Transmission Fluid Question

[VPC20HD]

Hello,

I have an 82' C20 that has the TH400 3-speed auto.

I added a quart of Dexron 4 and after, I realized my truck needs Dexron 2.

Is Dexron 4 acceptable or do I need to do a complete transmission fluid change to Dexron 2?

 

[Memaloose]

You can always go up in number with the Dexron without any problem, you're good to go with what you did.

 

[Edelbrock]

You can always go up in number with the Dexron without any problem, you're good to go with what you did.

Agreed. From my understanding, you can always go up on the Dexron number, but never down below the minimum number. The higher numbers are just better versions of the lower numbers and are backwards comparable.

 

[Ricko1966]

Do not follow the logic that higher numbers are good,on any lubricant without double checking. A good example is GL5 80/90 gear oil,it destroys brass synchros in people's transmissions all the time people assume they can replace gl4 with gl5.

 

[VPC20HD]

I actually put Dexron 6. Got the Romain numerals mixed up. What I’ve been reading is that GM stated Dexron 6 is a replacement for Dexron 2. Can someone confirm this or had experience switching from 2 to 6? I’ve also read Dexron 2 is obsolete now and no one really makes it anymore.

 

[fast 99]

As far as I know Dex 6 is just a higher quality synthetic version and can be interchanged with dex 1,2 or 3. Usually don't use it as a replacement for the older versions because of higher cost. Oil is expensive enough.

 

[NickTransmissions]

Is Dexron 4 acceptable or do I need to do a complete transmission fluid change to Dexron 2?

what's Dexron 4?

Use DexMerc, Dex6 or Ford Type F

All prev versions of Dex apart from DexMec and Dex6 are obsolete and out of production, AFAIK.