Changing Transmission Fluid

A drain and fill probably only gets 1/3-1/2 the total fluid. I don't know why a flush would be harmful so, I say go for it.

Has the front diff oil been changed? Can you describe the noise you're having? Someone may have experience with it. Although my wife's 03 H6 OBW auto has ALWAYS had a little front diff buzz, it has less than half the miles your does.

Nothing will ever be fixed by a flush, and there is lore that a high- mileage flush can cut shorter an already limited transmission lifespan.

A drain-fill is not so tough, do 3 within a short time period.

If you have a trans problem you can actually hear nothing you do is going to make much difference.

Dave

I worked for a dealer. We did a flush on two cars (albeit Ford Escorts...) and the trannies quit shortly after, one after about 200 miles, and the other....on the way back from being flushed...

Never did another flush. One of the cars only had 127,000 on it.

Yes, but had they been serviced in that time? I have also heard of these issues before, but associate them with ; A. older model years and B. cars with no interim tranny servicing. The OP said he did a drain/fill once. (maybe he should have done 2-3, I don't recall.)

Yeah, a couple more would have been more in order.

Fact is, I never did any AT service the few times I did have cars with ATs. I had a Honda Accord, and changed the oil every 3,000, but never did a tranny service. I don't know if th wife did; she would take the car to the dealer for 'regular' service, but the car went 220,000 miles...

The weather here helps kill tranny fluid so, 'careful' car owners will do dr/fl or flushes. But, as mentioned, I've known some folks, mostly domestic car owners, that just would not do it on older used cars they bought for fear it would CREATE a problem.

Happened to an Isuzu Trooper I had. Over 100k miles flush and fill and dead trans. Vehicle having a GM transmission may have been a big part of it though

Just had a drain/fill on my Hyundai Santa Fe at 60K and was a bit worried because the fluid looked dark to me after a week. Dealer looked at it and said it was OK. He said that they never flush trannys anymore as they cause more problems than they help, and a drain/fill doesn't get all the dirty fluid out, so the result will be darker than new, but not a problem.

Jon

Fresh fluid NEVER hurts an automatic. If it fails after a fluid change or flush using the CORRECT FLUID, it was going to fail anyways.(unless whoever changed the fluid did something else and screwed things up)

From my own experience; and from many other peoples 'opinions', not so. Mine's not a totally bad one, just irritating.

Unless it's been flushed from fairly early on; under higher mileage/use/conditions; the more likely there's going to be various cruds sitting in various nooks and crannies on the transmission housing.

'Cruds' could be sludge bodies, metal shavings, little unwanted parts left in at the factory....

Flushing drags them out of hiding. Depending on what popped it's head out, damned near anything can happen.

AFAIK; my oughty-ought Outback got it's first flush at 99K miles. I did it as "preventative maintenance" as I didn't know the whole service history when I bought it at same 98K. I wasn't having any problems with the trans before in the 3 months I had it.

And YES; it was the CORRECT fluid and done right. I know the shop that did it very well. They are about 2 blocks from where I work.. and there's a big customer base involved as they know the word gets around real quickly when they screw up. They've been in business for 50+ years.

They did a reflush for free. Still have

I'm fairly lucky; whatever came loose during the flush only causes "morning sickness" of not going into a forward gear (not reverse) when started cold. It's "liveable with". On this one, it's not the anti-drainback valve for the torque converter (reverse is OK..). I've tried various additives and found that SeaFoam Trans Additive works for ~2-4 months. It's a "solvent-type" mouse milk. I've tried the thick goo like Lucas trans additive, no luck.

BTW, same trans shop buys me the SeaFoam.

Manager (who's the present owner and came up from the ranks as a wrench-spinner there ) says there's about 1 out of 80 hi-mile trannies that have problems. Out of those, it all depends on the year/make/model of transmission what the results are. If it's traditionally a "grenaded" trans, they severely advise against it. Others are on a case-by case basis. Howard says this is the second Soobie 4EAT that's given post-flush problems since he started. The other was a "grenade" that had a clutch-band disintegrate.. shit happens.

In all reality, a flush problem is rare. How many of us here who've

*NOT* had a flush problem said so? This ain't Twitter, and I don't think many of us who use newsgroups are going to shout out to everyone when we had successful work done on a car problem that wasn't in a current discussion.

One "Aw Shit" trumps one thousand "AttaBoys".

I suppose then, a 'flush' is definitely to be avoided. However, multiple 'drain/fill' cycles (maybe 3 or so -?- as mentioned in another post) would replace the majority of the old fluid without the risk of dislodging particles.

Or does someone feel there is risk from the new fluid itself?

No. I'd say the average automatic transmission is just neglected.

People don't change auto transmission fluid as regularly as they should. Period. The 'severe service' interval for Subaru tranny fluid is 15,000 miles, as I recall from my Service booklet.

Who does that? Almost nobody.

High speed driving, mountain driving, towing, city 'stop and do' ...driving in hot or dusty climates (probably half of US territory qualifies), ...are all severe service.

On average the engine oil in the US gets changed fairly frequently if not too often, all together, but tranny fluid? This one can be let go for 60-80k miles or even more.

Then you're bound to see all sorts of problems, like the flush problem.

I change my tranny fluid at 15-20k miles, use 50/50 mixture synthetic ATF, and also have had tranny coolers installed in all my cars (when still new, less than 500 miles on odometer). No tranny problems in years of beating the crap out of auto transmissions during regular high speed hot weather mountain driving.

I am not advocating everybody do this, but a simple ATF change every 30k miles can go a long way!

Basia

Wow. That's cool.

I was selling used cars for a while, and we were selling S00bs for a guy who used to be a S00b tech, but now works on "toys" like Ferraris and Lambos at a high end "Previously owned" dealer about 50 miles away. WHenever we sold a car for him and the customer came back and said, "The tranny is doing..." he said, get some Sea Foam and throw some in. Usually did the trick.

Well, I've owned LOTS of automatics over the years, and have always maintained them - meaning proper fluid flush and filter changes. I seldom get rid of a vehicle with less than 240,000km on it, and have only had 4 transmission failures in 52 years. One was a blown torque converter/front pump seal on a 3 liter Aerostar, one was an accumulator seal on a 3 liter aerostar (external leak - fixed it on the driveway) and one was a complete failure on a 3.8 trans-sport at about 300,000km ( which I bought at 275,000 with no service history. The forth was a twisted of input quill, also on the 3.0 Aerostar (failures were spread over 2 vehicles and 480,000 km). In about 25 years as a mechanic I NEVER had a transmission failure that could remotely be blamed on a fluid change/flush done in my shop

- and we did a LOT of them as they were called for on the Toyota service schedule of the day. (about 12 years of the 25 were at Toyota dealerships)

Another "fix" that often works for morning sickness and other shifting problems is a dose of Ford "friction modifier" (for differentials) added to the tranny fluid. Stinks to high heaven - but it works.

Are you in Canada? You state milage in kilometers. Canada is much cooler than US and that can make a difference.

I think that in the US there is a "culture" (for lack of a more precise word) of neglecting auto transmissions. Engine oil gets changed here very frequently but not so tranny fluid. I think that's why all the flush problems.

Basia

That it does. The "Hachiroku" has an LSD and I had to add that stuff to it.

I'm in Canada - but it's been in the high 30s C for several weeks - That's Mid Nineties F - so "much cooler than the states" is somewhat subjective, and depends a LOT on where in Canada and where in the states. Both are VERY large and diverse countries.

In the US there is a "culture" of neglect - period. In Canada it is also getting that way. Everyone wants everything for as low a price as possible and expects it to last forever without upkeep.

I used to go to Toronto every year, and I never really found it much cooler than Massachusetts, temperature wise.

But, Toronto is a cool city!