some 4wd 4l80e swap info
Nov 7, 2003 | 10:15 PM
#1
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single digit dreamer
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From: omaha ne
some 4wd 4l80e swap info
i know most of you guys are 2wd so this info will be of limited use to you but for the 4wd guys it will be helpfull.
the tranny itself is about 4" longer
the adapter that goes from the tranny to the transfer case is shorter on the 4l80e set up so that gets the transfer case closer than 4" off, it ends up being more like 1 1/2" farther back. just enuff that the drive shafts will probably need the lengths changed.
the tranny mount is on that adapter, it ends up about 3" farther back than the 4l60e set up. the way the old cross member is set up it looks like i can easily weld a plate on the back with a couple of gussets and mount the tranny to that.
now on to the transfer case. got some good news and some bad. first the bad, the output shaft is larger on the 4l80e so the 1500 transfer case wont work. now the good, both the front and rear driveshafts use the same yolks on the HD transfer case as the 1500 transfer case so i can use my original driveshafts, just have to have the length adjusted.
cant say for sure on the exhaust but it looks like the factory y pipe will fit easily too. the y croses over in front of the cross member and the cross member wont be moving, just a plate added behind it. the 4l80e pan is super shallow especialy in the rear so i think the cross over part will be fine.
prety sure the guy that sold me this motor lied to me too, i will shoot some pics later, the intake ports on my 50k 4.8 are prety clean, the ports on the suposed 50k 6.0 are completly filthy, like oily and completly covered, lots of dirt under the intake, paint completly worn off the wp pully, paint looks good on the 4.8 water pump. he also didn't send me a mass air sensor like he said he would. if it has a few more miles that is ok but i hope it isn't complety worn out, i would like to beat on it for awhile before i have to build it. also told me it was an electric shift transfer case when it is really a manual shift unit. some people are ********.
the tranny itself is about 4" longer
the adapter that goes from the tranny to the transfer case is shorter on the 4l80e set up so that gets the transfer case closer than 4" off, it ends up being more like 1 1/2" farther back. just enuff that the drive shafts will probably need the lengths changed.
the tranny mount is on that adapter, it ends up about 3" farther back than the 4l60e set up. the way the old cross member is set up it looks like i can easily weld a plate on the back with a couple of gussets and mount the tranny to that.
now on to the transfer case. got some good news and some bad. first the bad, the output shaft is larger on the 4l80e so the 1500 transfer case wont work. now the good, both the front and rear driveshafts use the same yolks on the HD transfer case as the 1500 transfer case so i can use my original driveshafts, just have to have the length adjusted.
cant say for sure on the exhaust but it looks like the factory y pipe will fit easily too. the y croses over in front of the cross member and the cross member wont be moving, just a plate added behind it. the 4l80e pan is super shallow especialy in the rear so i think the cross over part will be fine.
prety sure the guy that sold me this motor lied to me too, i will shoot some pics later, the intake ports on my 50k 4.8 are prety clean, the ports on the suposed 50k 6.0 are completly filthy, like oily and completly covered, lots of dirt under the intake, paint completly worn off the wp pully, paint looks good on the 4.8 water pump. he also didn't send me a mass air sensor like he said he would. if it has a few more miles that is ok but i hope it isn't complety worn out, i would like to beat on it for awhile before i have to build it. also told me it was an electric shift transfer case when it is really a manual shift unit. some people are ********.
Nov 7, 2003 | 11:21 PM
#3
Good info on the transmission. You have the electronics figured out yet for it?
I've been curious, but did the nitrous backfire break the MAF wires? I assume so since they look really delicate.
I've been curious, but did the nitrous backfire break the MAF wires? I assume so since they look really delicate.
Nov 7, 2003 | 11:37 PM
#4
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From: omaha ne
Originally Posted by BigTex
Good info on the transmission. You have the electronics figured out yet for it?
I've been curious, but did the nitrous backfire break the MAF wires? I assume so since they look really delicate.
I've been curious, but did the nitrous backfire break the MAF wires? I assume so since they look really delicate.
i think i have the electronics figured out, going with the 4.8ecm reprogramed by speartech just for the tranny, i got the tranny harnes from them all ready, it is just 2 wires to the ecm and a plug adapter.
i am not too bumed about the transfer case, going with the HD one rated at more than twice the torque of the autotrack unit can't be all bad. right now i think i will try just puting the lever in 4 hi and let the front diferential control the lock up. if that causes problems i will have to try and get a lever and linkage.
Nov 8, 2003 | 01:19 PM
#5
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GM has an AutoTrac case that fits the 4L80E that comes in the 2500HD trucks. It came out in '03 I believe. It is the NP8 case according to the site.
I don't think I'd buy one new unless you know the parts person at the dealer well...but that may be your only choice.
I don't think I'd buy one new unless you know the parts person at the dealer well...but that may be your only choice.
Nov 8, 2003 | 01:38 PM
#6
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single digit dreamer
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From: omaha ne
they have offered that autotrack case with the non HD2500 since 99, i could find one used it i really wanted to keep it working like stock but i will just go with the HD case, it is rated at 5500ft/lb's the autotrack is rated at 2200ft/lbs. when i am making 1000ft/lbs at the motor times 2.75 1st gear plus a 2.7STR and 4 wide drag radials i might just need that case 
can ya say whiplash 
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Nov 9, 2003 | 12:27 AM
#8
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single digit dreamer
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From: omaha ne
a little more info.
the flex plate is significantly diferent for the 2 trannys, the 4l60e one is only punched for 3 bolts, it has more material removed and is bulged out in the middle.
the flex plate is significantly diferent for the 2 trannys, the 4l60e one is only punched for 3 bolts, it has more material removed and is bulged out in the middle.
