ATF Fluid Change Not Recommended?

[Ruminator]

Hi everyone, I'm glad to find and become a member at your great site.
I'm using my first post to ask for some help in understanding the pros/cons to changing ATF fluid in a trans. after it acquires mileage above 60,000 miles.
My friend has said not to do it because any new fluid will have all good additives, etc. and overly slippery properties due to the well worn surfaces on everything.
Is this a generally agreed upon fact? I just purchased a used Ford Ranger with 87,000 miles on it and was going to change to Amsoil or Schaeffer's, etc. along with an oil change.
Thanks guys, I'm learning tons more than I have known about my cars due to you.

 

[Ruminator]

Not sure how to edit my above post to include - is there also a mileage limit to changing the rear end lube?

Thanks.

 

[Ruminator]

He also said that with the old fluid having lost alot of its detergent cleaning capabilities there are built up coatings (shellac-like) that new fluid would remove and change important gaps and tolerances?

 

[Colt45ws]

Myth. Change the trans and rear end out.

 

[Donald]

So do we assume its never been changed before, or has, been but now total mileage is 60K. I agree that its a myth with respect to changing the ATF and read end fluid. For the AT, you need to drop the pan and clean it and replace the filter, then fill with fresh fluid. Depending upon how bad the old fluid was, you should drain and refill a few times so almost all of the old fluid is replaced. Look on the Amsoil web site under ATF fluid and they have a 14 step procedure you might want to follow. They also make excellent ATF.

 

[Whitewolf]

I don't think you told us what vehicle and MY we are talking about. That would make a difference.

 

[wantin150]

Draining and re-fill is better than leaving old fluid in there. A flush is usually not recommended in higher mileage transmissions.

Rear diff fluid should be changed, IMHO, at that mileage. Shouldn't see any issues with that at all.

 

[adam123]

Ford recommends a change interval of 100K in their rear diff's any way, at least if they haven't changed their recommendations.

 

[XPR]

Quote:

---

Draining and re-fill is better than leaving old fluid in there. A flush is usually not recommended in higher mileage transmissions.

Rear diff fluid should be changed, IMHO, at that mileage. Shouldn't see any issues with that at all.

---

Didn't have any issues when I had my trans flushed with 110k on it. I think that a flush causing damage is just another myth.

 

[Ruminator]

Sorry guys, the Ford Ranger is a 1991, 2.3 4 cyl. engine, auto/overdrive tranny, with 87,000 miles on it.

 

[Ruminator]

Donald- yes, I guess we need to assume that since there are no maintenance records that came with the truck and I didn't buy it from the original owner.

Its actual mileage is 87,000 miles. My friend was saying that vehicles over 60,000 miles shouldn't get an ATF change if they've never had one prior?
.

 

[Tempest]

If you are really worried about it get some Auto RX and do a run with it on the trans before flushing it out. This will safely and slowly remove and junk. Then do a full flush with a quality Mercon V rated product. Oxidized fluid full of wear metals is not good for your trans, get new stuff in there.

 

[Ruminator]

Quote:

---

If you are really worried about it get some Auto RX and do a run with it on the trans before flushing it out. This will safely and slowly remove and junk. Then do a full flush with a quality Mercon V rated product. Oxidized fluid full of wear metals is not good for your trans, get new stuff in there.

---

I plan to use AutoRX after changing the oil and running through this tank of gas in which I've added a full 15 oz. treatment of Redline SI1.
After which I will use Schaeffer's in full synthetic for maintenance purposes.

Adding some RX to the tranny sounds good also before changing it, how much are guys adding to them?

Noone has posted about issues from changing out the possible OEM ATF?
.

 

[dave1251]

Mercon V is not the OEM fill for your Ford. Mercon III was if I am correct. But Mercon V is so much better. You should not have any issues changing to Schaffers, Mobil One, Amsoil. Or even Dexron.

 

[The Critic]

Mercon V supercedes Mercon. No Mercon III fluid ever existed.

 

[mechtech2]

Tell your friend the new friction modifiers may well cause it to grab more, not slip more.
Mercon V was not recommended by Ford to use in Mercon systems for years, but now is fine and dandy with them!

 

[Big Jim]

Quote:

---

Tell your friend the new friction modifiers may well cause it to grab more, not slip more.
Mercon V was not recommended by Ford to use in Mercon systems for years, but now is fine and dandy with them!

---

Friction modifier does indeed cause the lubricant to be slipperier. That is why it is added to clutch type limited slip differentials, to keep the clutch plates from chattering on turns.

 

[artificialist]

Do your ATF change, and do your rear axle oil change. I have seen far too many trucks where the rear axle oil is ignored, and at 100,000-120,000 miles, a bearing fails, damaging the axle shaft, causing a repair bill that is between $300 and $600.

Also, if your Ford has 4WD, go ahead and do the front gear oil change. It is cheap protection.

 

[Donald]

I would drop the AT pan before I did anything with the AT. Even before you add Auto-Rx. You need to see the condition of the fluid (red or dark red or black) and how much crud is on the bottom of the pan or filter or magnets. For example you would not want Auto-Rx or new ATF to loosen up anything at the bottom of the pan when you can wipe that off.

 

[doitmyself]

If you plan to keep your vehicle for a long time, you have to consider the two alternatives.

Even IF you believed your friend's advice (myth).....over the next 50K miles the fluids would breakdown even more and expensive repairs would almost be guaranteed.

Drop the pan/filter and determine the "gunk" factor. Then either 1.)Auto RX it to remove deposits and condition seals or 2.)change over the fluid - maybe do a partial change first time to slowly introduce new detergents, then do another change after 6 months??? Just an idea.

I think the worse of two evils is to leave the old fluid in. I think your myth started due to people NEVER maintaining their fluid to the point that damage occurred already. Then they change the fluid, the tranny breaks....not because of the fluid , but because of previous damage/coincidence.

Some people have the same thing occur with coolants.