98 Old 88 - Flush or Drain ATF?

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I bought this car used a year and a half ago used with 147,000 miles. It was a one owner and the guy took really good care of it. The ATF still looks clean today. I guess I have a couple questions. If it's still clean should I mess with it? I dont know when it was last changed. And when I do change it, is there any harm in having it flushed or should I do the pan drop, filter and just refill?
 
old transmission mechancis usually say drop pan and refill only,,,I do this on my 2005 buick ,no problems yet and I have had one trans rebuild 100,000 miles ago. total mileage is now 169K...
 
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We had a '69 Old Delta 88 in the family a long time ago.

If "the ATF still looks clean today" I'd just do a drain & fill.

You should have a filter handy as you'll be dropping the pan but don't be surprised to find it clean.

You've got "O-L-D-S Oldsmobility".
 
Ok...thank you. This trans runs good. It does have one issue with a worn out solenoid so it will have a long shift between 1,2 and 3rd gear...but I've found thar by accelerating just slightly quicker than normal helps it shift faster. I dont mean slamming on it, but just getting it up to spread a slight bit faster helps it. And it only ever seems to do this when the transmission gets good and warmed up.
 
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A few consecutive drain and fills with 500 between them. Get a Doorman pan with a drain plug. Makes life easier.
 
Originally Posted by Mark72
I bought this car used a year and a half ago used with 147,000 miles. It was a one owner and the guy took really good care of it. The ATF still looks clean today. I guess I have a couple questions. If it's still clean should I mess with it? I dont know when it was last changed. And when I do change it, is there any harm in having it flushed or should I do the pan drop, filter and just refill?


If its the original transmission the 4th gear input shaft will probably be the failure point in the not the too distant future regardless of fluid changes.
You can do a line off exchange on these very easily after dropping the pan and installing a new filter, you may as well install a shift kit while you are in there, it will help keep the P1811 code at bay.
Add a cooler to it and keep in in 3rd gear until your on the highway to help keep the 4th input shaft alive longer.

I have used Amsoil ATF in these with good results, Maxlife or dex VI blows in these IMO, they shift softer than a wet noodle. The higher viscosity synthetic ATF gives a slightly firmer shifts.

This is the US made filter you want..

https://shop.tripleedgeperformance.com/4T60E-65E-Filter-84710E.htm

You can reuse the original pan gasket a few times if it is still there.

The shift kit..

https://shop.tripleedgeperformance.com/Transgo-SK4T65E-Shift-Kit-K84908M.htm

Lots of good info on this transmission the 4T65E on the site.
 
If it's still clean then it's likely that it was serviced some time in the more recent life on the vehicle. If it was me I'd still service it anyway since the transmission is the weak point of that car. Since you don't know if the filter was changed I'd want to drop the pan and do that whether or not you flush the rest.

At least if you do it now you shouldn't have to worry about it for a long time (maybe the life of the vehicle).

In case the anti flush people show up, I just serviced my 2005 Silverado with 193k miles. Original fluid and filter. It was looking dark at 150k miles but it was black when I changed it. I started with a pan drop and filter change, drove it for a week, shifting was unaffected (shifts fine but not as crisp as I'd like). After a week I had the shop fix the leaking cooler lines and flush another 10qts. He told me it was coming out black even after the 6qts of fresh stuff I put in with the pan drop. I used dexron 6 (Castrol trans max) the shop used qmi multi vehicle synthetic.

It started shifting slightly better after the flush, no issues and the fluid is still looking clean. This is not the first time I've flushed a neglected high mileage transmission and I've never had a transmission issue. We also did it in all the shops I worked at and can't remember any vehicles come back with a failed transmission from servicing it.
 
Originally Posted by Trav
Originally Posted by Mark72
I bought this car used a year and a half ago used with 147,000 miles. It was a one owner and the guy took really good care of it. The ATF still looks clean today. I guess I have a couple questions. If it's still clean should I mess with it? I dont know when it was last changed. And when I do change it, is there any harm in having it flushed or should I do the pan drop, filter and just refill?


If its the original transmission the 4th gear input shaft will probably be the failure point in the not the too distant future regardless of fluid changes.
You can do a line off exchange on these very easily after dropping the pan and installing a new filter, you may as well install a shift kit while you are in there, it will help keep the P1811 code at bay.
Add a cooler to it and keep in in 3rd gear until your on the highway to help keep the 4th input shaft alive longer.

I have used Amsoil ATF in these with good results, Maxlife or dex VI blows in these IMO, they shift softer than a wet noodle. The higher viscosity synthetic ATF gives a slightly firmer shifts.

This is the US made filter you want..

https://shop.tripleedgeperformance.com/4T60E-65E-Filter-84710E.htm

You can reuse the original pan gasket a few times if it is still there.

The shift kit..

https://shop.tripleedgeperformance.com/Transgo-SK4T65E-Shift-Kit-K84908M.htm

Lots of good info on this transmission the 4T65E on the site.


I agree with the shift kit now that I see it has a delayed shift. I don't know about the Dex 6 complaints.... Never experienced that though I haven't tried it in a 4t60 or 65.

Dexron 6 shifts awesome in my 270k mile gm 2004R but I believe it has a shift kit. I ran into the previous owner who sold me the car it came in way back in 2002, he says they "had to replace the governor" but it sure feels like the shop who did it put a shift kit in (probably because he towed a boat with it). Either way it and my other high mileage 2004R both shift fine on dex 6.
 
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Originally Posted by Mark72
Ok...thank you. This trans runs good. It does have one issue with a worn out solenoid so it will have a long shift between 1,2 and 3rd gear...but I've found thar by accelerating just slightly quicker than normal helps it shift faster. I dont mean slamming on it, but just getting it up to spread a slight bit faster helps it. And it only ever seems to do this when the transmission gets good and warmed up.


My truck is like that too, the computer wants the mushiest shifts when you drive it like grampa but if you accelerate a bit harder it gets a lot crisper. I'd like a shift kit so it just shifts like that all the time.
 
What's crazy is when you talk about the 4th gear being the failure point. It must have a ghost in it. I've driven this car to San Antonio Texas and back twice last summer. Blazing hot, humid, traffic jams on interstate....ran perfect
 
If your transmission doesn't have a drain plug, get an aftermarket pan that has one. This will make future ATF changes much easier
smile.gif
 
Originally Posted by Mark72
What's crazy is when you talk about the 4th gear being the failure point. It must have a ghost in it. I've driven this car to San Antonio Texas and back twice last summer. Blazing hot, humid, traffic jams on interstate....ran perfect


Doesn't mean some of them won't last 200k, 250k or even 300k before that or any failure. Fixing that delayed shift should help delay any impending failure.
 
Originally Posted by atikovi


Used an AC Delco filter and threw out the hard gasket.


Not the smartest move! That RTV crap is nowhere near as good as the steel core OE reusable gasket.

Originally Posted by Mark72
What's crazy is when you talk about the 4th gear being the failure point. It must have a ghost in it. I've driven this car to San Antonio Texas and back twice last summer. Blazing hot, humid, traffic jams on interstate....ran perfect


Driving it on the highway is not a problem for the 4th gear input shaft, once its in gear it stays there. They used a shaft that the teeth were not hardened and stripped easily over time, the more use the more wear there is on them, in 03-04 they used a hardened shaft.
 
Wasn't taking the chance of reusing a 25 year old gasket no matter how reusable they say they are when RTV gives a superior seal. The only reasons techs don't like them is because it takes more time and effort to use it; cleaning off both surfaces and a steady hand to apply.
 
Originally Posted by Trav
Originally Posted by Mark72
I bought this car used a year and a half ago used with 147,000 miles. It was a one owner and the guy took really good care of it. The ATF still looks clean today. I guess I have a couple questions. If it's still clean should I mess with it? I dont know when it was last changed. And when I do change it, is there any harm in having it flushed or should I do the pan drop, filter and just refill?


If its the original transmission the 4th gear input shaft will probably be the failure point in the not the too distant future regardless of fluid changes.
You can do a line off exchange on these very easily after dropping the pan and installing a new filter, you may as well install a shift kit while you are in there, it will help keep the P1811 code at bay.
Add a cooler to it and keep in in 3rd gear until your on the highway to help keep the 4th input shaft alive longer.

I have used Amsoil ATF in these with good results, Maxlife or dex VI blows in these IMO, they shift softer than a wet noodle. The higher viscosity synthetic ATF gives a slightly firmer shifts.

This is the US made filter you want..

https://shop.tripleedgeperformance.com/4T60E-65E-Filter-84710E.htm

You can reuse the original pan gasket a few times if it is still there.

The shift kit..

https://shop.tripleedgeperformance.com/Transgo-SK4T65E-Shift-Kit-K84908M.htm

Lots of good info on this transmission the 4T65E on the site.

Good info. Like to add, I have used this low cost item to resolve an issue with the 4T60E/65E transmissions.

https://www.sonnax.com/parts/2534-differential-lube-tube-retainer-kit

You may also want to check out TSB 08-07-30-040B There is an upgrade to the oil pan magnet. Part# 29535617 , I get them at Rock Auto.

https://www.rockauto.com/en/parts/acdelco,29535617,oil+pan+magnet,18538
 
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Originally Posted by atikovi
Wasn't taking the chance of reusing a 25 year old gasket no matter how reusable they say they are when RTV gives a superior seal. The only reasons techs don't like them is because it takes more time and effort to use it; cleaning off both surfaces and a steady hand to apply.


I use both usually. The new gasket that comes with the filter kit and some RTV.
 
You have two leak points from a solid gasket, on one side and then from the other side of the gasket. With RTV virtually bonding to the case and pan, you theoretically have no leak points.
 
Originally Posted by atikovi
You have two leak points from a solid gasket, on one side and then from the other side of the gasket. With RTV virtually bonding to the case and pan, you theoretically have no leak points.

Never use RTV especially on an oil pan and don't use it along with a gasket.. If surfaces are perfectly clean and you don't do everything perfectly, it will leak and tweeking the pan bolts will make it leak more. Don't know where you get this two leak point stuff only with a gasket, RTV has to bond to the pan and the case, that's two to me. The original gasket is reusable and I have used mine over twice without any leaks. The secret is making sure the sealing flange of the pan is flat.
 
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Originally Posted by Lubener
Never use RTV especially on an oil pan and don't use it along with a gasket.


You might want to ask yourself then, why have most of the major car manufacturers gone to RTV instead of solid gaskets.
 
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