About to fill my new 2004R. Builder says either Dexron/Mercon or synthetic, both are OK. I'm leaning towards synthetic...

Any recommendations?

Thanks!

I asked my builder that same question when I picked up my 400. He told me for a street-driven car use Dextron. GM has used it in millions of transmissions with good luck. Spend the extra money somewhere else.

Just priced synthetic....now I'm leaning to Dexron!!!!

The big thing is run the biggest cooler. Don't use the radiator side pan.

IMHO, the best synthetic juice for a GM auto tranny is from Allison-- $38.00/gallon. If you're stuck on synthetics.

A larger pan and a good cooler are the key to a long and happy life.

Mobil 1 synthetic. It meets Dexron requirements and can handle much higher temperatures than conventional atf's.