Think i found it!!!Rebuilt 4l80e slipps, but not when unplugged
07-29-2012, 10:53 PM
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Think i found it!!!Rebuilt 4l80e slipps, but not when unplugged Hello
Really need some help and advice here. Been searching the net but can't find what I am looking for.
Bought 98 2500 with bad transmission. Being a project truck I wanted to do the rebuild myself. Truck pulled on trailer when I bought it.
I purchased rebuild kit and converter. Cleaned everything and rebuilt.
Replaced no electronics.
Trans will go into gear but slipps like crazy, will hardly move. Reverse seems good though.
I read somewhere to unplug harness, I did and it does not seem to slip.
But does not seem to have first gear.
On jack stands with harness plugged in and manually shifting, you can see each gear as the tach changes.
Scanned for codes after running it and it didn't have any.
Checked pressures and reverse pegged my 180 gauge, and was 40 to 50 at idle.
Idle in park is 45 to 50
Drive was 70 at idle, 60 when freewheeling on jack stands
Third was 70 at idle and 75 when reved on jack stands
Second 90 at idle and drops to 80
First was 110 at idle and 130 when reved on jack stands.
I don't know if that was the correct way to test pressures or not.
Plan on buying the force motor and other solenoids.
Any help or insite is much appreciated, just wondering if I'm going the right direction.
Really need some help and advice here. Been searching the net but can't find what I am looking for.
Bought 98 2500 with bad transmission. Being a project truck I wanted to do the rebuild myself. Truck pulled on trailer when I bought it.
I purchased rebuild kit and converter. Cleaned everything and rebuilt.
Replaced no electronics.
Trans will go into gear but slipps like crazy, will hardly move. Reverse seems good though.
I read somewhere to unplug harness, I did and it does not seem to slip.
But does not seem to have first gear.
On jack stands with harness plugged in and manually shifting, you can see each gear as the tach changes.
Scanned for codes after running it and it didn't have any.
Checked pressures and reverse pegged my 180 gauge, and was 40 to 50 at idle.
Idle in park is 45 to 50
Drive was 70 at idle, 60 when freewheeling on jack stands
Third was 70 at idle and 75 when reved on jack stands
Second 90 at idle and drops to 80
First was 110 at idle and 130 when reved on jack stands.
I don't know if that was the correct way to test pressures or not.
Plan on buying the force motor and other solenoids.
Any help or insite is much appreciated, just wondering if I'm going the right direction.
Last edited by st1977; 08-03-2012 at 05:50 PM.
07-30-2012, 05:58 AM
#2
your pressures dont look way out of line from some old recorded ones i had, but your park one is low-i had the HD-3 man kit, and with the mod they were lower, like yours, so could possibly be your force motor, if the ecu is good
its always a good idea to change all the elects
hopefully someone else will chim in
i think you have rev and 2nd unplugged as i remember
its always a good idea to change all the elects
hopefully someone else will chim in
i think you have rev and 2nd unplugged as i remember
07-30-2012, 02:16 PM
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your pressures dont look way out of line from some old recorded ones i had, but your park one is low-i had the HD-3 man kit, and with the mod they were lower, like yours, so could possibly be your force motor, if the ecu is good
its always a good idea to change all the elects
hopefully someone else will chim in
i think you have rev and 2nd unplugged as i remember
its always a good idea to change all the elects
hopefully someone else will chim in
i think you have rev and 2nd unplugged as i remember
I purchased all the electronic solenoids today. Hopefully this will fix it.
07-31-2012, 11:06 PM
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You should always replace the epc solenoid during a rebuild. those pressures are too low.
Also look at replacing the boost valve
the reason it doesnt slip when unplugged is because it make it default to max pressure when unplugged
Also look at replacing the boost valve
the reason it doesnt slip when unplugged is because it make it default to max pressure when unplugged
08-03-2012, 05:19 PM
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I think I found the problem. I installed the lower rollers upside down. When installed like this the shaft will spin both ways in the lower portion. I flipped the bearing around and it only free spools one
Way.
This sound right?
Way.
This sound right?
08-04-2012, 10:07 PM
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Just to update to anyone who has read this, I assembled
The trans today with the lower roller clutch bearing the right way and put it in truck. Works like a champ :-). Stupid mistake, I know. Should have watched the videos on YouTube all the way through on how to assemble lol.
The trans today with the lower roller clutch bearing the right way and put it in truck. Works like a champ :-). Stupid mistake, I know. Should have watched the videos on YouTube all the way through on how to assemble lol.
