Kfloyd76

Installed a 5.3 out of a 05 suburban and a 4l60e trans out 0f 03 2wd Silverado into a 85 c10 used the factory fuse box out of 05 suburban and wired using info off of lt1 website. Trans shifts good in 1st and second but goes into neutral shifting into 3rd. Dont want know if it's just the common problem with the trans and need new one or rebuilt or if the wiring is the problem. Ran 12v power to c1-c9 and when on scanner no trans codes. Unplug trans plug and get multiple trans codes. Dont want to replace trans and not be the problem any help would be great.

8.Lug

Just dump that 4L60. Even if the 3/4 clutch pack isn’t bad, it’s gonna need to be opened anyways to find out what’s wrong. Cut your losses now.

98CayenneT/A

Did you drive it with the trans plug disconnected?

Kfloyd76

With trans plug unplugged it has reverse and first gear

98CayenneT/A

No 3rd ?

Kfloyd76

Just seems like 1st gear in drive or manually shifting thru trans

Kfloyd76

Was told that by a couple mechanics the 4l60e being electronic would only have first and reverse with no power. The guy that flashed the computer said it should manually shift thru 1st 2nd and 3rd

98CayenneT/A

With the harness unplugged you should have 3rd.

someone else would have to confirm this but outside shot that solenoid B is stuck on.

Kfloyd76

Could it be the harness inside the pan causing the problem, obviously could be solenoid or could it be the way I have the trans wired in fuse box? I know I'm getting power to trans and no codes for trans unless I unhook plug at trans or disconnect the power going to c1-c9. I've also tried power to the c2-e11 with no change

JoeNova

Losing 3rd is extremely common with the 4L60e.

Jays_SSZ28

iTrader: (2)

No power to the transmission puts it in third.
Could be a mechanically stuck solenoid if it's not in third while unplugged, its not very common to fail like that.
Its that simple, there are no what if's, you unplug it, its in 3rd.
If third was burned up it would act like neutral.

Kfloyd76

I'll unplug it again tomorrow and take it for a drive. Anyone on here successfully wired the fuse box and harness per the lt1 website for the engine and 4l60e trans swap?

Kfloyd76

With trans power unplugged the trans has reverse you shift into drive and it's in first and will smoke the tires as long as u want. Shift into low gear and it acts like it's in 3rd, manually shift into 2nd and it goes into neutral. Again when u plug trans in it has first and 2nd then slips into neutral when in drive

Jays_SSZ28

iTrader: (2)

See someone with a scanner

MaroonMonsterLS1

So...UNPLUGGED you get 1st gear with the selecter in D (around here D=3)?

What happens if you leave the shifter in OD aka 4

But if you pull the shifter into 1st...then you get 3rd?

Sounds like some bass ackwards stuff...Get a scanner on it...Leave it in OD (4) and command gears with the scanner