benjaminforeal

Im currently trying to find a way to make my dealer investigate more than the saying "yeah we heard of the issue and there is nothing we can do". BULLS*$& lol. I'm not settling for that statement. I want my truck fixed and fixed right.

Dang thank god I'm under full warranty still. Truck is going in this Thursday. Thanks for the input.

I just started to notice a shutter on my truck driving it the other day. about 15,500 miles and just noticed it. 6.2 8 spd. i've have my truck in for a transmission software update and relearn for the harsh clunking when cold going in to drive or reverse. This helped quite a bit and I was pretty happy with the truck up until now. I will be cruising down the highway, no load, cruise set at 70 - and I can watch the rpms fluctuate about 100 rpms or so. Every time the tach needle rises a tad (consistently every 3 seconds or so) there is a crazy shutter (steering wheel and dash vibrates). Sounds like torque converter from what I've read so far in this thread?

It was a software update, unfortunately I don't know what the update was. I'm sure on the new trucks GM is putting out they will have the new software installed is my assumption.

I have the 8 speed

Just had my transmission updated with the new program. No more clunking after the truck sits overnight when shifting in to drive or reverse.... for now.

Thank you so much for this! Taking in my truck next week to have it serviced for this issue. It has been driving me nuts ever since I bought the truck last year.

Little update on mine: front air dam removed, 2.5" level installed in front, running boards, window tint, muffler swap.

92 mph cut off!? Dang.. I found out mine was limited at 99 mph on the interstate last weekend. I'm surprised to hear the Sierra would have different cut-off.

Awesome, that would be great. What kind of mods done to the one you have tuned? I'm wanting to do full bolt-on's eventually. Might was well do E-85 conversion/tune at the same time with bolt ons. Would have to get a tune for 91 as well since E-85 isn't available conveniently close to me where I'm at. Would just run E-85 at the track probably. The E-85 in my area over this last summer was measuring around 70. I can't imagine what the winter blend is testing out.

Have you tuned a L86 on e85 yet? Really curious to see some results of someone converting their new 6.2 to E85. I would love to convert over someday.