Nissan matic D, Dex III, MerconV. ATF confusion

[sky jumper]

rethinking the ATF choice for my 99 nissan maxima and confusion abounds. owner's manual specs Nissan Matic D or Dex III. Valvoline Mercon V states it is Matic D compatible straight out of the bottle. but we know Dex III is not the same as MercV, so what gives?

Also, lubeguard black states it will convert Dex III into Nissan matic D (even though nissan seems to think Dex III will work fine on its own). and Amsoil universal ATF claims it will work with anything on wheels.

is this all just hand waving, or is there some rational explanation for this?

 

[The Critic]

Nissan MaticD is slightly more friction modified than Dex III, but the differences are so slight that Dex III can safely be substituted.

Dex III fluids have been dual-rated with the Mercon specification for a long time. Mercon-V is merely an "enhanced" version of Mercon with better low/high-temp performance, improved oxidative stability, and possibly improved dynamic friction retention and anti-shudder protection.

Friction Modifiers are "selective," so they'll respond differently to different types of materials depending on the material's porousity, surface roughness, etc.

 

[sky jumper]

interesting. would you say Valvo Mercon-V is slightly more FM than Dex III, allowing them to claim it's compatible with matic D, Z-1, etc? I'm thinking it may be a better match for me than Dex III. perhaps with a little lubeguard too.

Right now I have Amsoil universal in there. it seems ok, but the tranny sometimes hunts for the right gear and makes a howling noise when first engaged at cold start. I don't recall the howl with matic-D, but I've never liked how this car shifts. 1-2 is harsh. it hunts between 3&4. doesn't downshift to 1st unless you come to a complete stop (or floor it). I might add some lubeguard and see what happens. if no improvement I'm dumping the Amsoil and trying something else.

 

[The Critic]

The multi-vehicle ATFs contain a select range of friction modifiers that'll react differently depending on the type of material, hence the ability to "claim" compatibility in a variety of applications.

Some work well, some don't. For example, Amsoil and Pennzoil work well in Hondas, while Valvoline's Mercon-V does not.

People have had good results by using Mobil 1 ATF in Nissan transmissions without adding any additional additives.

 

[gfcrane]

I bought a new 2002 Maxima and decided to do a series of drains and fills on the AT at 8k miles. The manual called for, just like yours, the Nissan fluid or Dexron III. Nearly overdosed reading about fluids on this site but finally decided on Dexron III. Got 12 qts of Chevron about 2 yrs ago and added them four at a time over several weeks. There was nothing wrong with shifting before or after so figured I did the right thing.

 

[Shaman]

I may be the exception to the rule here, but I was told to use Dex 3 in a Nissan tranny, and basically killed the tranny by having it in for a week. I dumped it out, and the slam shifting subsided, but never stopped. Had to junk the car because the shifts were loosening the 220K KM car up, and didn't want to risk it.

 

[MaximaGuy]

I have Chevron Mercon V (which is also Dexron III approved) in my 2K max and it has never shifted this well. Good product.

 

[Max_Tl]

i have a '03 auto maxima-
there is no common answer to this ATF compatability issue, either here or on the nissan board (which i also belong).
I debated between the Amsoil & Mobil Syn ATF, came to the conclusion on the M1 (availability & slight price advantage)put it in about 1 year now 20,000km - no delay/hard shift issues.

then most recently switched my '01 pathfinder to M1 as well (bought used 130,000Km)-have noticed a smoother (butt dyno) shift on this one in particular.

 

[BearZDefect]

sky jumper, I can't recommend the best fluid but I have input on your other observations:

I've never liked how this car shifts. 1-2 is harsh.
I believe that is characteristic of this generation Maxima. If you are heavy on the throttle does it still seem harsh?

it hunts between 3&4. doesn't downshift to 1st unless you come to a complete stop (or floor it).
Refusal to downshift from 3 unless you completely stop or stomp it also seem to be characteristic of the programming on this transmission. I sure wish it were more willing to downshift to 2 when you slow down to a creep.

I might add some lubeguard and see what happens. if no improvement I'm dumping the Amsoil and trying something else.
Just my opinion, but unless it is worse than it was before there may be nothing wrong with your current fill.

 

[sky jumper]

thanks Bear. I've heard this transimission is a bit finicky. Some people claim flawless shifing with certain fluids, but that could be placebo.

the 1-2 hard shift - I think it's a bit smoother under heavy acceleration, although I rarely jump on it and stay on it through the shift. when I do get on it a bit I usually back off right away and it immediatly shifts to 2nd about as harshly as normal acceleration.

It actually does downshift to 2nd when slowing down, it just won't go to 1st unless you deliberately slow to a stop and wait for it to downshift. the 3&4 hunting is a separate thing - I usually turn O/D off to get around this when driving in the city.

overall I think the shifts are a bit better on the Amsoil than on the old dirty 60k mile matic D. but I don't like the howling at cold start, and I'd like better shifts if it's even possible with this tranny.

 

[BearZDefect]

I've been thinking about doing an exchange with M1 but probably won't try that until this fall having recently used Dexron IIIh with no change of behaviour. Meanwhile the price of ATF keeps going up...

In my experience the 1-2 shift is a bit harsh under light throttle but with more power the shift pressure seems better matched and push it hard enough and that lovely quick shift gets much longer than I like. There also appears to be some torque reduction programmed in there when the shift takes longer.

Mine is a 97 so the programming may be different, but it won't dowhshift from 3rd unless you almost stop (1mph) or stomp on it. Makes for a slow recovery of speed.

Mine doesn't hunt 3-4 but I turn OD off for a different reason: On mine this trans goes to OD and lock-up by 35mph choking the engine around 1,300rpm. I wish it would lock up in 3rd at 30mph when OD is off (good for town) but it only does so around 3,100rpm which may be nice for highway spurts but little else.

Who had the great idea that 4th without lock-up is better than 3rd with lock-up? Yes, smoother, but power killer and heat generator. This isn't a Cadillac, thank you.

Slush-box and auto-tragic are a great names for automatics, I prefer manual transmissions even with less engine power. Torque converters are only nice for the first 5mph or so and then they are nothing more than "power eaters" + "heat generators" to me.

unDummy may have some insight to offer us here.

 

[unDummy]

Nope, no insight here. BearzDefect covered it well.

Nissan 1-2 upshift is known to be harsh. Don't back off on the gas to control shift points. Let it shift on its own. You'll screw with the trannies ability to learn by manipulating the shift with the foot.

And, 1995 and newer Nissan transmission programming sucks. This is hard to believe 'cause the '85-1992ish Nissans had some of the best auto programming out there(those with pushbutton sport/auto/economy modes). Now, Nissan gives us nothing but 'pathetic shift mode'.
The tranny upshifts and stays in a higher gear for the MPG.
Could also be the adaptive programming, which is an issue if there is more than one driver for the vehicle. Try leaving the battery disconnected overnight.
Killing the OD during the city driving sure helps. But, you'll lose that MPG.

Skyjumper, did you do a complete flush or drain/refills with the Amsoil? How is the fluid level? and how are you checking it?

Do you have an extra ATF cooler? Nissans ATF tends to run hot and temp will affect shift quality.

And concerning filtration, since Nissan uses a pathetic screen, installing an aftermarket filter might help.
Drop the pan to clean the magnets. Iron and magnetized particles can collect/buildup and mess with solenoid function.

If you have a proactive dealer, there might be a software update.

 

[sky jumper]

yes I did a complete flush by disconnecting the cooler line and having my girlfriend run it through the gears while I added the Amsoil. Fluid level is right at the top of the full mark when hot and idleing in park. before the flush I did 2 drain/fills with ST dexIII and then dropped the pan and cleaned the magnets (they were coated in 1/8" of silvery goop). I tried taking out the filter screen, but could not access the top bolts (you have to take out the VB). I could not re-torque one of the filter nuts (because I could not reach the associated top bolt). I left it mediocre-tight and am wondering if that's why I get a howling noise when cold (fluid aeration pushing around the filter seal??). Anyway, I just sent a 10k ATF sample for analysis. depeding on what comes back I may switch fluids and install a filter.

 

[unDummy]

Nope, you didn't damage the pump. Your pan probably holds ~gallon. 2-quart increments gives PLENTY of wiggle room.

For Nissans, I typical drain the sump using the ATF drainplug, refill with 7 quarts, pump out ~6.5 quarts from the cooler line, and then top off with the last ~gallon. This is a very quick and effect ~3 gallon flush and takes about 15 minutes.

 

[unDummy]

So, you didn't tightened that nut? Try holding the bolt threads with pliers while using a small wrench/pliers on that nut. Or, notch the bolt for a screwdriver so you can tighten the nut.

I don't care for a cooler line disconnect and trying to add ATF at the same time. There is a risk of running the tranny dry which could add wear to the pump/bearings and cause that howl.

With ATF level full, start the vehicle to drain from the open cooler line. Then, shut it off to refill it completely. Repeat until happy.
I do not add & drain at the same time ever.

 

[sky jumper]

quote:

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Originally posted by unDummy:
...Try holding the bolt threads with pliers while using a small wrench/pliers on that nut. Or, notch the bolt for a screwdriver so you can tighten the nut.

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i used a needle nose vice grip to hold the threads, but it didn't work very well. notching it is a good idea, I may try that.

quote:

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I don't care for a cooler line disconnect and trying to add ATF at the same time. There is a risk of running the tranny dry which could add wear to the pump/bearings and cause that howl.

With ATF level full, start the vehicle to drain from the open cooler line. Then, shut it off to refill it completely. Repeat until happy.
I do not add & drain at the same time ever.

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it's better to just pump out the fluid without adding any in real time? seems like that would surely run it dry. I added two quarts at a time while she was shifting gears (took ~15 seconds), then had her kill the engine so I could check the level just to make sure it was above the full mark on the dipstick (which it normally is when the car is not running). repeated until 12 quarts went through. reconnected the cooler line, started, ran through the gears, and checked the level - it was almost dead on. do you think this could've damaged the pump?

 

[milwaukee]

I used supertech mercon/dexIII in my my 99 Infiniti G20 that calls for maticD with no adds and it works great.

No need for add on filtration. The "pathetic" screen does just fine. If your trans filter is actually filtering anything big enough to be filtered your trans is already shot.

 

[Anthony]

Ive used several different dex3s in my dads 01 supercharged crew cab since about 25k.

Truck now has 120k wih no trans problems at all.
I try to do a drain and fill every 10 to 15k.
Pan has never been dropped.

A good friend of mine has a 02 max and ive done 2 drain and fills with valvoline dex3 and his trans also operates fine.
All the nissan 4 speed autos should work fine with dex3.
Stick with nissans fluid for the later 5 speeds.

 

[unDummy]

Yep, I recommend the procedure for every automatic. Most have plenty of airspace for overfilling for flush purposes.

 

[sky jumper]

quote:

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Originally posted by unDummy:
For Nissans, I typical drain the sump using the ATF drainplug, refill with 7 quarts, pump out ~6.5 quarts from the cooler line, and then top off with the last ~gallon. This is a very quick and effect ~3 gallon flush and takes about 15 minutes.

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UD - would you reccommend the same procedure for a Honda civic?