4l80e swap thread... Again...

[df2x4]

I just replied to your PM but I hadn't seen your most recent post yet so I'll add some stuff here.

Regarding transmission coolers, you say you've already ordered something but the TruCool M7B is pretty much a direct fit with some minor trimming of the factory AUX cooler brackets and some fitting adapters. More info here, the TruCool M7B is the exact same product as the B&M coolers mentioned here in a different box with a lower price. Both are manufactured by Long, they're identical.

https://www.gmt400.com/threads/how-to-factory-auxiliary-trans-cooler-upgrade.18104/

Stock driveshafts from a K2500 4L80E truck might work for you. Mine was a 2WD but my mechanic ended up finding a two piece driveshaft from a 4L80E equipped C2500/3500 that worked for me.

Regarding the harness adapters, I don't think year/vehicle spec really matters that much as long as you get one for a '94+ swap. I don't think anything changed at the transmission connector for quite a while after that. As long as the kit you ordered comes with a long enough input speed sensor pigtail to reach your PCM you should be good.

Speaking of which, do you know which two pins at your PCM you'll need to connect the input speed sensor to? If not you may want to track down a factory service manual for an '01 Express or ask somebody who has one.

 

[Supercharged111]

I need to visit your all's junkyards as the ones here in Vegas suck - no 4L80Es to be found...folks are paying over $500 for a rebuildable core (not a known, good unit).

I recently picked up a used supposedly good 130k 4L80 with NP243 for the grand total of 500 smackers. Looks the part. Trans is going into my dually in October, we'll find out then if it's junk or not. Stuff is a little scarce here in CO too. Out east stuff in general is cheaper and more abundant. It's gotta be an out west thing. You'll have a big town and then just a bunch of nothing for 100 miles or more. Out east even when you're in the middle of nowhere there's still houses pretty much the whole way and you really don't have to be that careful planning fuel stops either.

As for this thread? Another vote for the mighty 4L80 swap. A couple notes though:

Wiring harness doesn't need swapped, I soldered 18ga speaker wire to a VSS pigtail and pinned that into the 411 with some leftover pins from the swap. All crap I had on hand.

I can't say I agree with your assertion that the 80 eats 10-15% more hp. Seat of the pants, the difference felt more related to the gearing and added moment of inertia from the larger, heavier torque converter. Truck pulled noticeably harder in 4th after the swap where RPMs aren't changing quickly.

 

[NickTransmissions]

I recently picked up a used supposedly good 130k 4L80 with NP243 for the grand total of 500 smackers. Looks the part. Trans is going into my dually in October, we'll find out then if it's junk or not. Stuff is a little scarce here in CO too. Out east stuff in general is cheaper and more abundant. It's gotta be an out west thing. You'll have a big town and then just a bunch of nothing for 100 miles or more. Out east even when you're in the middle of nowhere there's still houses pretty much the whole way and you really don't have to be that careful planning fuel stops either.

As for this thread? Another vote for the mighty 4L80 swap. A couple notes though:

Wiring harness doesn't need swapped, I soldered 18ga speaker wire to a VSS pigtail and pinned that into the 411 with some leftover pins from the swap. All crap I had on hand.

I can't say I agree with your assertion that the 80 eats 10-15% more hp. Seat of the pants, the difference felt more related to the gearing and added moment of inertia from the larger, heavier torque converter. Truck pulled noticeably harder in 4th after the swap where RPMs aren't changing quickly.

That's a good deal, if the transmission is actually working...We're paying between $300-400 for later model 4L80E cores that are known to be bad.

Most folks swap the harness, but if you can make it work w/improvisation, more power to ya.
HP consumption differences don't really matter as long as you're happy with the result. That's the only thing that counts so good on you for doing the swap.

If you haven't already, take the pan off of your recently acquired 4L80E that's going into your dually, replace the filter and handle the shift solenoids - many of them literally come apart once you start handling them. Replace if need be. Same with the harness - look for areas of cracked insulation or exposed wire. I've mentioned this in other posts and will do so here as well in that I'd replace the wiring harness. They will sometimes leak through the connector and in some cases, put the transmission into limp mode. Install a shift kit or like-kind mods if you feel comfortable doing so...Replace the boost valve w/a Sonnax 4L80-LB1 kit for a bit more line pressure to your clutch packs.

 

[Supercharged111]

That's a good deal, if the transmission is actually working...We're paying between $300-400 for later model 4L80E cores that are known to be bad.

Most folks swap the harness, but if you can make it work w/improvisation, more power to ya.
HP consumption differences don't really matter as long as you're happy with the result. That's the only thing that counts so good on you for doing the swap.

If you haven't already, take the pan off of your recently acquired 4L80E that's going into your dually, replace the filter and handle the shift solenoids - many of them literally come apart once you start handling them. Replace if need be. Same with the harness - look for areas of cracked insulation or exposed wire. I've mentioned this in other posts and will do so here as well in that I'd replace the wiring harness. They will sometimes leak through the connector and in some cases, put the transmission into limp mode. Install a shift kit or like-kind mods if you feel comfortable doing so...Replace the boost valve w/a Sonnax 4L80-LB1 kit for a bit more line pressure to your clutch packs.

Pan is coming off for sure, make sure there isn't a bunch of trash sitting in the bottom. Luckily it's been sitting with the dipstick and tube in it so hopefully it's decent in there. I think I'll just try and run it as is. What I really want to do is run it long enough to rebuild and beef up the one in the dually and swap them back out so there's a known good spare on the shelf and a fresh, stout build in the dually.

 

[Astro]

Pan is coming off for sure, make sure there isn't a bunch of trash sitting in the bottom. Luckily it's been sitting with the dipstick and tube in it so hopefully it's decent in there. I think I'll just try and run it as is. What I really want to do is run it long enough to rebuild and beef up the one in the dually and swap them back out so there's a known good spare on the shelf and a fresh, stout build in the dually.

Sup, which pins are you using on the 0411?

Nick, thanks again for the tips. I'm going to drop the pan as well. Idk how they ship these for one. Do they drain them? Leave the fluid in there? Idk.

I checked the chassis today and didn't find any holes for an easy crossmember relocation so it looks like I'll have to drill them. Not hard, but annoying nevertheless.

Df thanks for the tips! I ended up getting this one because the reviews are good and it's huge lol.
SINTLY LPD47391 Plus Engine Transmission Oil Cooler Kit https://a.co/d/cyinPlx

Hopefully it works out.

This is going to be fun lol

 

[NickTransmissions]

Pan is coming off for sure, make sure there isn't a bunch of trash sitting in the bottom. Luckily it's been sitting with the dipstick and tube in it so hopefully it's decent in there. I think I'll just try and run it as is. What I really want to do is run it long enough to rebuild and beef up the one in the dually and swap them back out so there's a known good spare on the shelf and a fresh, stout build in the dually.

Sounds like a good plan...let me know if you have any questions once you decide to embark on the rebuild...I'll also be posting a '4L80E Information' thread similar to what I've posted for the 4L60E some time in the next couple weeks...Will have tons of parts, interchange and tips/tricks information. Plus there's 10-12 4L80E vids on my channel, all of which are oriented towards high performance so good reference material there also.

 

[Supercharged111]

Sounds like a good plan...let me know if you have any questions once you decide to embark on the rebuild...I'll also be posting a '4L80E Information' thread similar to what I've posted for the 4L60E some time in the next couple weeks...Will have tons of parts, interchange and tips/tricks information. Plus there's 10-12 4L80E vids on my channel, all of which are oriented towards high performance so good reference material there also.

Now that I know you have a channel, I see that now. The only one I've rebuilt was back in 2014 with adult supervision and a lot of that is buried deep in my crappy memory. I think your vids plus the ATSG manual should make this next build a success. I've done a few T56s, but would really like to get better at these autos.

 

[Road Trip]

If you haven't already, take the pan off of your recently acquired 4L80E that's going into your dually, replace the filter and handle the shift solenoids - many of them literally come apart once you start handling them. Replace if need be. Same with the harness - look for areas of cracked insulation or exposed wire.

Hi Nick,

Not to hijack the thread, but I'm getting ready to do some preventive maintenance on
my 4L80-E that is currently working fine, but had accumulated 219K miles on it prior
to my purchase. Q: Do you have a personal transmission filter brand preference, or do I
just press with the AC/Delco bits? (ie: If there's a demonstrably superior filter I have no
issue spending the difference.)

I'll also be posting a '4L80E Information' thread similar to what I've posted for the 4L60E some time in the next couple weeks...Will have tons of parts, interchange and tips/tricks information. Plus there's 10-12 4L80E vids on my channel, all of which are oriented towards high performance so good reference material there also.

I'm looking forward to this. Like @Supercharged111 , I am comfortable
rebuilding manual transmissions, but I am interested in adding the
auto trans refresh skillset. (My motivation is pure, for I'm seriously
considering refreshing/improving the 454 in my '99 C2500 to the point
where rebuilding the existing 4L80-E and field upgrading it to comfortably
handle the additional torque produced would make me a very happy camper.)

Thanks!

 

[NickTransmissions]

That's awesome you guys rebuild manual transmissions! I have two T56 transmissions, one good and another with a 5/6 cluster and mainshaft that ill be rebuilding in the fall or early spring.

Automatics are different but no more or less difficult. Each has aspects that have require focus/awareness but nothing you wont be able to handle.

Fluid-wise any Dex-Merc or Dex6 brand will work. A few of my customers like Red Line for their street strip cars...Some folks use Type F in performance builds as it's said to provide firmer shifts, everything else equal.

 

[Astro]

I think I could definitely perform a refresh with the tools I have now and even install a shift kit. The main thing I'm wondering about at this moment is what the best way to fill the tranny with fluid is. I've done many pan drops and filter changes, but not an entire fluid change.

I'm kinda stoked they're sending it dry as it'll let me put some really good fluid in there to begin with.

Nick, do you have videos on the 80 that cover a simple refresh? Also, which channel are you talking about? on you tube or something?