sspowr Posted September 3, 2013 Report Share Posted September 3, 2013 Got a 2003 Silverado SS (6.0L gas). The 4L65E in it is shot. So I figure this is a good opportunity to upgrade it to a 6-speed automatic. It's an AWD truck and I'd like to keep it that way. So what are the good 6sp auto trannies out there? Thanks! Quote Link to comment Share on other sites More sharing options...
diggerdan11 Posted September 3, 2013 Report Share Posted September 3, 2013 I know its possible but its going to be expensive and a major pain in the butt. You might be better off just replacing it with another 4l60 or maybe a 4l80e. Quote Link to comment Share on other sites More sharing options...
1BAD2K Posted September 3, 2013 Report Share Posted September 3, 2013 Yeah from what I've read you'll need to adapt and run a dedicated tcm. I last checked with a guy who was building an adapter to run the 149 awd transfer case and he wanted somewhere in the $1, 300 range. That's just to be able to bolt your t case to one of the newer 6 speed trans. You are probably in the $6, 000 to do this conversion, if not more. I would suggest a 4l80e upgrade. Quote Link to comment Share on other sites More sharing options...
chawkins6789 Posted September 3, 2013 Report Share Posted September 3, 2013 Isn't there a 6L90E in AWD form for the Denali? Quote Link to comment Share on other sites More sharing options...
f1ss Posted September 3, 2013 Report Share Posted September 3, 2013 (edited) I drove a HD Diesel with the 6 speed and absolutely would never go with that transmission. It would keep shifting gears as if it could not make its mind up which gear to stay in. Contractor on my house let me drive it, then he traded it in for an older HD with the 4 speed. Just my opinion, it could have been my driving habit, who knows. Edited September 20, 2013 by 03mass (see edit history) Quote Link to comment Share on other sites More sharing options...
1BAD2K Posted September 3, 2013 Report Share Posted September 3, 2013 Isn't there a 6L90E in AWD form for the Denali? Yes, but it isn't viscous coupled like the ss t case is (149). The ss case is more performance oriented. The 6 speed awds, use electronics in the t case that tell the truck apply brake on the wheels that start to spin. Quote Link to comment Share on other sites More sharing options...
battousai Posted September 4, 2013 Report Share Posted September 4, 2013 I drove a HD Diesel with the 6 speed and absolutely would never go with that transmission. It would not keep shifting gears as if it could not make its mind up which gear to stay in. Contractor on my house let me drive it, then he traded it in for an older HD with the 4 speed. Just my opinion, it could have been my driving habit, who knows. If its a Durramax, its the allison behind it, not a 6Lxx totally different. Quote Link to comment Share on other sites More sharing options...
sspowr Posted September 4, 2013 Author Report Share Posted September 4, 2013 I have no issues with the Allison in my worktruck... Anyway, I posted another thread about my tranny issues, and will suspect talking about swapping it until I have more info from the other thread: http://www.silveradoss.com/forums/topic/83156-tranny-issues-anyone-have-any-ideas/ Quote Link to comment Share on other sites More sharing options...
onebadmax Posted September 19, 2013 Report Share Posted September 19, 2013 I drove a HD Diesel with the 6 speed and absolutely would never go with that transmission. It would not keep shifting gears as if it could not make its mind up which gear to stay in. Contractor on my house let me drive it, then he traded it in for an older HD with the 4 speed. Just my opinion, it could have been my driving habit, who knows. SMH.... Quote Link to comment Share on other sites More sharing options...
f1ss Posted September 20, 2013 Report Share Posted September 20, 2013 whats SMH? Quote Link to comment Share on other sites More sharing options...
f1ss Posted September 20, 2013 Report Share Posted September 20, 2013 (edited) If its a Durramax, its the allison behind it, not a 6Lxx totally different. I must be confused, thank you for the correction sir. After seeing him in a Diesel for 6 months I thought the new 08+ HD Diesels came with an Allison 6spd (my error). When he got his new HD 08 he hated the 6spd (so it must have been gasoline) and traded it back in the same week he bought the 08 and went back to the 06 HD Diesel. I test drove all 3 trucks as he wanted to take my truck for a spin. My bad, but thank you for the kind correction sir. Edited September 20, 2013 by 03mass (see edit history) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.