Noise when turning... Hmm?

[Jayce]

So now that we've seemed to have gotten the rear differential squared away (heard no noises whatsoever this morning) I'm curious about looking further into the other minor issue I noticed in the last few days that we've had bitter cold mornings. For the first mile when I drive the vehicle, it seems susceptible to trans slippage for the first mile. It's not bad, but enough to notice. Even if the engine doesn't begin to show that it's warm, just by driving about a mile away seems to eliminate any slipping. At that point I notice nothing and the transmission shifts acceptably. As the vehicle warms up for another 2 or 3 miles, it begins to shift smooth as butter. I checked the trans fluid and it appears to be a decent red color. When is this generally changed? Should I have done it now that I'm just beyond 50k?

Anyway, I could not get an accurate trans level reading because the manual says to get the engine at maximum temperature when idling, put the column into each gear for 5 seconds, put back in park, let it idle for another 3 minutes, then check the fluid level and take the lesser of the 2 readings on each side of the dipstick. That I won't be able to do till later, but like I said, I at least got to see the color of the fluid which seemed to look good.

Aside from the obvious causing an automatic transmission to slip (bad transmission), what else can I look at as being the reason for slipping but only when cold? I feel like a fish out of water since the primary vehicle I've driven has been a stick shift one. I have yet to understand this new fangled automatic shifting of gears jazz.

 

[C0RR0SIVE]

Slippage while cold, and only while cold (way too cold) is normally the fluid being too thick, which results in there not being enough pressure in your transmission due to the thickness. Where about in the world you live? Depending on your climate you should probably let your engine get warm before driving it, once the water starts moving around, the transmission fluid will get warmed up nicely since transmissions pump fluid to the radiator to be cooled by the engine coolant, or in this case, to be warmed up a bit.

 

[Jayce]

I live in Pennsylvania. Far from being Alaska, but also far from being Florida. Recently we've had a couple shocking dips in temperature. Two days before Christmas Eve we were rockin out @ 56*F, but a day later we were in the low 20's. I'm not sure how this translates to cold vs vehicle operation... I know I should start the vehicle and let it warm up, but while I was on the path of getting certain maintenance things up to speed I began to wonder if this was enough to be concerned about since I did, after all, notice it more than once when I drive the car after sitting throughout an entire cold night and being started and driven early that morning. I guess it's not far fetched, since in my Elantra (5 spd) I can hardly get it in 2nd gear unless I really baby the thing and let it warm up a few minutes. But even still, I wasn't sure if a slipping transmission was along the lines of "normal" when you're in colder weather.

For the record, the transmission's shifting capabilities would be unrelated to the differential I've just serviced, right? I would think the transmission would be controlling the front of the vehicle majority of the time unless the AWD kicks in the rear differential to help out. I'm just trying to isolate in my mind how related/unrelated they are.

 

[C0RR0SIVE]

Differential is un-related to transmission. 20F on old fluid is enough if it's worn out to cause it to get really thick compared to how it should be, and cause a loss of pressure, thus causing a slip feel. An auto works by pressing clutch bands together, it takes a great deal of pressure to do this, and to keep them from just spinning around each other, thus resulting in a slip. Excessive slipping, or driving like this can cause abnormally high wear on the bands, and cause your transmission to just give out, requiring a rebuild in the future, this is normally all that goes wrong in an auto is the clutch packs being worn out, just like the clutch in a stick shift.

Also, if your transmission has a filter, and it's partially clogged (main reason for required service even with good fluid at a certain mileage is due to clutch material clogging filters, clutch wear will ALWAYS happen, and theres a pretty good idea of how fast they get worn and can clog filters) and the cold has made the fluid a bit thicker, can cause low pressure, which results in slippage, and in worst case, burns up the pump that pumps transmission fluid. Just note, if your car has an actual paper filter in the transmission, a flush can actually make a clog worse on the filter if the filter is not changed out, this is possibly why they did a flush twice on some cars, as there was excessive clutch material, and they clogged the new filter during a flush, thus resulting in another flush needing to be done. So find out if you have a paper filter, because the filters say change at 10k miles, dealers say change at 30-60k miles, I always go by the filter as they are paper. But I also know newer cars just use a simple screen as a large particle filter, and they dont employ a paper filter at all.

Shifting capabilities would be unrelated to your differential, unless your front differential is sitting in the same fluid that your transmission uses, which it shouldn't, it should be using a heavy gear lube.

 

[Jayce]

Hm, good info. Appreciate it. In an effort to keep the thing running in nothing-short-of-fantastic-shape, what should my next plan of action be? I'm unsure of the status of the filter. I would think it'd be the factory filter since last night's maintenance repair was at the rear differential and not up front with the transmission. I would assume changing the fluid would be the way to go. I just checked it and the fluid level was good, however the color looked to be in the halfway mark of red and brown. I'm thinking it'd be wise to just have it done, especially since a lot of reading online suggests to change the transmission fluid around 50k anyway.

I'm looking online @ automd.com and I'm seeing an estimated cost of 43 to do it myself and 155 for a shop to do it. How much are transmission filters supposed to run? A shop I called said 139 for fluid change and I asked if that was with filter. The woman, who sounded irritated she had to get up from her desk to retrieve an answer for me, came back with 250 + tax with fluid and filter.

I'd love to try it myself but as someone who's never done this before, it's a little nerve racking. If it were an oil change, sign me up, I've done hundreds of those. Might be worth looking into though... I assume it's just... drop the pan, drain the fluid, wipe up the pan, reinstall the pan/filter, put new fluid in and call it a day?

EDIT - So I called a few oil and lube shops around... anything from Vavoline to Jiffy Lube. There's a Jiffy Lube down the street which would be handy. I used to use them prior to doing my own oil changes based on personal preference alone. When I called them the manager talked to me for quite a while. He said their service uses some sort of a machine which flushes out 99% of the transmission fluid and replaces it with whatever is recommended. No filter is changed, no pan is dropped, and it's 120 or 180 (conventional vs synthetic). He explained to me that when you drop the pan, you don't have access to the majority of the fluid, which normally resides in the torque converter. They use a process, something about turning the vehicle on yet having it in park and the torque converter spinning, along with a machine that is transferring fluid out and putting an equal amount of new fluid in. Both Vavoline and Jiffy Lube and a few small non-chain oil stops said they use the same process and all have the same prices -/+ 10 bucks or so. They all also said my vehicle is rated 50k to get it changed and that 54k isn't really pushing it badly but that I should consider getting it done relatively soon.

He also talked to me about the filter a bit, something about a magnet inside that does the job. I wasn't really understanding, but he said the filter isn't something that tends to get changed as often as an oil filter. He said if you had 200k on it and never replaced the filter, that's one thing. I then told him I'm at 54k and he said he wouldn't worry about it.

The other thing I am curious about is what I'm reading about transmission flushes. What is the general unbiased idea behind that? Is it true that a transmission that is in bad, bad shape would likely fail under a transmission flush? Whereas a transmission that has been flushed every 50k should operate absolutely fine?

What I'm grasping from what I've read is this (correct it if it is incorrect): Flushing a transmission does no damage to it, however if your transmission is having issues that you have not yet seen, flushing it may stir the waters and bring those issues to the surface much faster than it would have otherwise. Traditional flushing is done with solvents and detergents, which is where the above issue is. Flushing by most shops done today (including Jiffy Lube, Vavoline, and several other shops I called) said they use no cleaners or detergents but instead simply replace the fluid as the vehicle runs in park. I guess it's just a glorified drain/refill method since this process puts no pressure on the system and uses no cleaners, yet replaces 99% of the fluid. Hmm...

 

[C0RR0SIVE]

A magnet only grabs a bit of the metals, filters still trap the majority.

A flush is good on any transmission, AS LONG AS THE FILTER IS REPLACED, that filter will grab what is stirred up, hence the reason for a filter replacement after the flush.

A transmission on its last legs with a flush, after ignoring previous maintence will destroy it, fast.

 

[Jayce]

A magnet only grabs a bit of the metals, filters still trap the majority.

A flush is good on any transmission, AS LONG AS THE FILTER IS REPLACED, that filter will grab what is stirred up, hence the reason for a filter replacement after the flush.

A transmission on its last legs with a flush, after ignoring previous maintence will destroy it, fast.

I just find it interesting how a flush will harm a transmission. Then again, from what I've read the flush doesn't do actual damage to the transmission, it just uproots issues that would otherwise have surfaced down the road anyway.

The upsetting thing is to get a flush and filter replacement at the dealer is 250 bones when I just spent 270 on drivetrain maintenance last night. Yay, vehicle maintenance.

 

[C0RR0SIVE]

Yea, maintence will murder ya, but look at it this way, prevent it, and help it last longer, or shell out $2500 for a rebuild? That is the average in PA for clutch pack replacements.

BTW, the reason a flush will hurt a transmission if its ignored for too long, is because after awhile, the gunk in the transmission is what's holding it together, and the varnish on the clutch packs hardens then. When new fluid is introduced it eats that varnish off, and the clutch self destructs. Believe it or not, transmission fluid is some times used to do a slow "flush" of the engines oiling system due to the detergents in it.

 

[Jayce]

So for my own sake of understanding, if you flush a neglected transmission, the new fluid is what shocks the system into a cleaner/sterile environment which thereby causes issues.

I get that part. But what I don't get is the actual fluid. So if the old fluid is what's helping hold it together with what I would consider chewing gum and duct tape, how on earth can the old fluid just continue running? Would it not break down to the point of ultimate transmission failure?

I compare it to this, and maybe this is inaccurate, but here's what I'm comparing it to: My engine needs new oil every 3k miles or so. I waited till 5k. Oh crap, the oil cannot be changed, so just keep driving it indefinitely.

I just don't see how further neglect of the transmission fluid can somehow allow it to keep running.

Also, is it really the new fluid that breaks down the build up? I would think it would be the thorough solvent cleaning some flush systems do as opposed to the actual fluid itself... Hm??

About what I'm going to do: 250 is a bit steep for me right now to drop the pan and get a new filter as well as new fluid cycled through. Most shops I talked to today said the average person does a transmission cycle @ 50k, then a cycle + filter @ 100k. I wonder if that'd be an acceptable route for me to go?

 

[C0RR0SIVE]

I think that would be perfectly acceptable, as worn out fluid causes accelerated clutch wear. You should be ok as long as your not basically flooring your car often and drive like a normal human, but as with everything she will EVENTUALLY loose something, be it a clutch pack, or a planet carrier, or even the pump in your transmission, even a 24/7 supply of brand new fresh cool fluid wouldn't stop it.



There is one key difference between oil and transmission fluid, oil normally becomes thicker, while transmission fluid becomes thinner. BTW, when doing a flush, they just pump a whole lotta clean fluid through the system, the solvents are the detergents and that's why transmission fluid can last so long, because of how strong the stuff is.

Also, engine oil has exhaust deposits (you still get blow-by gasses in an engine no matter how many piston rings you have over time) that build up, among other acids that are harsh on the bearings. Strangely, bearings are weaker than your clutchs, as you can scratch a bearing with your finger, and the oil from your fingers alone can ruin them.