I am asking an obvious, but curious question. I have heard from my Father, who off roads Cherokee's,that it is not recommend to drain your tranny fluid and change the filter, because it wil actually do more harm than good. My question is about my 98 blazer. I am nottheoriginal owner and would like to change the fluid, but am nervous. Is there right for me to fear the fluid change and for me to worry about a perfectly functioning tranny. I also want to add a tranny cooler any suggestions on this topic?

 

I Have the fluid exchanged and a new filterreplaced at a transmission shop every25-30K miles. (need it or not). Some people think the fluid exchange is a bad Idea when the trans has lot's of miles on them (over 100,000) because of the high detergent content in trans fluid. If your unsure weather the previous owner ever changed it or not, then simply drop the trans pan and change the filter, refill with 4-5 quarts offresh fluid and your good to go for a while.

 

I wouldn't be worried about a pan drop and filter change. You just have to make sure that you do not damage the seal for the filter up in the transmission. If in doubt, you'll have to remove the old seal and install the one that comes with the new filter. Most of the time you won't have a problem reusing the old seal, but use some trans fluid on the tube that slides into the seal to ensure that it does not get damaged.

I now have a B&M transmission drain plug installed in my '01 Bonneville SSEi and once I get some time to drop the pan on my Bravada, I'll be installing one in its pan as well. Then all I have to do is pull the plug every 20k miles, let it drain, and fill it back up. There really isn't much of a reason to replace the filter unless you have the pan off already. With a drain plug, just drain the all of the old fluid that will come out and refill.

If you do go the drain plug route, you may want to drain it again within 5k miles or so after the installation of the plug just to cycle out most all of the old fluid.

 

If the vehicle has allot of miles on it and the fluid looks like you pulled the engine dipstick on accident then I probably would not change it, because you could cause a problem. I see no problem changing the fluid though. I have never seen a problem stem from a trans service, unless there was a problem lurking in the trans already. Maintain away my friend!!

 

Hey Swartlkk Bout that drain plug install. How did you do it and what was used. Whenever I did a tune up (or work in general) I took the pan off and changed the filter while off. Be nice not to have to remove the pan EVERY time.

Sorry for the hyjack Guys

 

Dabber,
Here's Every part you ever wanted to know aboutyour 4L60e, But were afraid to ask....

 

The drain plug just requires a drilled hole and the drain plug. I forget what size the hole is, but it wasn't all that large. I just drilled and deburred the hole, then used some Loctite 271 on the threads on the side that holds the whole assembly into the pan. Let it sit for a few hours before putting it back on and filling it up. It is just a fitting that has a 1/4" pipe plug into it. Still gets most of the fluid out of the pan.

You can buy pans that have an integrated drain plug, but most of them are aluminum which is nice, but big $$$. I think there are a few that are chromed stamped steel and can be purchased for around $60-$70. I don't know how confident I'd be in the threads on the stamped pans unless there is a lug inside that is welded in.

 

well i believe my tranny is stock..not 100 percent sure..but i drained and filled it and there were no issues

 

My drain plug was free, I had a spare oil drain plug for the blazer, then I found the correct nut for it. I then drilled a hole in my pan, and welded the nut to the inside of my trans pan, and tightened up the drain plug. Put 'er all back together, and filled 'er up!!