LQ9 6.0 into a 2001 Yukon XL - a couple questions

I found a LQ9 6.0 with full harness, computer and all accessories. A few questions... I have heard there is a spacer plate used for 4L80 transmissions. I am attaching it to a 4L60 so what am I looking out for there? Will I need anything special to attach it to the torque converter, transmission? Also, since I have the original computer, I assume that it will not need a tune? and I am also worried about replacing the harness; do I have to run the harness through the firewall for the dash stuff? I have read the other posts but these questions were not mentioned from what I found.

Yes, the 4L80e bolted to an LS engine did have a spacer, but that transmission only came in the 8 lug trucks.

The LQ9 was used in the 1500 trucks, so it got the 4L60e-family of transmissions, which means that it will bolt up to your transmission. So no issues on that.

It depends on what year your 6.0 engine came from. There were differences throughout the production runs.

It may be better to keep your ECU and wiring harness, and just get the 6.0 engine reflashed. Some little things may also require swapping such as the oil pressure sender (1 wire vs 3 wire). Again, it depends on what year the 2 engines are...

InterceptorF said:

I found a LQ9 6.0 with full harness, computer and all accessories. A few questions... I have heard there is a spacer plate used for 4L80 transmissions. I am attaching it to a 4L60 so what am I looking out for there? Will I need anything special to attach it to the torque converter, transmission? Also, since I have the original computer, I assume that it will not need a tune? and I am also worried about replacing the harness; do I have to run the harness through the firewall for the dash stuff? I have read the other posts but these questions were not mentioned from what I found.

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I beleive the flex plate may need to be changed (4L80e to 4L60e). What year is the LQ9 and extras? There was a change in 2003 that may make your (2001) dash incompatible. Also drive by cable vs drive by wire (2003+). I have a 2002 and want to do just the engine swap with accessories and DBC TBI, due to dash and DBC, and get a tune after for simplicity. Existing harness should be plug and play. I'll defer to the experts, so I'll be watching this thread!

The easiest way to do this is to take the flex plate and intake manifold off the LQ9. Remove your engine and drop this one in using those parts from your old engine. The LQ9 will bolt right up to a 4L60E, just make sure to use the 5.3 flexplate and the torque converter will have no issues either. Use your old harness, sensors, etc. I just did a 5.3 to LQ9 swap in a Silverado a month ago.
What vehicle did the LQ9 come out of? You may need a tune anyway......... you really would probably want one regardless.

justirv said:

I beleive the flex plate may need to be changed (4L80e to 4L60e). What year is the LQ9 and extras? There was a change in 2003 that may make your (2001) dash incompatible. Also drive by cable vs drive by wire (2003+). I have a 2002 and want to do just the engine swap with accessories and DBC TBI, due to dash and DBC, and get a tune after for simplicity. Existing harness should be plug and play. I'll defer to the experts, so I'll be watching this thread!

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Did this exact swap in my '01 Burb LT 4wd. Installed a fresh built LQ9.
Remove the spacer on the back of the crankshaft and use the 5.3L flex plate, (just install everything as the 5.3 comes out). Then have the PCM reprogrammed with the new engine displacement, (gave it a very mild adjust to the tune), and wal la. 3 years and 60,000 miles later still LOVEN IT! When I get in my wifes bone stock '01 Burb LT 4wd, (identical rigs, hers is green, mine is white, lifted, and slightly larger tires), hers feels SOOO much slower!