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High mileage transmission, change fluid or not?

It looks like this is gonna be a war between everyone pre 04 usin dexIII and everyone post 04 ^ usin dex IV...
 


Yay internet.

Dex 3 is the only fluid I'd ever use in a 97-03 car. Or any other older car for that matter. Everyone on the performance truck board that I'm on uses dexron 3 in all the older 4L60e and 4L80e's because the fluid in non synthetic and works better for those older transmissions. Some even use tractor fluid because all the transmission is is a hydraulic pump and that fluid will hold up far better to wear/heat.

I'd save myself a few bucks too using the cheaper dexron. I'd even use the regular merc/dex fluid because that would work just as good and is still cheaper than newer dexron.
 
FordMan77 said:
Take and wipe the trans dipstick on a clean white towel and see what color it is. Also see what it smells like. If it smells burnt and has a brown/black color on the towel then you may just be looking for a used trans at this point. That's a lot of miles on that old fluid so it's probably not helping things and I'd bet the filter is clogged up by now. The issue at 80K sounds like they may have upped the line pressure to get around the P1181 max adapt shift code (the slamming into gears thing).

If it were mine, I'd drop the pan and install the shift kit, change the filter and refill it with a bottle of Lucas + Dex 3 to top it up and see what you get, but would also be looking for a used trans in good shape as a backup. These things aren't known to be strong in stock form and with that amount of mileage it's a roll of the dice at this point. Just my .02
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I have already removed the dipstick to check the color of the old fluid, it is light brown in color, not dark brown or black. And there is no burnt smell at all.
A local GM mechanic, who has also done extensive work with GM transmissions, was able to confirm that the fluid does not have the burnt odor, which he said is a sign that the transmission is toast. The brownish color is not good, according to him, but it is the original factory Dexron 3 fluid, so he says to expect that. He said, from experience, that cars driven in the city in constant stop/go traffic, and idling for long periods (especially in hot weather) have the most early transmission failures due to the fluid breaking down. He said if mine is still shifting properly at 241,000 miles, that I must do a lot of open highway driving. I can approximate that 40% of my driving is at speeds of 25-55 mph, and about 50% is at speeds 55mph and higher. My 40th Anniv. spends very little time in heavy city traffic. Also, I drive in mostly flat terrain, and I have never towed a trailer, camper, boat, etc.
He also said that one bad thing is that the filter is, by now, all saturated with dirt, clutch material, and stuff.
He strongly advised against any type of flushing, as that would cause more problems than it will solve. So, he advised to drop the pan, install new filter, Dexron 3 fluid, and perhaps 1 bottle of a transmission additive. Then drive it for a few thousand miles. Then drop the pan, and install another new filter, and new fluid and a transmission fluid additive.
 
Mike Kerr said:
Please take a second look before putting any DEX III in your car. DEX III is no longer licensed by GM. DEX III no longer has to meet any quality or content or formula standards. I can legally take used motor oil, dye it red, and put in in a bottle and sell it as DEX III.

Put DEX VI in your car. Has major improvements over DEX III, and is licensed by GM to exact standards. Wal-Mart has a great price on DEX VI.
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I would like to upgrade to the Dexron VI, but in other threads, it has been questioned if it is possible to remove all the old Dexron III fluid before adding Dexron VI. I thought the 2 are not compatible. Also, in order to remove 100% of the old fluid, doesn't the transmission need to be disassembled?
 
They work just fine with each other, there is no problem mixing them together.

It's the same with synthetic motor oil, you can dump whatever the heck you want into the engine on some. You can mix both without caring.
 
Fivefingerdeathpunch said:
They work just fine with each other, there is no problem mixing them together.

It's the same with synthetic motor oil, you can dump whatever the heck you want into the engine on some. You can mix both without caring.
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Ok. I have heard that in an old 4T65E with Dexron III, if one drops the pan, replaces the filter, and changes to Dexron VI, there is no great harm.
My issue right now is dealing with the fact that I have 241,000 miles on original Dexron III from the factory, and original trans filter. I don't want to have the transmission flushed (which is good advice) but I don't want to drop the pan, and add Dexron VI with any percentage of old Dexron III in the transmission. That's why a local mechanic advised draining as much as I can and adding Dexron III, with a new filter. Then doing it all over again with Dexron VI.
 


NotEnoughGPs said:
Ok. I have heard that in an old 4T65E with Dexron III, if one drops the pan, replaces the filter, and changes to Dexron VI, there is no great harm.
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AND

I have heard that in an old 4T65E with Dexron III, if one drops the pan, replaces the filter, and replaces it with new Dexron III, there is no great harm.
 
Getting some DEXIII in your DEXVI is not going to be an issue. I just remembered that I had a buddy change my trans fluid a few months back when he did my right CV shaft. He put in DEXVI, when I had DEXIII in before. The sky has not fallen yet. LOL
 
Mine has been on it's way out for 3 years now, it's got almost 3 quarts of Lucas and 2 quarts dex3, 2 quarts dex6 in it, plus whatever was originally in it...

It's lost pieces of what I'm guessing is the input clutch piston seal in the bottom of the pan, along with a very healthy amount of clutch material.

It's got a modified shift kit, along with a custom tune. It'll give me some attitude every once in a while, with a slight thump into 2nd and sometimes 3rd, and it only shudders when it's cold and coming out of neutral for the first time... but Scotty can confirm that the car drives just fine, he's seen my scans.

At this point, I'm inclined to say that it's nearly impossible to predict what will happen, but you should be fine with either 3 or 6.

Shift kit and a new filter most likely help more than hurt, with the fact that the car hasn't been abused and driven hard, and the original fluid is just simply old and not burnt or otherwise indicative of a problem.
 
There's too much data to ignore, DexIII for these Trans... And for the matter, companies like Amsoil, Royal Purple etc, that sell DexIII Trans Fluid aren't just coloring their product purple... Point is, yeah, go ahead, use DexVI, but the trans won't like it. I did on a rebuild, and dropped the pan not long after to change out as much of it as I could. It's a better blend sure, but the older trans don't like em... And you NEvER EVER, "EVER" flush these transmissions, did I say EVER? Well, not if you want it to last... Doesn't matter what type of fancy Schmancie machine you got, doesn't matter. Just add $1,500 to the cost of the flush.
 


Mike Kerr said:
Yes, DEX VI is more expensive. But, DEX VI at Wal Mart cost less than DEX III at Auto Zone....
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Yeah, most fluids are cheaper at Walmart than most of the parts stores. Unless they have a "sale". Sometimes the oriellys here has 5 quarts of quaker state and a filter for like $20.

Sent from a galaxy far far away.
 
NotEnoughGPs
I was over browsing the forums on GMFullsize and came across this thread http://www.gmfullsize.com/threads/how-to-4l60e-transmission-flush-filter-change.179148/
I know these instructions are for full sized GM trucks but the same concept applies to these cars, if I was you I would do what this guy did, just make sure you drop the pan and change your filter before adding in new fluid. Do note that the barbed fitting might be a different size on our radiators. I do not know what size the fitting is, but I am pretty sure a quick Google search should tell you the size of the fitting. Hope this helps.
 
The bottom line is that either Dexron III or VI will work in your tranny BUT Dexron VI is clearly a superior Trans fluid. Dexron III is no longer licensed by GM so you have no idea of the quality 0f Dexron III made by the aftermarket or if it truly meets GM's OEM specs for this fluid. If I was going to use III (which I don't...100,000 miles on Dexron VI and counting), I would only use one from a high quality manufacturer like Amsoil. Yes Dex VI has lower viscosity than III (which is a benefit in colder climates BTW and at cold start) but the conventional nature of Dex III fluid quickly reduces the viscosity of Dex III with little mileage to the viscosity of Dex VI when it is fresh/new...add the superior benefits like oxidation inhibition etc of the synthetic nature of Dex VI, and Dex VI is a clear winner and the reason Dex III was dropped by GM. Change your trans fluid/filter OFTEN (max is 25,000 miles), run a trans cooler OUTSIDE of the radiator, and the 4T65E will last a LONG time for a tranny with some design flaws.

As for the OP, I would drop the pan, change the fluid/filter (add a magnet or 2 in the pan) with DEX III (walmart-CHEAP) since there is no benefit at this point of running VI, run the tranny for 500- 1000 miles and do it all again. I would change the tranny/fluid once a year if the trans lives on......moving forward.

I would NOT do nothing and hope for the best...Hope is not a strategy.......................
 
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coolone said:
There's too much data to ignore, DexIII for these Trans... And for the matter, companies like Amsoil, Royal Purple etc, that sell DexIII Trans Fluid aren't just coloring their product purple... Point is, yeah, go ahead, use DexVI, but the trans won't like it. I did on a rebuild, and dropped the pan not long after to change out as much of it as I could. It's a better blend sure, but the older trans don't like em... And you NEvER EVER, "EVER" flush these transmissions, did I say EVER? Well, not if you want it to last... Doesn't matter what type of fancy Schmancie machine you got, doesn't matter. Just add $1,500 to the cost of the flush.
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I agree that Dexron VI is far superior. In the case of my car, I am going to use Valvoline Dex III, biggest reason is the car is not high performance, and I plan to run it easy going forward. Perhaps the next time I change it, I will convert to Dex VI (no, I won't wait until 241,000 miles next time. I will be lucky if the transmission works well enough to make it to 300K miles)
And it has been so advised to never use a flush machine on the 4T65E! I never planned to use one anyways.
 
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Slick2500 said:
NotEnoughGPs
I was over browsing the forums on GMFullsize and came across this thread http://www.gmfullsize.com/threads/how-to-4l60e-transmission-flush-filter-change.179148/
I know these instructions are for full sized GM trucks but the same concept applies to these cars, if I was you I would do what this guy did, just make sure you drop the pan and change your filter before adding in new fluid. Do note that the barbed fitting might be a different size on our radiators. I do not know what size the fitting is, but I am pretty sure a quick Google search should tell you the size of the fitting. Hope this helps.
Click to expand...

Thanks for the info. I read through this post last night, and I agree with you that I need to find a way to force all the old fluid out of the transmission (believe me, it is very dirty) Right here on this forum, in the "How to write-ups/tech tips" section, there is a thread called http://www.grandprixforums.net/thre...etailed-Pictures?highlight=transmission+fluid.
The author 02NavyBlue gives instructions on how to install the TransGo shift kit. At the end the of photos he put on the post, there is a picture of the return line. I located this line, and plan to put a hose on this line, and then start the engine to force out the old transmission fluid. I did pretty much everything else to this point (I have the IntenseRacing Shift Kit that I am going to install) I am going to finish this afternoon. But again, thanks for pointing out what I need to do!
 
Quick Update: As I stated before, I would let everyone know the condition of the transmission fluid in the pan. I lowered the pan and found no metal shavings or metal pieces. The fluid does not have the burnt smell that others said could mean the trans is near failing. However, the old trans fluid was quite dirty, a dark brown color.
In a few hours, I will proceed with installing an IntenseRacing shift kit, and adding Dexron III. Then to do a complete fluid exchange, I hope to be able to remove the return line going to the trans, and use the procedure to force out all the old trans fluid.
I will get back to ya later today!
 
NotEnoughGPs said:
Quick Update: As I stated before, I would let everyone know the condition of the transmission fluid in the pan. I lowered the pan and found no metal shavings or metal pieces. The fluid does not have the burnt smell that others said could mean the trans is near failing. However, the old trans fluid was quite dirty, a dark brown color.
In a few hours, I will proceed with installing an IntenseRacing shift kit, and adding Dexron III. Then to do a complete fluid exchange, I hope to be able to remove the return line going to the trans, and use the procedure to force out all the old trans fluid.
I will get back to ya later today!
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do not flush it after the pan drop or it can be dead before its put in drive. seen it a 100 times. never flush a high mile tranny with dark fluid. EVER!
 
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