Oil cooler

leave the oil cooler alone... engine oil does just fine at engine temps (195-210F), but ATF starts to cook at around 200F or so.

-Bret

But the tranny is full of castrol syn-torq.

doesn't matter, don't let ATF get routinely above 200F, otherwise it and your transmission's life will be drastically shortened. this is the reason why everyone screams "GET AN EXTERNAL COOLER!!" for the trans.

-Bret

What is the best aux temp guage to get and where is the best locaton. 02 Sil Ext cab 5.3 4l60e

I have an autometer electrical gauge with the sender installed in the pressure test port (700r4/4l60). this will give you a more "weighted" temp response than putting the sender inline with the fluid out line. it's matter of preference really, if you want to see it go up and down as you lock and unlock the convertor, buy 2 3/8 comp to 3/8 NPT adapters and a 3/8 NPT tee ( the gauge will have the 3/8 to 1/8 NPT bushing), assemble the T, then cut into the upper (I think) fluid line coming out of the tranny and install the T. if you want to have a more weighted (and IMHO, more useful) response unscrew the pressure test port plug (driver's side above the shift linkage, 11MM head, 1/8 NPT thread) and thread in the sender. then it's simploy a matter of wiring it up. I have my gauge in an A pillar pod along with a mechanical oil pressure gauge (you wouldn't believe how inaccurate the factory gauge is).

HTH, Bret

Tranny is an NV 4500. On a side note, I read somewhere that this tranny was only available in 3/4 and 1 ton trucks, but my truck is a half ton. Does anyone know whats up?