Transmission life. How to get the best?

[mechtech]

Put a supplemental oil cooler inline with the stock one in the radiator. If it has an external one also from the factory, get a bigger one.
Change your fluid every couple of years, or 30,000 miles or so.
An inline filter is a good option - they look like fuel filters.
A synthetic ATF wouldn't shear like a dino, and is better overall.
Happy motoring!

 

[Dan4510]

Use the biggest trans cooler you can get to fit. Put it after the stock cooler. Every 20 degrees drop increases life of fluid by a large amount. Use synthetic fluid. Use an inline filter and drive easy.

Hard shifts chew up clutches, steels, and bands. Not only that puts a lot of strain on motor mounts, trans mounts, and u joints.

Dan

 

[Iain]

quote:

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A synthetic ATF wouldn't shear like a dino, and is better overall.

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Additionally, synthetic ATF are much more tolerant of high and low temperature variations.

This alone may solve the problem of external cooling for those who don't have the space or desire to add them for whatever reason.

 

[Ramblin Fever]

I think the biggest factor, aside from fluid changes, is how one drives. I do think quality built has a lot to do with it as well, but let's face it, there are a LOT of drivers who are just flat ROUGH on their vehicles.

FWIW - I'm switching my new '06 Xterra auto to synthetic transmission fluid, may end up waiting til warranty's up though. Not sure on that yet.

 

[bulwnkl]

Though it pains me terribly to say it, I know from hard experience with automatic transmissions in well-worked 4x4 farm pickups in the '80s, '90s, and '00s that frequent fluid changes don't do much at all for longevity. We normally changed ATF, filter, & adjusted bands in our pickups either at ~50,000 miles or else never. Then, we started changing it every 24-30k miles (depending upon which pickup and what the book said). The increase in transmission life was somewhere between margin of error and 10% (which is most likely still well within build margins). They lasted ~100,000 miles and then they needed a rebuild. They weren't sludged, they weren't clogged, they weren't overheated; they were simply worn out (talking about wear parts here, not necessarily gears/bearings). I really, really wanted it to not be so, but it was.

I still change A/T fluid at least once in a vehicle's lifetime, but experience has shown me that a working automatic transmission lasts as long as it lasts and that's it; it's not dependent upon frequent fluid changes. If you are definitely overheating the fluid, you probably should add a cooler. We weren't, so the factory coolers were clearly enough for us.

 

[ULVER]

*Practice a little TLC with your driving...

*Install the largest cooler available--my Police Interceptor came with one. I replaced it for one rated for a Mobile home, towing a small car

Even my lowly Ford Escort has one now!

*Use a synthetic ATF...

*Go 30K max w/synthetic or 15K with conventional (overkill

? With trannys, I like it!)

*Apply a bottle of LubeGuard apps to your vehicle & fluid-- one of the few additives that's not snake oil!

*Replace the filter! Many of the "exchange services" claim this is not needed.

Supply a OME filter, and pay more to have the old one changed. If they scoff-- leave! It's not called a "filter" for nothin'...

 

[Ramblin Fever]

quote:

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Originally posted by bulwnkl:
Though it pains me terribly to say it, I know from hard experience with automatic transmissions in well-worked 4x4 farm pickups in the '80s, '90s, and '00s that frequent fluid changes don't do much at all for longevity.

I still change A/T fluid at least once in a vehicle's lifetime, but experience has shown me that a working automatic transmission lasts as long as it lasts and that's it; it's not dependent upon frequent fluid changes.

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Truth of it is, automatic transmissions of the 80's & 90's in and of the big 3 were not all that good to begin with. Where I come from, most farm/ranch trucks were stick shifts for that very reason.

Still debating whether they have improved any, in the full-size truck department. They seem to be fine for an everyday vehicle, but when you add a load - i.e. trailer, camper, etc. light-weight or heavy, they seem to crash by around 100k miles or so and ALL of the big 3 are guilty of this trend.

If the assumption really is in the fact that all the fluid changes really will not increase life, (obviously it won't help a defective tranny from the start) I'm amazed at how many still do it anyway.

I understand clean fluids give peace of mind, but if the belief (or proof) lends to the fact that it does not increase overall life of a transmission then why bother spending the time, or shelling out the money on fluid changes?

That's just a general question - BTW.

For me, I'm still going to continue as I have, as I have a truck with a GM tranny that's already surpassed (with a hard-working life) what some people believed it wouldn't.

My belief is without the constant attention to fresh fluid every 25-30k or so, it wouldn't have lasted this long with as good of shift quality.

My Dodge is the one that concerns me, with their automatic history, I refuse to drive it in a lot of stop/go traffic for this very reason - it gets new fluid every 15k miles without fail. And, when it does hit the road, it is with a camper and trailer - so we'll see how long it lasts.

 

[b_rubenstein]

There are lots of "soft" (seals and plastic parts) parts in a transmission that don't do so well when exposed to high heat for long periods of time. Most of the heat in a transmission comes from the torque conveter when it isn't locked. They generally don't lock up below 50 MPH. Driving around on a farm with a loaded truck or pulling a trailer will drive the fluid temperture very high. Even with a great synthetic ATF that can handle the heat, other parts will be damaged with time. Along with fresh fluid the best thing for an auto trans is an auxiliary transmission cooler. Assuming no inherent design defect, or parts, with fluid that stays below 200º F and is fresh, the trans will last a long time.

 

[JHZR2]

quote:

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Originally posted by The Critic:
Three ways:

1) Drive Gently

2) Avoid towing whenever possible

3) Change the ATF at the OEM recommended interval for severe service, using an approved fluid or upgraded synthetic fluid.

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Driving gently is the #1 most important thing, IMO. My father's 94 previa has the original transmission that shifts like new at 200k. My mother's 97 plymouth breeze has just under 100k now of mostly 5 block commutes. Talk about lots of shifts, which does wear stuff down. Granted there isnt a lot of heat when that is going on.

But gentle driving never seemed to hurt anything.

JMH

 

[Leo]

Nice input guys. So whats usually the cause of transmission failure (due to wear and not faulty parts)? Worn clutch packs? Anything that synthetic fluids can prolong?

 

[bulwnkl]

Synthetic fluids will not prolong the life of wear parts like clutch packs if they're designed to the same specs as the factory fluid. This only makes sense; The frictional characteristics of the fluid in the clutch packs during lock/unlock have to be what they have to be in order to provide proper action. Thus, those wear parts' lives won't be increased. During my farm maintenance program calls to several oil companies and extensive conversations with them all, they all told me (some had to be pressed) that the life of parts like clutch packs will not (and should not) be increased with a synthetic fluid.

IMO, synthetic ATF could be good for increasing the fluid's life under high-temp conditions and perhaps for extending gear and bearing life if well designed.

 

[unDummy]

Concerning synthetics:
There is more to clutch wear than what is mentioned.
Sorry, but there are too many other indirect benefits to a synthetic ATF when considering clutch or band wear.

I've increased clutch life with synthetics. Don't know why stupid oil companies can't. Maybe you should've called the transmission companies, clutch/band suppliers, or rebuilders and asked them for an opinion.

Synthetic fluid flows better and lubricates better. When cold, some transmissions shift poorly(slow). A synthetic can help and in turn reduce wear.

When overly hot, a transmission relies on the fluid to remove the heat. Which works better, a fluid that can take the heat, or one that is beginning to boil into varnish or sludge?

Valve bodies can wear out, or varnish up. Prevent that with a synthetic. This means that the clutch packs or bands are applied correctly. Nothing like blowing out a clutch pack because of a slow binding piston, solenoid, or excessive ATF PSI leakage, which all would cause excessive slippage during the shift or slippage when power is applied after a completed shift.

Which is better for cushioning those clutch faces, steels, or bands during a shift? A synthetic ATF that can maintain ~7 CST viscosity over its entire life or a mineral oil that quickly shears to 6 CST or less. The same could be said concerning all other lubricated components. Anyone want to guess whether sheared ATF is a better hydrodynamic barrier lube when compared to an ATF that maintains its viscosity?

I've also experienced thermal runaway in certain overworked transmissions. This would destroy clutch material and actually weld the steels and clutches together relatively quickly. Simply switching to the synthetic prevents the problems and extended the life easily by 5 times.

And, if synthetics didn't improve transmissions life, then why aren't we all still using a straight mineral oil? EVERY automaker is using synthetics or blends in most of their vehicles.

Concerning ATF change intervals:
More frequent is better.
Increase life by removing any wear that is accumulating in the fluid. OEM ATF filtration is pretty pathetic.
Reduce wear by keeping the viscosity where it needs to be for proper transmission function and protection.

Like I've said before, LEARN YOUR TRANSMISSION. Mod for the weaknesses. Some need better cooling. Most will benefit from a synthetic. Some might benefit from additional filtration. Other might need mechanical improvements like simple VB mods or shift kits.

Mine get everything and last forever.

If you have a tranny that dies at 100k miles because it just wore out, and improved fluid, cooling, filtration didn't help, get a new rebuilder who can address the known weaknesses.

 

[Ken2]

1) Don't shift into the other direction while you're still rolling. Duh. That could be what killed those farm truck transmissions especially if the trucks were loaded heavy and an employee was driving.

2) Keep the fluid clean. An inline filter (Magnefine, SPX Filtran, WIX) works well.

3) Keep the fluid in good condition. Some componets of the fluid do wear, thus the shudder in some transmissions. If you get the shudder, flush & renew.

4) Send a sample of the fluid to a testing lab...A $20 test is better than a too-soon $150 flush.

5) Use synthetic PAO ATF if available for your transmission.

6) Keep the fluid normally warm, not hot. If running heavy, install an additional cooler.

7) Clean the transmission with Auto-Rx before each flush.


Ken

 

[1sttruck]

Drive autos a bit easier, don't tow, and change fluid often. We have a bit over 200k on a Taurus, it still drives fine when warmed up, but I somehow feel like I'm on borrowed time regarding the tranny.

Get a stick :^) A friend with a 1 ton diesel pickup said that he'd get a stick like mine the next time, as his auto will sometimes spend a fair amount of time trying to lock up. Chatting while waiting for a meeting to start a couple of Ford truck owners said they'd get a stick next time too.

 

[stingray427]

Again I understand it really isn't which brand you put in but the frequency of the changes/intervals.
So this means the engine oil has a tough life so breaking that in at 1,000 and doing the first change to get rid of shavings is what you want to do here. But this doesn't apply to automatic transmissions or rear end differentials.

 

[stingray427]

 

[The Critic]

To each his own, but while I respect unDummy's view, his recommendations are better suited for 1990 than 2006.

The new Dexron-VI/Mercon SP low viscosity fluids will remain at 5.5-6 cst (6 cst starting viscosity) even after 20,000 miles or more.

Synthetic oils preventing valve body wear is something that I just do not agree with. Many valve body issues that I know of are caused by poor design and are unrelated to fluid choice. The valve bodies would just wear out due to construction and an aftermarket fix was the only cure, not synthetic fluid.

Many OTC fluids are now synthetic blends. Seems like you believe that most OTC ATFs are from 1990.

Anyways, drive gently, add a cooler if you do not have one, drain the pan and add new fluid every 20-30K, and do a filter change around 100K, and you would've done the best you can.

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My mother's 97 plymouth breeze has just under 100k now of mostly 5 block commutes.

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Wow! 100K on a Chrysler 41TE/A604 unit?

 

[Steelhead]

heat is the killer of auto trannys...over 225d F ATF temp and the ATF is oxidized with significant changes to viscosity and additives
once the ATF fails, the special Torrington roller thrust bearings fail, bronze thrust bushings turn to fools gold in the pan, seals turn to rock hard hockey pucks and friction bands/plates turn to hard glazed garbage

 

[carock]

According to Ford's studies with the SAE, the lifespan of an automatic transmission in "normal" use can be doubled by preventing overheating and providing excellent filtration. They do this with a NZT filter and a good cooler on their heavy duty truck and some towing packages. In general, if you live south of Interstate 10, you NEED a supplemental oil cooler for your transmission. A good bypass filter will work wonders for transmission life according to several studies. Automatic transmissions cannot get oil that is too clean. Your transmission will also shift better because the valves will not leak and the clutches will last longer.It will also reduce your need for fluid changes.Synthetic ATF fluid will resist burning much better than dino fluid, which simply has to help clutch life.In the German cars I am used to working with, synthetic ATF was a necessity in California weather if you wanted to get more than 100,000 miles w/o something going wrong.

 

[JHZR2]

quote:

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Originally posted by The Critic:

quote:

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My mother's 97 plymouth breeze has just under 100k now of mostly 5 block commutes.

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Wow! 100K on a Chrysler 41TE/A604 unit?

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whatever the 4-speed AT is in a 97 breeze with the 2.0L engine... no signs of any issues.

JMH