turbo, 14.819 @ 92.72, 189whp
1999 Grand Prix GT 9.75:1|K&N|160 tstat|No Ubend/Cat/Res|UD Pulleys|Ported M90/TB/Heads|XPZ|2.55"|Pacesetters|Stage 2 I/C. 12.442 @ 112.78
2000 Blue Bonneville SSEi Supercharged Gutted Airbox|K&N|3.4"|1.9'*|WP Pulley|Custom DHP|180*stat|41932'*|No Cat. 14.681 @ 94.80
2002 Dark Cherry Grand Prix GTP Supercharged & Intercooled
12.084 @ 114.38 w/1.743 60', 315.6whp, Fastest Stock Cam M90 GTP!
NOW XP CAMMED, 340.6whp with XP, stock heads, Gen 3 M90, 11.984 @ 115.84 w/1.750 60'!
Most HP Stock Heads Gen 3 M90 GTP!
2004 Red Monte SS Supercharged K&N|3.4 Pulley|1.9'*|180*stat|41919 plugs|3" dp|No cat/ubend|DHP|Shift Kit. 14.2 @ 98
GOT BOOST??? Friends dont let friends drive stock!