2002 2500HD Transmission Swap

MVP9182 · July 14, 2016

I recently bought a 2002 Chevy 2500HD with a 6.0L. It has a rebuilt title but only cost $3000 so I figured it was worth a gamble! If it turned out to be junk I was sure I could that much if I parted it out. But anyway the guy said the motor was replaced in it when it was rebuilt but made no mention to the transmission other than it had a new tranny cooler. When I took it down to get an oil change today at Jiffy Lube, the guy said it didn't look like the 4L80e because it had a drain plug in the pan. He said it looked more like an aftermarket replacement that was designed to fit a few different motors and just plug any holes you don't use. Now I know that the Jiffy Lube guys aren't always the best ones to get this sort of insight from but it actually seemed to make sense. When it was rebuilt could someone put something other than the 4L80e in it and what would it be? Or is it more likely its just an aftermarket pan? And is there any casting numbers on the case that I could look for to see for sure what it is? Thanks!

Formulabruce · July 14, 2016

picture of the pan is needed... hard to imagine its not an 80, but if 2WD anything is possible

MVP9182 · July 14, 2016

Sorry for being at a weird angle. That's the best I could get without jacking the truck up

Raptordude · July 15, 2016

I have a 2001 Silverado 2500HD with the gas 6.0. It has the 4L80E transmission. My grandpa owned it since it was new so I know the tranny wasn't swapped. Mine DOES have a drain bolt, must be factory

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MVP9182 · July 15, 2016

I have a 2001 Silverado 2500HD with the gas 6.0. It has the 4L80E transmission. My grandpa owned it since it was new so I know the tranny wasn't swapped. Mine DOES have a drain bolt, must be factory

Was this an option from the factory? I didn't think any of the transmissions from 1999 to 2006 had a drain plug on them

Raptordude · July 15, 2016

It must be.....surprised me too, but I know my truck has the 4L80E and I know it wasn't ever modified

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Formulabruce · July 15, 2016

The picture above is a 4L80E , and they have drain plugs.. The original gasket is THE best pan gasket so always save it if you do a service.

in '04 it got some internal updates which are good to do if you get a rebuild

MVP9182 · July 15, 2016

Really surprising that it is 4L80E. And a huge plus that it has a drain plug! But the guy at Jiffy Lube said the transmission fluid was about 2 quarts over? So if it is actually a 4L80E should I drain some out? I don't do any towing or hauling but drive around 120ish miles a day and the transmission temp hasn't gone past 200 and rarely gets close to that now that I went down from 285 to 265 tires. Or is it best to leave well enough alone and just drive it?

davester · July 16, 2016

Check the fluid level yourself before draining any out.

Get the transmission warm , then park it on a level surface, leave the engine running, transmission in park, and then check the fluid level. Then go by what the level is.

The "guy at Jiffy Lube" is only slightly more knowledgeable about how your truck works than the person manning the drive-thru at McD's. It might even be their second job.

Raptordude · July 16, 2016

Yeah drive around, get it hot, let it idle on a level surface, then click it through every gear starting in park then ending in park....then check it while the motor is running. I believe that the amount to take it from the bottom dot on the dipstick to the top is only HALF a quart. Not sure that is true with the Silverado though....so keep that in mind.

I would check it a few times before you take any out just to make sure you're getting an accurate reading

If it is over full, I'd take some out. Just don't take out too much

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