CitrusTheDragon

I am going to be doing a 6L90 swap and I was wondering will need to be change and what to grab off the donor truck.

mrvedit

Search for the "6L80E" threads here; this is a very complex swap due to its electronic controls and sheer size.
What are you swapping it into?

CitrusTheDragon

04 Ascender(trailblazer) currently a 5.3L 4L60e but it leaks so I was going to upgrade to an lq4/9 with a 6speed. Might listen to suggestions for an easier swap. I'm just trying to get better mpg.

mrvedit

I don't have personal experience, but from reading many trans thread here...
Your '04 PCM will not control a 6L80E; you would therefore need a special controller which costs $800. You would need to mod the trans mounting and get a shorter drive shaft. This assumes the large 6L80E even fits in your tunnel. Its extra 100 lb weight will not help your gas mileage. Also its 6th gear ratio (0.65) is not significantly taller than a 4L60E (0.70) and therefore unlikely to give you better gas mileage.
Just my opinion.

Alex Quick

I put a 2011 6.0 litre with a 6L80 into a 41 Chev. It was quite expensive. The 6L90 has a huge output shaft and yoke. You need a motor that has a 58 tooth reluctor and a PCM that runs a 6L80 or 6L90. I paid $2500 for the motor, $1700 for the trans, and $2000 to have Speartech provide a tuned PCM, a wiring harness, and to retune the trans module. Speartech did a great job, everything runs well. For the same cost you could use a 4L80 with a Gearvendors overdrive.

mrvedit

Wow. If you ever have the time to start a thread documenting all this, that would be much appreciated. There is very little 6L80E swap info available on this forum.

zgp

Agreed there is very little info on these types swaps. That should change in the near future. I have done quite a few of them, more to come.