Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Put in Dexron VI instead of Dexron III

Changed Transmission filter and fluid plus Slick 50 tranny on my 2002 Toyota 4 Runner SR5 3.4 with 206,962 on the OD.

The Fluid container with the Dexron VI stated that it was Okay for vehicle recommending the Dex III

I only drove it 121 miles since the change. Now I noticed a lurch when coasting into a turn today and wondered if the SLick 50 was a mistake or the Dex VI was a mistake.

I was told that the Dex VI was synthetic and only good for new tranny’s. So I bought a gallon of the Dex III and I’m going to change it out tomorrow.

Question is: Did the Dex VI cause any problems in the 121 miles I put on it AND will the Dex III help flush out most of that Dex VI ?

I’m thinking I’ll drive it another 100 miles and change it again.

What do you think?

Your 4 Runner should be using T-IV from the Toyota dealer, not Dexron (III or VI) or Slick 50.


Your vehicle calls for Dexron 3

Dexron 6 is backwards compatible, so you’re okay there, but it’s significantly more expensive

Leave the Dexron 6 in there. It is not causing any problems.

However, I’m not sure why you put in the slick 50.

I don’t think the slick 50 is doing any harm. In fact, I don’t think it’s doing anything at all.

1 Like

I was told the Synthetic can wear on the seals and stuff. The hesitation doesn’t happen all the time just sometimes when I’m coasting between speeds and going from let’s say 30 mph to 10 mph on a turn. Other than that the transmission works fine. I just don’t want to be the cause of any transmission problems.

I mean it does have over 200,000 on it. If it gets worse should I go new or rebuild?

Thanks for the advice. I’m hoping to take a road trip in September which totals about 4000 miles round trip. I’ve been pumping money into the well maintained truck and don’t want to have trouble down the road.

Thanks again!

You think I should get the T-IV from Toyota dealer instead of using other brand?

Note: The Dip Stick Reads - DEXRON II III

My bad, db4690 is correct. The T-IV was not required until 03. The Dexron VI is backward compatible with any application that calls for D-II or III, but it does add considerable cost to the fluid change when it is not required.

I have used the Slick50 for manual transmissions and it is slick, but I have not nor do I think I will ever use the stuff for automatic transmissions. I’m not saying that it is bad to use it, but automatics are kinda fussy about their fluids so I try to keep it pure and stick to the recommended variety.

How much fluid did u add during service? 4 qts? 6 qts? More?

I bought 4 qts Plus the Slick
I’ve decided to just drain the fluid from the plug and add the straight Dex III to the full line.
Early before the sun comes up. It’s been brutally hot down here lately.
Thanks to everyone for your responses!!


Please let us know how it turns out

At 206K miles, most automatics are on borrowed time…Was this the first fluid change?

" Now I noticed a lurch when coasting into a turn today and wondered if the SLick 50 was a mistake or the Dex VI was a mistake."

Are you sure it’s the transmission that’s causing the lurch? Please define “lurch”…

never use these magic elixirs in cars. you want super slippery motor oil, i assume. but the trans works by having a certain level of friction on the clutch discs and bands so i would think any alteration of those slip properties would not be good. usually a slipping trans is a bad thing. hmm, maybe always?

Caddyman. I cannot believe that you don’t know what a Lurch is…

1 Like

With most machinery that has oil lubrication, the more slippery, the better. This is not true in automatic transmissions since the clutches are soaked on the trans fluid. The clutches are depending on the correct fluid characteristics to help them engage and disengage properly. I would only go with the manufacturer specified fluid and get rid of the slick 50.

5 year old thread revived by Jeff for some reason beyond me.

ironically i commented on this post back than and my kid just bought a 97 4runner. dont know why he wants a 20yr old rig. he has a 2015 grand cherokee.