LB7: 5 speed to 6 speed
- Thread starter 20chevy04
- Start date
I never ran it with 3.73's, so no real benchmark there. I have gotten as high as 17-18 driving strictly in town, but haven't gotten that in awhile. My current tune is WAY to much fun, and it sounds WAY to good to baby it all the time. Plus my son gets a HUGE smile on his face when I get on it. And yes, you get funny looks when you blow somebodys doors off, and they look over and see the carseat.
So then basically no difference in opinions than 5 years ago. Price has gone up on the kit like $400 and this swap is still questionable. My 2005 has right around 35,000 miles on it and I was thinking that since it's still "new" that the 6 sp would pay for itself during my life time. Just can't see buying a new truck for the green they want to gain an extra gear. sure there's more items on the new one than that but hard to justify going into debt on a new truck again. I know I'll return to the US some year, maybe if I drove my truck more then a new one would have more appeal.
So other than cost and marginal gains, are there negative aspects of doing this in regards to reliability?
So other than cost and marginal gains, are there negative aspects of doing this in regards to reliability?
So this might have neen asked before but not finding much info on it. I dont need complete part by part but how different is the 5spd vs 6spd internal wise. I know the valve body wiring harness and nsbu are different. But how much else is different? Just wondering, no real rhyme or reason other than i would like to know.
Thanks Mike! I have been hearing people say they are drastically different and not even close to the same. I have never pulled an Allison apart but from what i have read they don't sound like they are drastically different.
No. I believe the cooler fittings are different between the LB7 5-speed and the 6-speed, but otherwise it is (mechanically) bolt in.
In order for a 2006+ Allison to work right in a LB7 with the LB7 ECM and TCM, you would need to swap in the 5-speed valve body, internal harness, NSBU and cooler fittings. You would also need to be sure to get an earlier one that has a bung in the bellhousing for a speed sensor. Of course, it will only work as a 5-speed.
To get it to work in a 03-05 (or pre-03, but that is far more involved) truck as a 6-speed, you would need to convert to all LBZ electronics (ECM, TCM, GPCM, Cluster, Throttle pedal) and top end at minumum.
That's 'converting to a stock 6-speed' in a nutshell...