spiGini

Just an update since nobody responded. Little more information on my issue which starts when the trans temp reaches above 150 degrees. Below 150 degrees the transmission has no issues shifting into 4th or 4th gear lock up. Above 150 degrees it will not shift into 4th but has no issues shifting 1-3. My thought was the fluid was getting thinner but didn't know what or where it was going wrong. Dropped the pan and checked all of the solenoids and everything was in spec for ohms reading. Thought it could be the feed limit actuator that is known to bore itself out (still unsure if that is damaged but ordered a whole new valve body with upgraded transgo feed limit). So in preparation for the new valve body to arrive I decided to take out the old one last night. When I dropped the valve body along with it came half of the 4th bolt or 4th clutch bolt. The other half was stuck in the transmission. I assume it was over torqued at one point causing it to crack and when the fluid gets thin it escapes through the threads instead of providing constant pressure to the 4th piston. Had to use a tap and screw to get out the half stuck in the transmission. Now not sure if this is the exact thing causing the issue but I assume it will be. So a $5 part was causing me to lose 4th gear when the transmission reached over 150 degrees. Just wanted to update the thread in case anybody has issues later on and doesn't know where to start. If everything checks out with the solenoids i'd take a look at this bolt. And I'll update this weekend after I put in the updated valve body and new 4th bolt in to verify everything is good to go now

First post here in a long time but just recently picked up a 2005 GMC 2500HD 6.0 with 183k miles and 4l80e transmission. Vehicle is really clean but have come up with a transmission issue. When cold the transmission shifts into OD on the highway no issues. When the transmission gets up to operating temp it will not shift into OD, it sits at 3k rpm at 70mph. I did a stall speed test and it comes up to 2400rpm (believe stock is 2600) unsure if that is a real issue only 200rpm difference so don't believe it is the TC. When cold or warm the transmission shifts smooth as anything just when warm will hang 3rd. Checked fluid and it looks clean, not burned and full. Wondering if its worth changing the fluid/filter/shift solenoids and go from that point or just bring it to a shop. Not sure if the wrong fluid was used and if that would even cause the shifting issue when warm or if it is just the TC that needs to be replaced. Thanks!

Ive had my 2.5"RC lift for about 2500 miles now on 33s. No issues with the steering. Dont know why or how it would mess with it at all.

What tire/wheel setup went with that? And definitely show some pics

I'll double check tomorrow and let you know but i'm sure you will have no problem

I just put on my 275/70/18 with my RC 2.5" Lift this morning and wish I went with at least a 295.. you will have plenty of room.

So glad you posted this! Was gonna go with the same lift, wheel and tire setup but -12 offset. Wasnt to sure the tires would look good but it def does. My mind is made up now!

I hollowed mine out but only the center, didn't take it all out of the sides. Wonder if I should go back and take it all out if its creating a disruption in the air flow through the partial hollowed portion.

i would prob say VHT Night Shade

I searched this thread as well as the forum and not going to lie did not want to read through 25 pages of posts as I just joined the forums. Have the 4.3l v6 and was wondering if any tuning options have come out or will be coming out?