4L80e fluid change

[454cid]

I pulled the pan and filter on my 4L60E one time, put the pan back on and left it overnight. In the morning there was damn near a quart of fluid in the pan--and it was STILL dripping fluid......geeez.

Ok, maybe I was wrong then.... I never suspected it would be that much dripping out of there.

 

[Supercharged111]

Drop a cooler tube, aim the open end into a drain pan. Start the engine. When the fluid starts to sputter, shut off the engine.

Drop the now nearly-empty pan, clean the pan and magnet, replace the filter, reinstall and seal the pan with a good gasket--which might be the reusable one already on the vehicle. Torque pan bolts as needed.

Dump five quarts of fresh fluid down the dipstick tube, open about ten more quarts and place them within easy reach so you can dump them quickly down the dipstick tube.

Start engine, watch the fluid coming out of the cooler tube and dump the opened quarts of fluid into the trans as fast as it will flow out of the funnel down the tube. When the fluid shooting out the cooler tube looks virgin-new, shut off the engine. Reconnect the cooler tube. Start engine, adjust fluid level as needed. ("Full" when HOT, a little less than that initially.)

Pack up the old fluid for recycling. Most of the time, I pour it from the drain pan into the empty bottles so it doesn't slosh out of the drain pan and mess up the bed of the truck, or the carpet in the trunk of the car. In my case, it becomes fire-starter in the winter; but before I had a fireplace it went to various recycling centers; or to shops that had a waste-oil furnace.

Done. Feel proud about flushing 95% or more of the fluid from your transmission. Open and enjoy a celebratory beverage.

When dropping the cooler tube, pay attention to normal fluid flow--so that you aim the correct tube into the drain pan. In some cases, I've gone so far as to make a short, temporary tube to plug into the outlet port of the cooler, to aim into the drain pan. That way I flush the cooler, too.

This is the way to do it. I've done it multiple times. I had done 3 or 4 fluid drain/refills on my 4L60 before it died and the fluid NEVER came out clean. I did this method and 6 months later when it gave up the ghost it was still cherry red. I ended up cracking the case, so not a clutch failure to pollute the fluid.

 

[Jack Nichols]

When I first bought my '92 Silverado 1 ton 3 yrs ago, I drained the tranny, dropped pan and noticed the pan had a flat spot where it looks like a drain bung should have been drilled. So I drilled one, welded nut outside and then after reassembly I put in new fluid and filter, drove a few dozen miles, drained again through my new bung drain hole and refilled. Best thing I ever did when it comes to servicing this 480 tranny. No leaks, no dropped pan mess.

 

[alpinecrick]

When I first bought my '92 Silverado 1 ton 3 yrs ago, I drained the tranny, dropped pan and noticed the pan had a flat spot where it looks like a drain bung should have been drilled. So I drilled one, welded nut outside and then after reassembly I put in new fluid and filter, drove a few dozen miles, drained again through my new bung drain hole and refilled. Best thing I ever did when it comes to servicing this 480 tranny. No leaks, no dropped pan mess.

Ding ding ding for the winner!!!!

They're getting tired of hearing this......pull the trans pan plug every 2nd or 3rd motor oil change, refill as needed. Thereby keeping the fluid fresh.

Goes a long ways towards longer lived auto transmissions of any sort.

 

[stutaeng]

Well, I finally motivated myself to do this. I had a spare transmission cooler line laying around and I cut it off and put my vinyl tubing with a hose clamp, and lay it down into a bucket.

After starting to get bubbles in the hose I shut off the engine. Dropped the pan, removed filter, popped that little sealing ring. I had another pan with the drain plug laying around, so I installed that one. Reused that thick rubber gasket.

Added about a gallon of fluid, then started the engine and simulataneusly added another gallon of fluid while watching the bright red fluid coming out of the tubing. Shut off the engine and reconnected the cooler line. Probably added another 3-4 qts. of fluid, and ran it through all the gears. Truck has right around 250k. I bought it with 230k almost 2 years ago. The P.O. towed his show car to car shows across the country is what he told me.

I got 3 other 4L80e's in the stable, so will need to get more of those 5 gallon buckets of that fluid to go through all of them.

 

[Caman96]

You should check out these gaskets.

Moroso 93104 Moroso Transmission Pan Gaskets | Summit Racing

Free Shipping - Moroso Transmission Pan Gaskets with qualifying orders of $109. Shop Transmission Pan Gaskets at Summit Racing.

www.summitracing.com

 

[Supercharged111]

You should check out these gaskets.

Moroso 93104 Moroso Transmission Pan Gaskets | Summit Racing

Free Shipping - Moroso Transmission Pan Gaskets with qualifying orders of $109. Shop Transmission Pan Gaskets at Summit Racing.

www.summitracing.com

Sounds like a good 2nd to the factory stuff. If the pan rail is flat, the gasket needs 1 or more ribs. If the pan rail has a rib, it needs a flat gasket.

 

[stutaeng]

Sounds like a good 2nd to the factory stuff. If the pan rail is flat, the gasket needs 1 or more ribs. If the pan rail has a rib, it needs a flat gasket.

I didn't see an option from Moroso for the 4L80e, but only went through the first of 9 pages on summit racing...not that I really "need" a $100 gasket, LOL. I had a cork and a thin rubber gasket that came with the filter, but just reused the one that was on there with those rivet eyelets over the holes...you know the ones.


You say some of these pan rails have ribs? The ones I own are all flat, but not an expert by any means. Could that be for the TH400 pans? Maybe I haven't paid enough attention, LOL.

 

[Supercharged111]

I didn't see an option from Moroso for the 4L80e, but only went through the first of 9 pages on summit racing...not that I really "need" a $100 gasket, LOL. I had a cork and a thin rubber gasket that came with the filter, but just reused the one that was on there with those rivet eyelets over the holes...you know the ones.


You say some of these pans have ribs? The ones I own are all flat, but not an expert by any means. Could that be for the TH400 pans?

Stock pans have flat rails, so they have the reusable ribbed factory gasket. You did the right thing by keeping the original gasket.

 

[Caman96]

I didn't see an option from Moroso for the 4L80e, but only went through the first of 9 pages on summit racing...not that I really "need" a $100 gasket, LOL. I had a cork and a thin rubber gasket that came with the filter, but just reused the one that was on there with those rivet eyelets over the holes...you know the ones.


You say some of these pan rails have ribs? The ones I own are all flat, but not an expert by any means. Could that be for the TH400 pans? Maybe I haven't paid enough attention, LOL.

You’re right, they don’t seem to make this for 4L80E. Good news is you have a 4L80E! For those of us with a 4L60E this is a great gasket.