Tranny cooler
 

I am running a turbo 400 tranny and it dosent have a cooler should i get one or not? just wondering what my options are

Yes definitly get a cooler. If you're racing and going rounds you'll want to keep temps consistant to be able to keep your ET's consistant.JMO

a trans guage is also a good idea

Without a cooler I'd say your cutting the life of a race tranny by a 1/3. Especially if your running a stall converter.

Cooler
 

The cooler you can keep the tranny, the longer it'll live and will be more consistent. A gauge is a wise investment, especially with a brake and high stall converter.

I have always heard a 20° temp drop doubles the life of the trans.

Yep, trans cooler... CHEAP INSURANCE.

Always. Synthetic fluid will also drop it 10-15˚.

one thing about synthetic,,,,, does it change any characteristics in the trans,,,shifting ,,trans brake response ???

Not usually unless you are using a cheap thin fluid before changing to synthetic. It should also perform more consistently.

Hydraulic Oil will drop the temp too. I run it but don't have a temp gauge.
Still looked new after a season of racing.

If you're not running a cooler, you should have the In and Out connections on the trans connected together to allow proper oil flow inside the trans. I had a TH400 in my Camaro and ran a pressure gauge rather than a temp gauge because a pressure drop is sudden and will allow you to shut down immediately while a temp rise is gradual and the trans can be f*&%ked before the temp looks like a problem.