I have an early 1997 (produced 1996). The trans fill say MERCRON ONLY as does the owners manual. I have been using fluid that meets Mercron and Mercron V. I want to use synthetic fluid and Moble 1 make a Mercron only synthetic. I have read many post that says use Mercron V even in these early 4r70w transmissions. I am about to do the valve replacements and the Transgo kit. I really want to use what is best for my transmission.
Which should I use.
Anyone really know for sure. Please no guesses.
Thanks.

 

The '97 can go either way. It was filled with Mercon before it left the factory but will accept Mercon V if you don't mix the 2 fluids (meaning drain the transmission and torque converter).

You can use Mercon, Mercon V, or dual usage fluid in the '97 4R70W.

Any recommendation I make would be personal. Use whatever you want as long as it meets Mercon or Mercon V specifications.

 

Aj is right on the money. Assuming we are talking 4r70w auto trannies here. The '97s came factory filled with regular Mercon. So long as you don't mix the Mercon and Mercon V (ie get as much of the old stuff out as possible by draining the TC or having the unit flushed), you can use either. Mercon V is often suggested in the '97's to cure any shuddering problems you might be having.

Mobil 1 syn ATF will be fine in the '97 tranny. It won't work in models that call for Mercon V on the dipstick(sometime after '97).

As far as a recommendation, I have been happy with Valvoline Durablend ATF - meets Mercon and Mercon V standards.