Will old transmission fluid affect shift quality?

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The transmission fluid in the Buick is a light brown color, not red at all, but not dark brown or black either. I plan on having the pan dropped and having the filter changed. I know this will not change all of the fluid but will it be enough to "help" the transmission shift any smoother, or last any longer? As of now it shifts fine when cold, but when it warms up the shifts become firmer and clunkier. Not whiplash hard, just clunkier and firmer. Should a pan drop help shifting right away? Or should I wait and just have the whole thing flushed?
 
Originally Posted By: gregk24
The transmission fluid in the Buick is a light brown color, not red at all, but not dark brown or black either. I plan on having the pan dropped and having the filter changed. I know this will not change all of the fluid but will it be enough to "help" the transmission shift any smoother, or last any longer?


Always works for me, but my experience is only with 96-00 and 05-06 Honda Civic automatic transmissions and Toyota automatic transmissions.

On the Hondas I do 3x D & R recommended by Honda whenever the fluid is brownish like you mention.

The Toyotas I do pan drop with filter change and new fluid refill just once, and it shifts smoother then before and I have never had any issues with them.

No reason to flush if it already shifts fine, just change the filter & fluid once then do every 30-60k depending on the fluid you use.
 
A friend of mine noticed shift improvement going from 12 qts of '9 year old' Dexron III to 4 qts Maxlife and 8 qts of '9 year old' Dexron III, so in her case, yes.

This is for an Aisin transmission
 
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The Pan drop & filter change will most likely put enough fresh fluid in it to make a difference, Probably still has the original Dexron II/IIE in it & friction modifiers are depleted.
 
Dropping the pan and changing the filter might buy you some time on this 24 year old vehicle. SuperTech Dex VI or equivalent will outlast the vehicle.
 
147_Grain said:
Dropping the pan and changing the filter might buy you some time on this 24 year old vehicle. SuperTech Dex VI or equivalent will outlast the vehicle. [/quote

+1. Pan drop is the way to go.
 
Originally Posted By: clinebarger
The Pan drop & filter change will most likely put enough fresh fluid in it to make a difference, Probably still has the original Dexron II/IIE in it & friction modifiers are depleted.


A pan drop, filter change and refill of 7 quarts of DexVI will help. Take a look at the bottom of the pan and see how much residue is sitting there. That should help you decide how much longer another drain and fill is in order.

If that transmission fluid looks light brown coming off the stick, 7 quarts of outbound is going to look ugly in the recycle container compared to fresh Dex VI.

I've been conducting pan drop and filter on my Buick since new about every 25k-30k. My last process and look at residue has convinced me to not do a filter and pan drop anymore and use the Mityvac 7201 to pull it out the fill tube, measure and replace with fresh. The 4T65E has never given me a hint of issue with my maintenance nor foot stuck in the supercharger.

There is a good collection of 3800 owners and maintainers here. Listen up.
 
You bet you'll find a difference. I rescued the 4t60 in my BIL's 92 Ciera with a fluid and filter change. (It was not electronic though some think so-- had a vacuum modulator.)

I also added some stop leak goo, looked like cherry grenadine. Figured a little thicker would help the seals.
 
I'd go with MaxLife for the 4T60 as well. Having owned and maintained a half dozen GM full size cars powered by the 3800/4T6X powertrain, more with that exact transmission than not, I can tell you that transmission fluid maintenance is one of the most key aspects to both transmission longevity and smooth performance.

With several of my GM Hydramatics, I had great luck with using Seafoam Trans Tune before changing the fluid. I used it to restore some really awful shift quality with my '89 Bonneville, which continued to shift well for the 30,000 miles I drove it (until 152k)

In addition to fluid maintenance, you may want to adjust your shift pressure vacuum modulator (you'll see it sticking out of the transmission, directly down from where the airbox/intake tube is). A quick Google search will give you the low-down on how to adjust.
 
I personally have had much better success with tranny flushes and total fluid replacement. Theoretically it cleanses the entire system to prevent the detergent in the new fluid from breaking up deposits which can cause trouble. I did the pan drop thing twice an both times the trannys failed shortly after. Flushes I had problems and so far the 4 times I have done them they have performed flawlessly afterwards.
 
Drop the pan, replace filter, fill with maxlife or dex vi to the correct level. Then drive it until you sell it or it gives up the ghost. Doing a drain and fill every 30k miles after the pan drop is optional
 
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Originally Posted By: eljefino
You bet you'll find a difference. I rescued the 4t60 in my BIL's 92 Ciera with a fluid and filter change. (It was not electronic though some think so-- had a vacuum modulator.)

I also added some stop leak goo, looked like cherry grenadine. Figured a little thicker would help the seals.


Early 4T60E's also used a Vacuum Modulator, To control overall Line Pressure, 440-T4/4T60 units used it to modulate Line Pressure during downshifts only, A Throttle Valve is used during upshifts to control Line Pressure. To tell a 4T60E from a 440-T4 is easy....The 440-T4 has a Throttle Valve cable The 4T60E does not.
Later 4T60E's use a EPC solenoid (Electronic Pressure Control) to control line pressure.

4T60/440-T4....Vacuum Modulator, TV Cable, ECM controlled TCC Solenoid.

Early 4T60E....Vacuum Modulator, PCM controlled Shift Solenoids, TCC solenoid, & TCC PWM solenoid.

Late 4T60E/4T65E....PCM controlled Shift Solenoids, TCC Solenoid, TCC PWM solenoid, & EPC solenoid
 
Had a broken vacuum line on my '94, though the trans was on its way out. Replaced the cracked check valve and the trans shifted fine after. Something to keep in mind.
 
Since the fluid isn't red, I would do a drain and fill first. Then after a week or two of driving, I would then drop the pan and change the filter. Then you'll have more of the old stuff changed. Just my 2 cents.

Regards, JC.
 
Originally Posted By: JC1
Since the fluid isn't red, I would do a drain and fill first. Then after a week or two of driving, I would then drop the pan and change the filter. Then you'll have more of the old stuff changed. Just my 2 cents.

Regards, JC.


If there was a drain plug, I would gladly do that.
 
If you don't want to do a flush, then I agree with JC1. Do two drain/fills in sequence. If you don't have an at cooler in that vehicle (I don't know but seriously doubt it), that's easier than an at-home flush. I also agree with SPK20a00, getting all new fluid in is the best solution in the long run.

I really don't like leaving old fluid in an AT that's been there a long time. It's sheared, dispersants all used, etc. Why leave it in?

I also really like MaxLife ATF, great price in gallon jugs at Walmart. Mag1 is also a quality synthetic ATF and comes in two viscosity choices, delivered cheap via Amazon Prime. I have several high mileage vehicles using both and all are doing fantastic - including one with a GM 4L30E - a more finicky unit that yours from what I understand of each - and it works like new.
 
Originally Posted By: gregk24
Originally Posted By: JC1
Since the fluid isn't red, I would do a drain and fill first. Then after a week or two of driving, I would then drop the pan and change the filter. Then you'll have more of the old stuff changed. Just my 2 cents.

Regards, JC.


If there was a drain plug, I would gladly do that.


Go to Harbor Freight and pick up their cheap transfer pump and pump out as much as you can get from the fill tube. Then you can pull the pan without getting a shower of ATF all over yourself, and change out that filter. You will see marked improvements.

I'm still on the fence about upgrading to Dex VI versus a generic Dex/Merc fluid. GM says they are compatible, but that fluid in you trans right now is probably sheared down past the 100C viscosity of Dex VI, and the low viscosity is part of the banging shift problem. The trans cannot generate enough line pressure with the thin fluid to keep the clutch plates from slipping. You're far better off using a higher starting viscosity fluid that shears faster than Dex VI and just changing it more often than you would need to with Dex VI. JMHO.
 
Originally Posted By: threeputtpar
Originally Posted By: gregk24
Originally Posted By: JC1
Since the fluid isn't red, I would do a drain and fill first. Then after a week or two of driving, I would then drop the pan and change the filter. Then you'll have more of the old stuff changed. Just my 2 cents.

Regards, JC.


If there was a drain plug, I would gladly do that.


Go to Harbor Freight and pick up their cheap transfer pump and pump out as much as you can get from the fill tube. Then you can pull the pan without getting a shower of ATF all over yourself, and change out that filter. You will see marked improvements.

I'm still on the fence about upgrading to Dex VI versus a generic Dex/Merc fluid. GM says they are compatible, but that fluid in you trans right now is probably sheared down past the 100C viscosity of Dex VI, and the low viscosity is part of the banging shift problem. The trans cannot generate enough line pressure with the thin fluid to keep the clutch plates from slipping. You're far better off using a higher starting viscosity fluid that shears faster than Dex VI and just changing it more often than you would need to with Dex VI. JMHO.


Well, I had my local shop do the work today. They gave me a fair price for the pan drop + filter, and the coolant flush. So the trans filter was changed along with 6 quarts of fluid. This was enough to turn the fluid from light brown, to light red. The fluid now smells like transmission fluid, it has that sweet smell. But now since the filter is changed, and is good for another 50K or so, I am thinking about getting a pump and doing some "pump and fills" with Maxlife to change out even more of that old fluid.
 
Originally Posted By: gregk24
Originally Posted By: JC1
Since the fluid isn't red, I would do a drain and fill first. Then after a week or two of driving, I would then drop the pan and change the filter. Then you'll have more of the old stuff changed. Just my 2 cents.

Regards, JC.


If there was a drain plug, I would gladly do that.


You can pump it out via the filler tube with one of these - works like a charm.

http://www.harborfreight.com/multi-use-transfer-pump-66418.html

BTW - I'm surprised no one has mentioned "Lubegard."
 
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