as the title says

 

I use Penzoil ATF with Dextron III. You shouldn't use synthetic fluid in your trans. The transmission, unlike the motor needs a litle bit of friction to run right and to get the most life outta it. I was told by all 3 shops I got quotes from before I rebuilt mine in Aug. All 3 agreed that I should run regular oil. They also mentiond something about the ingredients in dino oil.

I know a lot of guys here are running synthetic oil in their trans and I'm not saying that its wrong. But after I did a lot of research on the subject before spending 2k on it, I found that the score was 3-0 for dino oil.

good luck

 

Valvoline Durablend Dextron3/Mercon5. Costs a little more but worth it. Not all places carry it so call around. I found it at a local Pep Boys. Mercon 5 is the highest rating available.

 

thanks anyone else want to chime in?

 

I have whatever the local chevy dealer put in mine. Non-synthetic. My transmission will slip if I use synthetic.

 

I also prefer to run conventional Dexron III in there. There is just too much uncertainty with running synthetics in the 4L60E, I know at least one of the aftermarket torque convertor makers recommends against using synthetics.

What I like to do is get the fluid changed every year, but I alternate methods. One year I get the full flush done and then the next year I get the more traditional "pan drop/filter swap" method done (which only replaces about 40% of the fluid, but at least you get a new filter and pan gasket, plus they clean the pan magnet)

I figure this method should help my trans live until hopefully the 150-200k mark. It's at 95k now and still works perfectly. I bought the car used with 56k on it and know for sure the fluid was changed at least once by the previous owner too.

 

Ditto that one, Penzoil DexIII here too

 

Tritto that.

I've heard some horror stories about synthetic and the b&m trick shift fluid, so I'd stay away from those...

 

Valvoline Maxxlife. Works a whole lot better than the Mobil 1 I had in there before.

 

ditto here, i used that one too

 

Royal Purple ATF...It hasn't even been 500 miles and it's getting checked this week to see if the fluid has been leaking. I'll post again with a yeah or nay.

I had the dealership stuff in there for about 50,000 miles no change or filter drop or anything. Drove it hard didn't lose a drop