01 Trans fluid / Filter

[tbsbiker2]

easy question 2001 Pathfinder with Automatic. 54,000 miles. I want to change the transmission fluid since it's several years old, BUT not sure if a drain and fill is enough or if I really need to also drop the pan and change the filter....is that REALLY necessary? Fluid seems fine right now, no shifting problems. Trying to gauge soing a simple preventative matinance against my usual OCD doing more than necessary! dealer wants $168 to do a "flush"...but Ive heard that may not be a great idea.

Thanks

Peter.

[Andrew224]

The flush isn't recommended and may cause problems. Service manual recommends the simple drain and refill. 54K isn't too bad. If it concerns you that much, do the drain and refill and then do it again in like 15K miles and then stick with every 30K miles after that.

Andrew

[tbsbiker2]

thanks thats what I was thinking. wanted to get some other thoughts. Peter

[Almatti]

Also really think about draining and refilling all of the drivetrain fluids. Just got the real BAD News on my 01 PF - front transfer case damaged. I have 114k miles on it. Just put new tires and new spark plugs 6 weeks ago. Was meaning to have the fluids/oils checked and changed at the same time. She was running great. Then last week, my son tells me that "the PF is vibrating at speeds over 45mph. He was right after I tested it. Severe vibration at 45-60 or so, a bit smoother at 70 mph, then decelerating the vibration increased until 40 mph, then totally smooth. Rotated the wheels, same thing. Not tire balancing. Local mechanic checked it out, thoght it was a bad driveshaft and U joint, BUT he could not unplug the transfer case to check the oil. That was NOT GOOD. Local Infiniti service shop just told me yesterday: Transfer case needs to be replaced. SOB !!. A/C Compressor is going bad, water pump chirping, and the timing belt should be replaced: $5,000 of work.... Check & change those fluids, and Do Not Shift to AUTO 4WD from 2 WD on the fly as the manual indicates is doable up to 50mph. Another trusted mechanic who moved away told me -"that's Nissan's way to get you into their service Bay.

[SixGuns]

Mechanically speaking, there is no harm that can come by shifting between 4x2 and 4x4 on the fly. If you have stock hubs, the front drivetrain is already moving at the same rate as the rear. All engaging 4x4 is doing is meshing the gears on the transfer case to allow power to be applied at the front wheels, instead of them just turning on their own. The only way you can damage the transfer case or your front running gear is if your rear tires are spinning (no traction) when you engage 4 wheel drive. At that point, the rear drivetrain is moving at a higher rate than the front and you can and will inflict damage.

In answer to the question, however - I've done flushes on domestic transmissions...never had a problem. But I don't know how weak the seals on these Nissan trannies are...you might cause damage to some seals, I dunno. But why replace the fluid if you're just going to contaminate that nice new fluid with old crap in the filter? btw, just dropping the pan and draining the fluid, you'll only get about 1/2 the ATF out. Unless you do a flush, I would reccomend getting 2 filters. Drain, swap, refill, drive 500 miles or so, drain, swap filter again and refill. Then again, I learned this stuff growing up wrenching on Chevys and Dodges...I also know if your rear end is noisy from worn gears, you can put sawdust in the diff to quiet the gears...Dunno that I'd do that on a Nissan, though...

[Andrew224]

The drain and refill method comes straight out of the service manual. If the transmission has been neglected and noticably dirty or burned fluid comes out, then you have other issues. Then I would consider dropping the pan to see what's in there. FYI on my QX4 transmission, there is a drain plug. I don't have to take the pan down like I've had to on other vehicles.

I checked the service manual and as far as I can see, there is an oil strainer screen in there, no filter per se. The screen really only prevents large (relative term) debris from being circulated through the transmission. If there is debris in there, you have other more serious problems that a fluid change will not correct.

I've yet to take my pan down so I can't say that I've seen what's there with my own eyes, but in my experience (with much older cars), you can take the screen (which is metal and is just a strainer screen) down, clean it off and put it back up there, it's not like an oil filter with an element. Nots aying you can do this on these transmissions, just saying. Maybe in some transmissions there are filters that need to be replaced at intervals, I've just never encountered one on the cars that I've had.

If anyone out there has actually taken the pan down on a Pathy / QX4 transmission and can say for sure if there is a replaceable filter, please chime in and enlighten us, I'd like to know.

Andrew

[Densetsu]

There is indeed a filter for the A/T. I replaced mine last summer because I bought my Pathy the winter before and had no idea what the service schedule was on it previously.

If the filter hasn't been changed before, I'd change it, since it's been eight years! I'd change the fluid every two years and the filter every four, though it really depends on how the A/T fluid looks when you drain it. Your call, you can probably get away with leaving it in... but a $40 filter is a lot cheaper than a new transmission.

[Almatti]

sixguns: Thanks for the info.... Just touched base with another Nissan Dealer says that if the Plug for the Transfer case is "frozen", they can't be responsible for the damage to the Transfer case. You beleive this Crap !!Man, Check those fluids, avoid this nightmare

[tbsbiker2]

Warmed up the truck, pulled the trans drain plug and dropped almost exactly 5 quarts (I measured to be sure I put the same back in)...it wasn't horrible but wasn't near as fresh pink as the new Nissan fluid I put back in...understanding it's just over half new with old fluid I can tell you and I'm sure this isn't my imagination it shifts much nicer and smoother. The fluid on the stick looks like new fluid now but I may go ahead and do another change out in the near future to get it closer to a full change over. Cost was $52 for 6 quarts of Nissan Matic D...vs $189 for the "flush" which I decided against.

Next is transfer case and diff...Thanks, I love working on my rig.

pete

[Chuck Tribolet]

Also really think about draining and refilling all of the drivetrain fluids. Just got the real BAD News on my 01 PF - front transfer case damaged. I have 114k miles on it. Just put new tires and new spark plugs 6 weeks ago. Was meaning to have the fluids/oils checked and changed at the same time. She was running great. Then last week, my son tells me that "the PF is vibrating at speeds over 45mph. He was right after I tested it. Severe vibration at 45-60 or so, a bit smoother at 70 mph, then decelerating the vibration increased until 40 mph, then totally smooth. Rotated the wheels, same thing. Not tire balancing. Local mechanic checked it out, thoght it was a bad driveshaft and U joint, BUT he could not unplug the transfer case to check the oil. That was NOT GOOD. Local Infiniti service shop just told me yesterday: Transfer case needs to be replaced. SOB !!. A/C Compressor is going bad, water pump chirping, and the timing belt should be replaced: $5,000 of work.... Check & change those fluids, and Do Not Shift to AUTO 4WD from 2 WD on the fly as the manual indicates is doable up to 50mph. Another trusted mechanic who moved away told me -"that's Nissan's way to get you into their service Bay.

GO FIND ANOTHER DEALER. The '01 PF has a timing CHAIN that should lastforever, not a belt. If they are lieing to you about that who know what elsethey are lying about.

[GRNMACHINE]

Anyone recommend Mobil 1 synth for trans fluid?? Also anyone able to get to the front diff to change? I did the rear diff last month, piece of cake. Could not see an easy way to get to the front diff plugs without a lift though. Any thoughts??

[CPS]

Chuck Tribolet, not all 01's had a 3.5. Some had a timing belt motor.

[GRNMACHINE]

Was able to change the fluid on the front diff. Considering having the dealer do the trans fuid change/fill with a new filter. Anyone know if Nissan uses synthetic?