I'm sure those who like to experiment have plenty of qualifications than the Toyota Engineers who designed and BUILT the Toyota T-IV transmissions.

Well... it's not that clear. Toyota doesn't build their own ATs. Aisin Warner builds ATs for 'yota and others. AW started as a joint venture from Toyota and Borg-Warner years ago but their trans have shown up in Jeeps, Volvos, others, their T-cases in many a domestic 4x4. Yet each automaker sticks their own label on the ATF bottle. T-IV is rebadged mobile fluid. As I stated above, it is not the same chem as Dex. Undummy is likely right, more addies for longer life, but also to work with the paper material used in their newer clutches and the partial lockup TCs that rub constantly until a speed is met for full lockup.

My experience is NO. I have a Lexus LS 400 that requires Type IV. Former owner put in Dexron III (regular drain and refill changes) and there was a shudder when tranny locks up into overdrive. The shudder feels that running over road dots. I put in 2 quarts of Type IV (drain and refill) and the shudder disappeared.

A lot of similar experiences in the Lexus forums.

Supposedly, this is a new, multi vehicle formula of Mobil 1 ATF. I don't know how it compares to the old one.

True! I was looking for T-IV back in April and Mobil 1 ATF came across. However, they CLEARLY STATED that it was not suitable for T-IV replacement. Since Mobil 3309 was very hard to find and cost the same as T-IV. I went with T-IV.

Same thing for Mobil Multi-vehicle ATF. [url=http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_Multi-Vehicle_ATF.aspx][/url]

I have done some research on this. JWS-3309/Type T/IV spec ATF is quite possibly VERY similar to Dexron III, with one exception- T/IV has more friction modifiers. T/IV is backwards compatible into transmissions that take Dexron III, however using a Dexron III ATF in a transmission that requires Type T/IV may (keyword may, likely will not) produce undesirable shift operation due to the lack of friction modifiers. This is why Universal ATF's exist and are not B.S., because you likely want those friction modifiers in the T/IV transmission, however the Dexron III transmission does not care. So they put them in the Universal ATF and it works fine in both.

My Tundra owners manual states T-IV only. Most Toyota dealers sell the stuff in case lots at very competitive prices. Being a cautious old [censored], I use what Toyota says use. I do a pan drain every 15,000 miles...it takes 4 quarts...and there's a drain plug on the pan. It's actually easier than changing the engine oil. Might be excessive, but @ 100,000 miles, the transmission shifts perfectly and the fluid is cherry- colored. We plan to keep the little pickup a quarter-million miles, and I fully expect the excellent A/Warner to easily last that distance with the above maintenance schedule. BTW, I've also installed an in-line Magnefine and do not ever plan to pull the pan.

I have been using RL D4 now for about 10,000 miles in my camry which specs T-IV without issue. I suspect maybe Redline is using some extra FM in D4? I have never experienced any shudder or poor shifting besides the "flare" that it has had since it was almost new that toyota states is "normal".

I think you've hit the nail on the head.

I used to buy into the notion that Chrysler's ATF+4 was a more highly friction modified ATF than Dexron or Mercon until I read the SAE paper detailing its development. That paper shows that the friction characteristics of the entire line of Chrysler ATFs (ATF+, ATF+2, ATF+3, and ATF+4) are all identical and are all essentially the same as the Dexron spec. In fact, in most owners manuals up until ATF+3 Chrysler listed Dexron as an appropriate substitute fluid if the ATF+ or ATF+2 wasn't available. The problem was that Dexron just wouldn't last in Chrysler's electronic 4-speed tranny. Chrysler needed a higher quality fluid that would retain its shift characteristics longer and that was the motive behind ATF+4. I suspect the same is true for Toyota and their switch to T-IV. (This is why most of the "universal" ATFs can list that they are for Dexron, ATF+4, and T-IV applications.)

Message from hate2work:


I don't wish to put out more speculation on T-IV, so I will just report what I have done so far. Last year (9/17/08) I did a drain/fill with 4.5 qts of PZ Multi-Vehicle ATF. I was able to get more fluid out because I removed the pan to clean the pan magnets and screen filter.

I ran the ATF through a cold winter where -10 to -15 F was the norm at night. The ATF has about 2k miles on it. 80% of the time is city driving, with a 20 mile round trip to work. I've never payed much attention to how the car shifts so I don't have a baseline with T-IV. But since the Pennzoil I payed more attention and the tranny shifts are smooth. No hard jolts... very faint most passengers wouldn't even notice. Pennzoil has served me well for the past 7 months. I have lost ~1 or 2 MPG but this is probably due winter fuel mix.

I guess I did this because local stealerships charge $8+ a qt for T-IV I seen it as low as $6.50 at others. But the Pennzoil works just as well if not better and there is always an abundant supply at Pepboys at a fix price $4 a qt. And there was nothing to lose from this test because I could have flushed the Pennzoil out of tranny felt bad. I'm going to leave the Pennzoil ATF in the tranny until I see something new I want to try.

I also like to add the Pennzoil Multi-Vehicle ATF is still the shaded of red as when it was fresh. No ATF foam or bubbles on the dipstick. The dipstick did not pick up any particles that would indicate a problem.

I'm also running Pennzoil Dex VI (GM Approved) in in my PS, which I've had in there about a year ago. Toyota calls for Dex III. But the fresh Dex VI seems to have smoothed the PS so I don't have to pull as hard on the wheel.

Getting off topic here. G-man, my real life experience tells me different. On my last Caravan (99?)with 3 speed tranny and ATF+3, a service garage did a pan drop/filter change and added Dexron at 50K and it immediately developed a shudder. I had them pump it all out and install +3 and it ran fine. I don't think this tranny had computer control to re-adjust and the original fluid was still in good condition.

Just my observation.

You guys that are installing non-OEM spec. fluids, please keep us informed how they do after you put 100k and more on them. We need to know if they are performing well for the long haul. Thanks.

Finally, I replaced ATF with pan drop and clean. Used Multivehicle Mobile 1 ATF and there is no difference in shifting whatsoever. Granted I have a 50/50 mixture of T-IV and Mobil 1.
It was worth the effort of removing and cleaning the tranny pan (at 60000 miles). Lot's of gray debris in the pan and filter. Drain and refill leaves it behind.

I agree with doitmyself. I bought my first new automatic equipped vehicle in 1970. (Plymouth Satellite 318)and have owned well over a dozen A/T equipped pcikups & cars, all bought new, in the years afterwards. I've used the mfg. specified fluid in every case, with only one problem: '89 Caprice 305 with the trouble-prone 200-R4 A/T...and even with that weak-knee unit, I got over 180,000 miles before overhauling it. They've all had periodic fluid & filter changes (agin, using Dexron, Mercon, T-IV--whatever the mfg. recommended) and all the others have given ZERO problems...and all were driven between 100K and 300K miles.
I'm leery of folks who recommend any fluid different than the transmission mfg. or vehicle owners' manual. because it's worked well for them for 1,000 to 75,000 miles. It's how well the A/T holds up over the long-haul that counts for many of us.

Can't agree here. The example you have is wrong fluid placed into wrong application. This thread is about evidence why T-IV is a glorified and in theory long life Dex III.

Besides, I used Mobil 1 ATF compatible with T-IV claimed by the same company who makes T-IV. 'Nuff said.