2008 Yukon Engine and 4L80e upgrade questions
03-11-2017, 09:07 PM
#1
Registered User
Thread Starter
Join Date: Mar 2017
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
2008 Yukon Engine and 4L80e upgrade questions
Hey all! I've been posting over at the Tahoe/Yukon forums, but never seem to get any replies to my questions. So whilst searching tonight, I found this forum and am hoping to get some guidance.
I have a 2008 Yukon SLT that originally came with a 5.3 and 4L60 transmission. Since I had a few exhaust manifold bolts that had broken off, I was originally going to pull the heads to fix them and do a slight refresh on my motor. However, a friend of mine was scrapping his 2000 Silverado 2500 and offered me his LQ4 block and 4L80e transmission. So, long story short, we have fully rebuilt the motor, added LS3 heads, installed an upgraded custom cam, had the pistons bored 30 over, the crankshaft turned, and everything balanced. All of the parts on this are 100% new now, and we are in the process of installing it. I am on a time constraint and have to try to get it finished by the end of this coming week.
Once my replacement motor mount arrives tomorrow, we'll have the engine put back into the truck, and then I have to switch gears (Pun intended!) and get the tranny and transfer case installed. Here is where I need some help. I have tried searching, and haven't found everything that I need to know. I do know that the 4L80 will bolt right back up to its original motor, and I know that I have to move the crossmember back to mount it. I also ordered and have the wire harness adapter for the swap, and a custom tune has been written for me to reflash with my hptuner. Here are my questions that I need help with.
Driveshafts - I measured the transmissions and the 4L80 looks to be 1 1/2 - 2 inches longer. Because of this, I know the front driveshaft needs to be longer and the rear driveshaft is shorter. Would the front driveshaft from the Silverado be useable? And for the rear, if I go to a local junkyard, is there a vehicle I can look for that would just fit, or am I better off having my stock one cut down to size? And if I'm having it cut, do I use the steel one from my truck or the larger aluminum one from the Silverado?
Frame Mount - The current mount would be difficult to reuse and move. Is there a good way to use that, or would it be easier to use the frame mount from the Silverado and drill all new mounting holes?
Transmission to T-Case - Will the transfer case mate to the 4L80 transmission as is? It is not an AWD model. I read somewhere about possible different spline counts. If it won't mate right up, what needs to be done?
I'm sure I'm forgetting something, but that is all I can think of at the moment. I appreaciate any help/guidance you guys can give. Thanks for reading!
I have a 2008 Yukon SLT that originally came with a 5.3 and 4L60 transmission. Since I had a few exhaust manifold bolts that had broken off, I was originally going to pull the heads to fix them and do a slight refresh on my motor. However, a friend of mine was scrapping his 2000 Silverado 2500 and offered me his LQ4 block and 4L80e transmission. So, long story short, we have fully rebuilt the motor, added LS3 heads, installed an upgraded custom cam, had the pistons bored 30 over, the crankshaft turned, and everything balanced. All of the parts on this are 100% new now, and we are in the process of installing it. I am on a time constraint and have to try to get it finished by the end of this coming week.
Once my replacement motor mount arrives tomorrow, we'll have the engine put back into the truck, and then I have to switch gears (Pun intended!) and get the tranny and transfer case installed. Here is where I need some help. I have tried searching, and haven't found everything that I need to know. I do know that the 4L80 will bolt right back up to its original motor, and I know that I have to move the crossmember back to mount it. I also ordered and have the wire harness adapter for the swap, and a custom tune has been written for me to reflash with my hptuner. Here are my questions that I need help with.
Driveshafts - I measured the transmissions and the 4L80 looks to be 1 1/2 - 2 inches longer. Because of this, I know the front driveshaft needs to be longer and the rear driveshaft is shorter. Would the front driveshaft from the Silverado be useable? And for the rear, if I go to a local junkyard, is there a vehicle I can look for that would just fit, or am I better off having my stock one cut down to size? And if I'm having it cut, do I use the steel one from my truck or the larger aluminum one from the Silverado?
Frame Mount - The current mount would be difficult to reuse and move. Is there a good way to use that, or would it be easier to use the frame mount from the Silverado and drill all new mounting holes?
Transmission to T-Case - Will the transfer case mate to the 4L80 transmission as is? It is not an AWD model. I read somewhere about possible different spline counts. If it won't mate right up, what needs to be done?
I'm sure I'm forgetting something, but that is all I can think of at the moment. I appreaciate any help/guidance you guys can give. Thanks for reading!
