4l60e change in shift firmness
03-13-2018, 09:01 PM
#1
TECH Enthusiast
Thread Starter
4l60e change in shift firmness
I have a 2008 GMC Sierra 5.3 with 4l60e. At 80,000 miles the AFM went out and I installed a BTR truck stage 2 cam, AFM delete and Jon Weeks tune. Around 110,000 miles my wife wanted to get an 18 foot camper to watch the solar eclipse in Tennessee, so I installed the sonnax sure cure ( shift kit ) 2nd gear and 4th gear serves pluse a B&M trans cooler. The trans shifted great, Jon Weeks upped the line pressure, quickened the shifts and removed torque management during the cam install and the trans shifted great! it had a firm shift into overdrive, the heavy duty 2-3 was a great addition and I removed the PWM from the converter.
It was all awesome till 139,000 ish miles and the shifts started to feel stock again all of a sudden I contacted Sonnax and the tech suggested I check the line pressure in the trans at several points. I have not done this yet, called earlier today, but am wondering if anyone else has had a similar experience. The fluid looks the same as when it was changed around 80,000 and smells normal.
Anybody have any ideas what may have happened? besides being a full time college student for Mechanical Engineering, I work 72 hours a week as a federal fire fighter and would like to limit any down time for my daily driver.
Thanks! Art
It was all awesome till 139,000 ish miles and the shifts started to feel stock again all of a sudden I contacted Sonnax and the tech suggested I check the line pressure in the trans at several points. I have not done this yet, called earlier today, but am wondering if anyone else has had a similar experience. The fluid looks the same as when it was changed around 80,000 and smells normal.
Anybody have any ideas what may have happened? besides being a full time college student for Mechanical Engineering, I work 72 hours a week as a federal fire fighter and would like to limit any down time for my daily driver.
Thanks! Art
03-14-2018, 11:57 AM
#2
I have a 2008 GMC Sierra 5.3 with 4l60e. At 80,000 miles the AFM went out and I installed a BTR truck stage 2 cam, AFM delete and Jon Weeks tune. Around 110,000 miles my wife wanted to get an 18 foot camper to watch the solar eclipse in Tennessee, so I installed the sonnax sure cure ( shift kit ) 2nd gear and 4th gear serves pluse a B&M trans cooler. The trans shifted great, Jon Weeks upped the line pressure, quickened the shifts and removed torque management during the cam install and the trans shifted great! it had a firm shift into overdrive, the heavy duty 2-3 was a great addition and I removed the PWM from the converter.
It was all awesome till 139,000 ish miles and the shifts started to feel stock again all of a sudden I contacted Sonnax and the tech suggested I check the line pressure in the trans at several points. I have not done this yet, called earlier today, but am wondering if anyone else has had a similar experience. The fluid looks the same as when it was changed around 80,000 and smells normal.
Anybody have any ideas what may have happened? besides being a full time college student for Mechanical Engineering, I work 72 hours a week as a federal fire fighter and would like to limit any down time for my daily driver.
Thanks! Art
It was all awesome till 139,000 ish miles and the shifts started to feel stock again all of a sudden I contacted Sonnax and the tech suggested I check the line pressure in the trans at several points. I have not done this yet, called earlier today, but am wondering if anyone else has had a similar experience. The fluid looks the same as when it was changed around 80,000 and smells normal.
Anybody have any ideas what may have happened? besides being a full time college student for Mechanical Engineering, I work 72 hours a week as a federal fire fighter and would like to limit any down time for my daily driver.
Thanks! Art
03-14-2018, 12:02 PM
#3
Ive had a 4L60 become soft shifting. Trans shop told me that the 2nd gear check ball can imbed itself into the shift plate. I took it to them and sure enough, it was. They sent me pix and said they could knock the ball out and flatten the plate again but recommended getting a replacement Transgo shift plate. I had them put in the Transgo shift plate and it shifts very firm now but not knock your head off. I love it.
03-15-2018, 09:06 AM
#4
TECH Enthusiast
Thread Starter
Lost 4th gear in that it will not engage, the truck will over power 2nd but 1st gear is fine holding power. The 2-3 shift has a little authority
03-29-2018, 03:04 PM
#7
TECH Enthusiast
Thread Starter
trans builder stated the 2-4 band was gone, I had mytuner dial down the trans pressure in the tune and the shop added the sonnax variable pressure spring in the pump. The guy who test drove my truck said it chirped 3rd gear and will warranty his work (1year 20,000 miles) once I had the trans pressure returned to stock. The good news is it’s still a beast at WOT and much more civilized at part throttle
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04-07-2018, 02:14 PM
#8
TECH Enthusiast
Thread Starter
welp, the rebuilt trans decide to grenade some hard parts after hitting a pack of shingles??? in the road. It happened during a soft left turn and during a shift BOOM