1995 4L60E fluid question

blackwarbeast · 02-18-2009, 07:34 AM

My 1995 gmc 1500 has 152k on it and I dont know when the transmission fluid and filter were changed last. The fluid color does not appear to be burnt but I would like to do something just to know that its been done. I was thinking of replacing the trans filter. I read somewhere that its best to introduce new fluid into it one quart at a time. My question is, is that true? also, how would I go about doing so? Would I simply remove the drain pan and pour 1 quarts worth into a seperate container and then pour in 1 new quart? I would really like any pointers in concern with this because im very intimidated by transmissions as ive never done anything to one before and this truck is my daily driver. Also I believe this truck has a trans cooler mounted in front of the radiator, im not sure yet though because I havent traced the lines back to where they go.

bradrhale · 02-18-2009, 09:51 AM

never heard doing it one quart at a time. there is an old tale that if there are alot of miles on one, you always put the existing fluid back in there. but this i believe is exactly that and no more than just an old tale. drain it, take the pan down, replace the filter and reinstall. follow your owners manual on the amount to put back in. remember that this is not a full change so dont put in what they say is the max. alot of fluid stays inside of the converter and cannot be changed unless you take everything apart. but you should be ok.

blackwarbeast · 02-18-2009, 11:18 AM

Thanks...so if I just drain whats in the pan and ill be mixing new fluid with the old fluid thats still in the converter...should I put regular dexron III in it rather than say full synthetic dexron III? also, im using a filterdot on my trans pan so should I clean the pan out real good while its dropped?

z07 · 02-18-2009, 11:34 AM

Do clean the pan. Pay particular attention to the magnets. A little bit of metal is normal but if it looks like someone dumped a whole coffee filter in there then it's time to budget for a rebuild.

The only way to change all the old fluid is with a complete teardown of the whole system and flush of the cooler/radiator and lines.

The common way to get close to a complete change is to replace the filter and do a 20 quart flush using the in and out lines at the radiator. You really need the machine that the lube shops use to do this well. This is the proceedure that they will make you sign a waiver for because they want to cover themselves. Most people only have this done when the trans is already slipping and the lube shop doesn't want anyone coming back to them saying the flush caused the problem. The flush CAN cause the problem if they let fluid pump out much faster than it's replaced.

In any case, when you have the new fluid in, don't just drive the truck off the ramps. You will want to start the truck hold it in park for 30 seconds and then work your way to each gear and hold it there for 30 seconds before you drive off. P R N skip to 1 2 3 OD.

blackwarbeast · 02-18-2009, 12:43 PM

Ok thanks for the additional information and what to look for. I will be dropping the pan in a week or two to change the filter. I dont trust getting a full flush from a shop at the moment so I will just do a filter change. The trans shifts fine and everything but id like to do it as preventive maintenance. Since im just dropping the pan what will be the best fluid to go with? Since it will be mixing with old fluid...

z07 · 02-18-2009, 01:11 PM

Quote:

Originally Posted by blackwarbeast

what will be the best fluid to go with?

That's a religious question

I like Mobil 1 full synthetic ATF.

DEXRON IV is compatible with all previous specs. It replaces and mixes with them too. Just make sure you put in DEXRON certified fluid and you're ok.

BTW do make sure the little o-ring comes out with the old filter. You don't want to put the new filter in with its o-ring while the old o-ring is still in place.

blackwarbeast · 02-18-2009, 01:20 PM

Quote:

Originally Posted by z07

That's a religious question

I like Mobil 1 full synthetic ATF.

DEXRON IV is compatible with all previous specs. It replaces and mixes with them too. Just make sure you put in DEXRON certified fluid and you're ok.

BTW do make sure the little o-ring comes out with the old filter. You don't want to put the new filter in with its o-ring while the old o-ring is still in place.

Ok good to know, since I use other Mobile 1 stuff. So the full synthetic ATF will mix with whatever may be left in the system after the pain is drained? (Say it has non-synth fluid in it right now..)

z07 · 02-18-2009, 01:24 PM

Quote:

Originally Posted by blackwarbeast

Ok good to know, since I use other Mobile 1 stuff. So the full synthetic ATF will mix with whatever may be left in the system after the pain is drained? (Say it has non-synth fluid in it right now..)

Yes. Mobil 1 Full syn ATF will mix with what's in there now just fine.

blackwarbeast · 02-18-2009, 01:32 PM

Awesome, thanks!

gmctrucks · 02-19-2009, 08:16 AM

I know on our 91 MPV we disconnected the pressure line at the cooler and drained a gallon out well we did that four times then I did the transmission filter service filter and all it came out super red which I like very much.
Good luck! GMC
PS-After I drained one gallon of coarse I added a gallon of clean fluid I didn't want to burn up the trans. I hope you under stood this because I sometimes don't under stand my self. I'm not kidding.

02-18-2009, 07:34 AM	#1
blackwarbeast Senior Member Join Date: Feb 2009 Posts: 52	1995 4L60E fluid question My 1995 gmc 1500 has 152k on it and I dont know when the transmission fluid and filter were changed last. The fluid color does not appear to be burnt but I would like to do something just to know that its been done. I was thinking of replacing the trans filter. I read somewhere that its best to introduce new fluid into it one quart at a time. My question is, is that true? also, how would I go about doing so? Would I simply remove the drain pan and pour 1 quarts worth into a seperate container and then pour in 1 new quart? I would really like any pointers in concern with this because im very intimidated by transmissions as ive never done anything to one before and this truck is my daily driver. Also I believe this truck has a trans cooler mounted in front of the radiator, im not sure yet though because I havent traced the lines back to where they go.

02-18-2009, 11:34 AM	#4
z07 Senior Member Join Date: Feb 2008 Posts: 391	Do clean the pan. Pay particular attention to the magnets. A little bit of metal is normal but if it looks like someone dumped a whole coffee filter in there then it's time to budget for a rebuild. The only way to change all the old fluid is with a complete teardown of the whole system and flush of the cooler/radiator and lines. The common way to get close to a complete change is to replace the filter and do a 20 quart flush using the in and out lines at the radiator. You really need the machine that the lube shops use to do this well. This is the proceedure that they will make you sign a waiver for because they want to cover themselves. Most people only have this done when the trans is already slipping and the lube shop doesn't want anyone coming back to them saying the flush caused the problem. The flush CAN cause the problem if they let fluid pump out much faster than it's replaced. In any case, when you have the new fluid in, don't just drive the truck off the ramps. You will want to start the truck hold it in park for 30 seconds and then work your way to each gear and hold it there for 30 seconds before you drive off. P R N skip to 1 2 3 OD. Last edited by z07; 02-18-2009 at 01:15 PM.

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02-18-2009, 09:51 AM	#2
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,511	never heard doing it one quart at a time. there is an old tale that if there are alot of miles on one, you always put the existing fluid back in there. but this i believe is exactly that and no more than just an old tale. drain it, take the pan down, replace the filter and reinstall. follow your owners manual on the amount to put back in. remember that this is not a full change so dont put in what they say is the max. alot of fluid stays inside of the converter and cannot be changed unless you take everything apart. but you should be ok.

02-18-2009, 11:18 AM	#3
blackwarbeast Senior Member Join Date: Feb 2009 Posts: 52	Thanks...so if I just drain whats in the pan and ill be mixing new fluid with the old fluid thats still in the converter...should I put regular dexron III in it rather than say full synthetic dexron III? also, im using a filterdot on my trans pan so should I clean the pan out real good while its dropped?

02-18-2009, 12:43 PM	#5
blackwarbeast Senior Member Join Date: Feb 2009 Posts: 52	Ok thanks for the additional information and what to look for. I will be dropping the pan in a week or two to change the filter. I dont trust getting a full flush from a shop at the moment so I will just do a filter change. The trans shifts fine and everything but id like to do it as preventive maintenance. Since im just dropping the pan what will be the best fluid to go with? Since it will be mixing with old fluid...

02-18-2009, 01:32 PM	#9
blackwarbeast Senior Member Join Date: Feb 2009 Posts: 52	Awesome, thanks!

02-19-2009, 08:16 AM	#10
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,646	I know on our 91 MPV we disconnected the pressure line at the cooler and drained a gallon out well we did that four times then I did the transmission filter service filter and all it came out super red which I like very much. Good luck! GMC PS-After I drained one gallon of coarse I added a gallon of clean fluid I didn't want to burn up the trans. I hope you under stood this because I sometimes don't under stand my self. I'm not kidding.