Tranny Flush

I have a question about flushing the Tranny. On several occasions i have seen people post not to flush the tranny. Just change filter and fluid. Can someone explain this to me? I was actually thinking about a tranny flush. I have a 98 custom with 71,000 miles on it and was thinking that a flush might be good.

Also, I've read somewhere that its a good idea to reuse the old gasket? Does anyone know anything about this as well?

Thanks ;)

I have a question about flushing the Tranny. On several occasions i have seen people post not to flush the tranny. Just change filter and fluid. Can someone explain this to me? I was actually thinking about a tranny flush. I have a 98 custom with 71,000 miles on it and was thinking that a flush might be good.

Also, I've read somewhere that its a good idea to reuse the old gasket? Does anyone know anything about this as well?

Thanks ;)

I have been planning to do an ATF Fluid & Filter change to my 98 Le Sabre. After a lot of reading on this forum and others I came to the conclusion that a number of people have had negative experiences with older transmissions when doing a flush. It seems that too much of a good thing too fast can cause problems. I decided to drop the pan and go the old fashioned route but follow up with more frequent fluid changes using extraction through the dipstick. As far as the gasket goes it looks like the GM version is reusable but after 9 years I worry that the gasket may need replacing due to damage or aging. The manual says “Use a new gasket if the sealing ribs are damaged.” So to be on the safe side I went to the dealer for the filter and gasket. There are two possibilities for the gasket since GM changed the pan bolts from 8mm to 6mm during the 98 model year. I pulled one of the bolts and the shank was 6mm on mine. Here are the part numbers from the dealer.
Filter P/N: 24227477 $39.58
Gasket 6mm bolts P/N: 24206182 $43.21
Gasket 8mm bolts P/N: 24204624 $44.02

I have been planning to do an ATF Fluid & Filter change to my 98 Le Sabre. After a lot of reading on this forum and others I came to the conclusion that a number of people have had negative experiences with older transmissions when doing a flush. It seems that too much of a good thing too fast can cause problems. I decided to drop the pan and go the old fashioned route but follow up with more frequent fluid changes using extraction through the dipstick. As far as the gasket goes it looks like the GM version is reusable but after 9 years I worry that the gasket may need replacing due to damage or aging. The manual says “Use a new gasket if the sealing ribs are damaged.” So to be on the safe side I went to the dealer for the filter and gasket. There are two possibilities for the gasket since GM changed the pan bolts from 8mm to 6mm during the 98 model year. I pulled one of the bolts and the shank was 6mm on mine. Here are the part numbers from the dealer.
Filter P/N: 24227477 $39.58
Gasket 6mm bolts P/N: 24206182 $43.21
Gasket 8mm bolts P/N: 24204624 $44.02

Thanks for the info.....I guess i'll go your path as well. Just change fluid, filter , & gasket.

P.S. How many miles do you have on your '98 and how is it running?

Thanks for the info.....I guess i'll go your path as well. Just change fluid, filter , & gasket.

P.S. How many miles do you have on your '98 and how is it running?

48K - and you answered my question about the UIM & LIM on the other thread. It's running good and I hope to keep it that way.

48K - and you answered my question about the UIM & LIM on the other thread. It's running good and I hope to keep it that way.

Oh, that was you. LOL

Most times i just read the posts without even looking at the posters names. Silly me.

I wouldnt do a complete flush but i would change the filter once then again in a few thousand miles depending on how dirty it is and if it was ever changed before. Just because with the new fluid it will clean out the tranny and your filter will fill up with dirt and debris and the second filter change will ensure it is flowing freely and still cleaning up the fluid. I have done this with my trannys and i had alot more miles then you do on yours and had good luck. I do believe a complete flush will shock the tranny and possibly clog your filter. Removing some of the fluid through your dipstick tube is a good idea to put more new fluid in but remember your filter is what keeps it all clean. And if you have extra money to spend it is a good idea to use semi-synthetic fluid on your first change because it has more cleaning agents than regular fluid.