4L80e no reverse sometimes
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4L80e no reverse sometimes I have a 4L80e in my motorhome that the reverse works off and on , When I shift in reverse you can hear and feel it engage but act like it in neutral all other gears work great. But sometimes the reverse does work and works great but then when I shift it to drive and back again its gone.
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yes filter changed 5000 miles ago about 2500 mile after the change is when reverse started acting up I just changed it again thinking the filter must of been clogged but still no reverse. The shift linkage seem to be right I have all the gear park is in the right place.I was going to pull out the Reverse Servo Piston "the pan is all ready off" and see if there anything wrong with it could that cause that type of problem?
I had that problem with my 4L80E at 60,000 miles.
The band pin was too short allowing the reverse servo to slam against the case on apply.
I went as far as replacing the band and it worked for a short time.
Then I put a longer apply pin in and it work for a short time again.
I finally pulled the servo piston again and found a hairline crack around the sealing ring groove, I actually pulled it with a fingernail and it broke off. Replaced the piston and haven't had a problem with it in 13 years.
The band pin was too short allowing the reverse servo to slam against the case on apply.
I went as far as replacing the band and it worked for a short time.
Then I put a longer apply pin in and it work for a short time again.
I finally pulled the servo piston again and found a hairline crack around the sealing ring groove, I actually pulled it with a fingernail and it broke off. Replaced the piston and haven't had a problem with it in 13 years.
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Joined: Oct 2016
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Thank you I'v pulled the valve body and reverse servo and after cleaning to up will look for problems , I pray I find something so I do not have to pull the trans
I had that problem with my 4L80E at 60,000 miles.
The band pin was too short allowing the reverse servo to slam against the case on apply.
I went as far as replacing the band and it worked for a short time.
Then I put a longer apply pin in and it work for a short time again.
I finally pulled the servo piston again and found a hairline crack around the sealing ring groove, I actually pulled it with a fingernail and it broke off. Replaced the piston and haven't had a problem with it in 13 years.
The band pin was too short allowing the reverse servo to slam against the case on apply.
I went as far as replacing the band and it worked for a short time.
Then I put a longer apply pin in and it work for a short time again.
I finally pulled the servo piston again and found a hairline crack around the sealing ring groove, I actually pulled it with a fingernail and it broke off. Replaced the piston and haven't had a problem with it in 13 years.
