LS1LT1 Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I have came from a father who build race engines and mechanical contractor. I have learned everything I know from him.
this is my first 4L60E build. After I paid a professional a hand full of time. I decided it was time to rebuild myself. I followed the popular Manuel as far as clearances. Although I have read on this form that they are a bit more then what ispreferable. So I finished installing the transmission lastnight.
The test drive started great first second gear are strong. When it finally shifted into 3rd if I hadn’t of been paying close attention it would have red lined. I have steady researched and the only possibility is the 3-4 return springs that I now know to remove and discard. Maybe they are installed upside down? Is this possible? The other possibility is the valve body. I purchased it on eBay relatively cheap compared to the Sonnex gm048. The test drive was after the truck satin idled and reach temperature prior to test drive. Only drove about 6 miles in second gear. Stopped at a gas station fueled up. On the way home the problem got worse. Slipping in second gear as well. The transmission temp never got above 165 degree. I luckily was patient enough to make sure that the new temp gauge was operational prior to test drive. So this is what I am aware of. Pressure setup will be in hand tomorrow. I’ll be checking the pressure to verify this is not a pump issue.
any advice as to how and where I should start to get this issue resolved? Thank you ahead of time.
 

·
Global Moderator
Joined
·
13,110 Posts
There's another possibility and it has nothing to do with the trans itself. The program in your car's computer may be causing the car to want to bounce off the red line before shifting to 3rd.

Your 4l60E is computer controlled and the solenoids inside get signal from computer as to when to energize the solenoids. If computer has program tables with the wrong speed / rpm info selected, then computer will have either early or late shifts.

Unfortunately I can't look at the info programed into your computer to see if trans data is correct. It would take a programmer like www.lt1pcmtuning.com

I'm not saying this is your problem for sure. But it could be.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #3
Okay I know a man with HPTunes, it’s 150$ for the vin credit.
I don’t have a lot in the department.
How is my question? The truck has sat without a transmission or battery for 15 months or so. Prior to jack stands the Silverado drove around.. hold one a sec it was doing this exact thing. Although the tranny was 2 years old and I had a cooler line blow off pulling out of a gas station turning up. I knowingly filled with fluid from tractor supply that was not correct. The wife took me for granted and drove all over the next day. Doing so destroyed torque converter clutch sending the debris through the transmission. Starved the rear planetary of fluid what happened next is simple. At that point it wouldn’t move in reverse and only 1st gear would move struggling.
I recon the truck still thinks the previous problems still exist. that makes sense. I am going to reach out HPTunes man.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
There's another possibility and it has nothing to do with the trans itself. The program in your car's computer may be causing the car to want to bounce off the red line before shifting to 3rd.

Your 4l60E is computer controlled and the solenoids inside get signal from computer as to when to energize the solenoids. If computer has program tables with the wrong speed / rpm info selected, then computer will have either early or late shifts.

Unfortunately I can't look at the info programed into your computer to see if trans data is correct. It would take a programmer like www.lt1pcmtuning.com

I'm not saying this is your problem for sure. But it could be.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #5
Okay I have the tranny out and the clutches look new as does the band. So if it were a electronic issue, why all of a sudden?
I am replacing the high energy BW clutches with the zpack and superior bullet 4th gear servo kit since I have this apart now. I also have thw sonnax gm048 VAlve body for this application. after I get it all back together I’ll post the status. And go from there.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6
Okay I found the problem while I had the input drum apart. The sprag installed backwards. Perfect reason for no 3-4
 
1 - 6 of 6 Posts
Top