Hard 1-2 shift on LS swap, Need help
Thread Starter
Teching In
Joined: Jul 2024
Posts: 1
Likes: 1
Hard 1-2 shift on LS swap, Need help Hello I need some help with my 94 F150 LS swap.
I think that i have a problem but im not entirely sure. It could be 100% tune, but i have been trying to fix small things that have been effecting the drivability so i haven't had time to get back with my tuner.
As it stands right now I am on the 3rd transmission. The 1st blew because i was not 100% sure what was going on when i put it together the first time. No tune at all. The 2nd time the torque converter let go and the transmission followed.
Which Transmission
4L60E (about 2,500-3,000) miles since fresh rebuild.
-Which powertrain management
Stock PCM, self trimmed wiring harness
trailblazer intake 92mm throttle body, drive by cable(Not computer controlled butterfly)
-Have you ever checked line pressures?
No, and im not entirely sure how to. But it has good pressure, maybe to much.
As far as i can remember it has always hit hard into 2nd. Under normal acceleration it kinda bumps into second not to bad. But off the line, full throttle it slams into second and breaks the rear tires loose.
Iv blown a transmission line several times, so it has fresh and clean fluid in it. Iv been checking it weekly and the level is perfect. I put a new filter and gasket on the transmission in September.
Anything is appreciated. Thank you!
I think that i have a problem but im not entirely sure. It could be 100% tune, but i have been trying to fix small things that have been effecting the drivability so i haven't had time to get back with my tuner.
As it stands right now I am on the 3rd transmission. The 1st blew because i was not 100% sure what was going on when i put it together the first time. No tune at all. The 2nd time the torque converter let go and the transmission followed.
Which Transmission
4L60E (about 2,500-3,000) miles since fresh rebuild.
-Which powertrain management
Stock PCM, self trimmed wiring harness
trailblazer intake 92mm throttle body, drive by cable(Not computer controlled butterfly)
-Have you ever checked line pressures?
No, and im not entirely sure how to. But it has good pressure, maybe to much.
As far as i can remember it has always hit hard into 2nd. Under normal acceleration it kinda bumps into second not to bad. But off the line, full throttle it slams into second and breaks the rear tires loose.
Iv blown a transmission line several times, so it has fresh and clean fluid in it. Iv been checking it weekly and the level is perfect. I put a new filter and gasket on the transmission in September.
Anything is appreciated. Thank you!
Last edited by 94Ford5.3; Jan 16, 2025 at 04:01 PM.
TECH Junkie
Joined: Dec 2012
Posts: 3,615
Likes: 1,327
From: Iowa
Impossible to help you
You need to share:
-Which Transmission
-Which powertrain management (Stock ECU, Holley, Carburetor and a standalone trans controller, etc)
-If the trans has been built...what has been done to it. Namely info on the accumulator and the shift orifice sizing
-Have you ever checked line pressures?
You need to share:
-Which Transmission
-Which powertrain management (Stock ECU, Holley, Carburetor and a standalone trans controller, etc)
-If the trans has been built...what has been done to it. Namely info on the accumulator and the shift orifice sizing
-Have you ever checked line pressures?
