Pan Drop or Fluid Through Dipstick

[TheLawnRanger]

I have an Impala at around 125000 miles and a Colorado at around 135000 miles. As far as I know, the ATF has never been changed. At this point, would it be better to do a pan drop and refill plus change the filter or extract a quart at the time and replace it through the dipstick? I know there can be problems changing out too much ATF at a higher mileage.

 

[Warstud]

Extract as much out of the dipstick tube as you can. Do that about 2-3 times then drop the pan....replace the filter and filler up. What kind of extractor do you have?

 

[92saturnsl2]

I'm an advocate of semi-frequent fluid changes (every 30-50k for autos). Pan drop on these should allow you to replace the filter, and it's not all the terrible a procedure, just a bit messy. Once you replace the filter, you could consider just a fluid refresh.

Unless there's presently something wrong with the transmission, I see no reason not to change.

 

[RF Overlord]

Originally Posted By: TheLawnRanger
I know there can be problems changing out too much ATF at a higher mileage.
The old wive's tale that refuses to die.

If a transmission develops issues soon after a fluid change, it was on its last legs and would have failed shortly anyway. Unless the current fluid is brown/black/smelly definitely get it changed...fresh fluid is the lifeblood of any automatic transmission.

 

[kschachn]

Originally Posted By: TheLawnRanger
I know there can be problems changing out too much ATF at a higher mileage.

Do you know that or did you just read it on the Internet?

 

[Crispysea]

I usually pump it out through the dipstick tube. It depends on the vehicle, though. I change a gallon or so at a time, and do it again after 5-10k miles. After two or three times, it’s clean.

 

[Leo99]

Originally Posted By: kschachn
Originally Posted By: TheLawnRanger
I know there can be problems changing out too much ATF at a higher mileage.

Do you know that or did you just read it on the Internet?


The owner of a local transmission shop told me the same while we were chatting offline.

 

[WobblyElvis]

These are high mileage vehicles on the original filters. Why would you not change the filter? Drop and clean the pan, change the filter, refill and you're good to go.

 

[JeffKeryk]

If the pan does not have a drain plug, I would install one while you are at it. Soooo much easier going forward.

 

[MaximaGuy]

No need for pan drops - you will NOT find anything out of the ordinary from dropping the pan, period.
Only heartburn in getting those insane number of bolts torqued right with the right dance.
Drain and fill or better off return line flush by disconnecting the line at the end of the radiator.

Both your vehicles are NEW even with 100K, these ATFs are designed to keep the transmission running well for a long time, you are NOT going to find anything by dropping the pans.

 

[slacktide_bitog]

Originally Posted By: JeffKeryk
If the pan does not have a drain plug, I would install one while you are at it. Soooo much easier going forward.

Dorman is the most popular aftermarket pan, but there may be a few others too

 

[JustN89]

I tried to extract the fluid from the dipstick on my 2005 Impala. It would only pull out about 3.5 quarts. I dropped the pan and probably another 1.5 quarts or so came out (hard to tell because I also pulled the filter and installed a shift kit). In all, it took just under 8 quarts to fill up. I installed a Dorman pan so that I would have a drain plug next time.

 

[demarpaint]

Originally Posted By: Warstud
Extract as much out of the dipstick tube as you can. Do that about 2-3 times then drop the pan....replace the filter and filler up. What kind of extractor do you have?

When removing a line for a line off exchange is difficult for whatever reason, that's how I do it.

 

[littleant]

Pan drop and refill and change the filter. 125,000-135,000 Thats a lot of miles on the fluid.

 

[PiperOne]

You don't have "higher mileage" vehicles..just getting broken in

. That said...drop the pan and change the filter and fluid, refill with a full syn DEX (6 or HP, whatever is specified) and go another 100,000 miles. Whatever you do...don't ever use any "flush" chemicals or any kind of flushing machine on these units. Regular 100,000 fluid filter changes with a good DEX fluid and the transmissions will live a very long happy life. We easily get 400,000 miles plus out of work truck GM transmissions with this philosophy (albeit with a 50,000 drain on the bigger stuff).

 

[MasterSolenoid]

Originally Posted By: littleant
Pan drop and refill and change the filter. 125,000-135,000 Thats a lot of miles on the fluid.


I agree.
And CLEAN the Magnet.

 

[eljefino]

I tried using aquarium tubing on my 3t40 and it got caught on the bottom of the dipstick tube, where it transitions to the pan. Only got a quart out.

Get a kiddie wading pool for $7 from K-mart and drop the pan. You're gonna make a mess. Obviously, use a better oil drain pan where you think your mess will be, but, there'll be a splash zone outside of that.

Once you do a pan drop once you'll be better at it the second time around, as far as knowing which two bolts should be pulled last so you can point the mess.

Incidentally I "saved" a weak 4T60 that was full of grey silt, blocking the filter, reducing pressure, and causing slippage by changing the oil, filter, and modulator.

 

[barkingspider]

I dropped the pan on my GMC at 81k miles, replaced filter, did the trans cooler line fluid pump out and installed an aftermarket trans cooler. So I have all new fluid (Castrol Dex 6). Will probably run it for 80k-100k miles. I recommend you do a pan drop, filter replace and cooler line fluid so you have 100% new Dex 6

 

[Trav]

When I do the 4T65E I do a pretty thorough service on them, how comfortable are you doing very small easy jobs inside the transmission? If you are I will do a detailed write up, if not I will answer pan drop and change the filter and refill.

 

[TheLawnRanger]

Originally Posted By: Trav
When I do the 4T65E I do a pretty thorough service on them, how comfortable are you doing very small easy jobs inside the transmission? If you are I will do a detailed write up, if not I will answer pan drop and change the filter and refill.


I would appreciate the detailed write up. I've not done a lot if this type of work but if it's several small easy jobs, I think I could do it.