Dexron II or III?

[texasmike]

I'm not sure what kind of fluid is in my 700R4 transmission. The shop manual recommends Dexron II. I have some Dexron III so would it hurt to top it off with it? Will the two types mix and what's the difference between them? As always..........thanks.

 

[dusterdude]

3 is all you can buy nowadays,you'll be alright

 

[bucket]

Actually, for several years now, there has been Dexron VI. It can be used as well.

 

[fast 99]

Get whatever you can find, all Dex will work. Went to 3 parts stores all I could find was Dex 6 for $11 a quart. What a rip.

 

[texasmike]

Thanks everyone, I have 1-1/2 quarts of III so I'm in good shape.

 

[DoubleDingo]

I don't have the 700r4, I have the th400 in my '81 Silverado and a AW4 in my '91 Cherokee, the th400 calls for Dexron II and so does the AW4, so I use Valvoline Dex/Merc V, it's the only non-synthetic I can find locally, and haven't had any problems running it either vehicle. If you end up not being able to find Dex III, you can always go with V.

 

[Bextreme04]

The 6L80 in my 2011 requires Dex VI and it's easier to just run all the same stuff in everything. Since my 4L80 and two TH400's can use either Dex VI or earlier, I usually either get the Valvoline MAXlife ATF from WalMart for $25/gal or I order the ACDelco Dex VI from amazon for about the same price.
https://www.walmart.com/ip/Valvolin...n2kwTaMdPvrwRxo_ki0aAkjQEALw_wcB&gclsrc=aw.ds

 

[Dutch Rutter]

I use DexIII in mine. No fluid related problems, I believe the trans builder guy told me he usually runs Dex VI in them which is compatible with DEXIII?

 

[82sbshortbed]

The 6L80 in my 2011 requires Dex VI and it's easier to just run all the same stuff in everything. Since my 4L80 and two TH400's can use either Dex VI or earlier, I usually either get the Valvoline MAXlife ATF from WalMart for $25/gal or I order the ACDelco Dex VI from amazon for about the same price.
https://www.walmart.com/ip/Valvolin...n2kwTaMdPvrwRxo_ki0aAkjQEALw_wcB&gclsrc=aw.ds

^this for me too. Just got 2gallons for 23 each at Walmart.

 

[Bextreme04]

I use DexIII in mine. No fluid related problems, I believe the trans builder guy told me he usually runs Dex VI in them which is compatible with DEXIII?

Dex VI is basically synthetic Dex III, so it functions the exact same, but holds up to heat much better.

 

[Octane]

Thanks everyone, I have 1-1/2 quarts of III so I'm in good shape.

I would run lll, never the Vl as it is a slightly diff viscosity, as what was said by some corvette tranny rebuilders anyway. YMMV. Something about VI being 26 viscosity and III being 30.2 or so. Thinner VI so more modern vehicles can hopefully satisfy mileage requirements of the enviro nuts, at the expense of longterm durability

 

[Matt69olds]

The crappiest fluid made today is superior to the best fluid 30 years ago. Don’t sweat the kind of fluid.

I use the Valvoline Max life synthetic in my vehicles. It’s around 33 bucks a gallon at Autozone. People have said it’s cheaper at Walmart, but I can never find it at my local Walmarts.

Either way, 30ish bucks a gallon for quality synthetic fluid is had to beat.

 

[My78truck]

I think i went ot NAPA and bought II at one point - before the tranny rebuild a few years ago which I believe they used synthetic - although they do not have it in the service notes....... Just like ol' dino oil, hard, if not non-existent to find. I still have my original flat top lifters. Somewhere I saw you can get old dino that is used for tractors. Have to look into that.

 

[AuroraGirl]

Actually, for several years now, there has been Dexron XI. It can be used as well.

VI you mean

 

[AuroraGirl]

I would run lll, never the Vl as it is a slightly diff viscosity, as what was said by some corvette tranny rebuilders anyway. YMMV. Something about VI being 26 viscosity and III being 30.2 or so. Thinner VI so more modern vehicles can hopefully satisfy mileage requirements of the enviro nuts, at the expense of longterm durability

I would avoid Dexron VI for the compatibility with seals problems more than viscosity. Dexron VI is thinner than Dexron III was, but when at operating temp Dexron VI is thicker. and its lifetime its more consistent than III which had a steep drop off once the fluid started to get a little into its service life.
Dexron III is only produced under one label "Manual Transmission and Transfer Case Fluid", any other product claiming to be Dex III is not actively monitored/licensed by GM, so it technically can be lie. But Valvoline ive hard has a good "universal dex/merc" that is good as far as fluid goes.