Help with Tranny Fluid!

[Kevin in Texas]

I went last week to my regular Transmission shop and had my fluid and filter changed on my '93 Explorer with 105K. He has now switched from Pennzoil to Exxon Superflow ATF.

With the new fluid, it does not seem to shift as clean as the old Pennzoil ATF. I did some checking on the web and Exxon's ATF has a Visc at 100C at 6.9 versus Pennzoil's 7.3 and Valvoline's 7.7.

Since I don't know much about how transmissions work, what effect would a lower visc have on shifting performance? Is a higher visc better? Are there additives in Pennzoil's or others that allow better shifting?

The bottom line is that I don't want to go and spend $1000+ to have my transmission repaired and am contemplating draining changing my fluid out again myself and going back with either Pennzoil or Valvoline.

Opinion's and comments?

 

[Spector]

Before blaming the fluid check to see it was filled properly. No shop I know of takes the effort to properly check the level. They do not measure what comes out and in lieu of driving the vehicle 10 miles to heat the transmission up as the manual says they simply let it idle at best which does not do the job. they could easily underfill or overfill it so drive it 10-15 miles and check when hot with engine running. If level okay then explore other issues.

I no longer permit any shop to change my, they were screwing it up 75% of the time on the fluid level.

 

[Al]

quote:

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Originally posted by Spector:
Before blaming the fluid check to see it was filled properly. No shop I know of takes the effort to properly check the level. They do not measure what comes out and in lieu of driving the vehicle 10 miles to heat the transmission up as the manual says they simply let it idle at best which does not do the job. they could easily underfill or overfill it so drive it 10-15 miles and check when hot with engine running. If level okay then explore other issues.

I no longer permit any shop to change my, they were screwing it up 75% of the time on the fluid level.

---

Agree here. Check your manual on exactly how to do the check. Normally you must be up to operating temp. and sitting very level. Yoy slowly put the vehicle thru all of the gears while the car is idling. Then immediately check the level. One thing you could try is a product callled "Lubeguard" . Even reputable shops use this product to improve shifting. Its around 1--12 bucks at NAPA.

 

[jjbula]

Kevin,

I don't have an answer for you but have been struggling with the same type question.

The only ATF I can find here is Castrol , Quaker state, Quaker state Multi-vehicle, Aamco, and Mobil 1 Synthetic ATF.

My thoughts were along the lines of synthetic or not synthetic.

The Mobil 1 Synthetic ATF has a higher VI and 220C flashpoint. Most other fluids have 190 to 200C flashpoint. I have heard people complain, though, that it doesn't provide enough friction for some trans to operate properly/smoothly.

 

[jjbula]

quote:

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Originally posted by Kevin in Texas:
I went last week to my regular Transmission shop and had my fluid and filter changed on my '93 Explorer with 105K. He has now switched from Pennzoil to Exxon Superflow ATF.

---

Another tidbit that doesn't answer the question.

A Ford dealer told me that Ford recommends the Mercon V for my 95 Windstar. The factory fill and manual called for Mercon. My understanding is Mercon V is a synthetic blend (group III??) and is better in cold temps.

I don't think you will a problem if you change every 20K. My transmission guy says the transmission fluid additives wear out quickly, especially in the Windstar.

 

[Kevin in Texas]

quote:

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Originally posted by Spector:
Before blaming the fluid check to see it was filled properly. No shop I know of takes the effort to properly check the level. They do not measure what comes out and in lieu of driving the vehicle 10 miles to heat the transmission up as the manual says they simply let it idle at best which does not do the job. they could easily underfill or overfill it so drive it 10-15 miles and check when hot with engine running. If level okay then explore other issues.

I no longer permit any shop to change my, they were screwing it up 75% of the time on the fluid level.

---

I did check it hot per the owners manual and it was overfilled by about an inch past the full mark. But I did not think much about being overfilled.

How does being overfilled affect the transmission?

 

[jjbula]

That is definitely a possibility in the future.

Just changed the fluid in my Camry and Windstar this month.

 

[MolaKule]

Overfilling can cause aeration which puts air bubles into the oil, reducing the oil's ability to provide film and making the oil "compressible" instead of incompressible, which would interfere with the operation of hydraulic pistons and valves.

They probably filled it cold, and when the transmission became hot, the oil expanded. I had that happen not too long ago after having a quick lube replace the pan gasket and filter. The new guy learned a lesson in "fluid volume" thermal expansion after I made him remove a 1.5 L.

If it is really overfilled, I would expect to see bubbles on the dipstick about 10 seconds after shutdown.

 

[lee]

I'm a newbie here so forgive me if I step in where I shouldn't, but...

The first post asked about vis at 100C. A Subaru tech bulletin (couple of years ago) suggests comparing the vis at -40C. The lower the number suggesting a better base stock or more expensive refinement. I realize this was on a Ford, but I think the original Dexron II spec was 40K, Dexron III at 20K, and M1, Amsoil, and Royal Purple all around 6K (from memory without reviewing their specs).

From this I would infer the lower number to be better, but not sure how it extrapolates to the 100C value quoted.

 

[dragboat]

jjbula's post raises a question for me,I wonder where Castrol and Aamco gets their base stock from?

About a month ago I pulled my Mothers car in the shop to service the trans,got the pan off and went to get some MerconV and a filter,that Mercon V was not so easy to find! Wound up having to put Aamco in it,it was all that was available here in town
I wish all cars had a drain on the torque converter to get a more complete change

 

[Kevin in Texas]

quote:

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Originally posted by dragboat:
jjbula's post raises a question for me,I wonder where Castrol and Aamco gets their base stock from?

About a month ago I pulled my Mothers car in the shop to service the trans,got the pan off and went to get some MerconV and a filter,that Mercon V was not so easy to find! Wound up having to put Aamco in it,it was all that was available here in town
I wish all cars had a drain on the torque converter to get a more complete change

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Exxon makes Aamco ATF. If you go to Exxon's website you can get to the ATF and it has Aamco logo's on it.

 

[jjbula]

quote:

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Originally posted by Kevin in Texas:
Exxon makes Aamco ATF. If you go to Exxon's website you can get to the ATF and it has Aamco logo's on it.

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From Exxon Mobil about Aamco Mercon V fluid--

Viscosity
cSt at 100°C 7.5

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cP @ -40°C (40°F) 10,500

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Flash Point, °C (°F) 206 (403)

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Pour point, °C (°F) -55 (-67)

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Gravity, °API 34.1

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Color Red