1992 GMC only 2nd and reverse, wont shift

Reply

  #1  
Old 03-24-09, 08:11 PM
michaeljp86's Avatar
Member
Thread Starter
Join Date: May 2005
Location: USA
Posts: 478
Question 1992 GMC only 2nd and reverse, wont shift

I have a 1992 GMC with a 4L80E automatic and a 6.5L engine. Over about a month it kept shifting at higher and higher rpms until finaly it wouldnt shift anymore. I can get up to about 45mph so I think its in 2nd. Reverse works fine but 1,2,3,d, and od is all the same gear. The fluid level is fine and its not burned. Any idea on what the problem is?
 
Sponsored Links
  #2  
Old 03-25-09, 12:27 PM
badeyeben's Avatar
Member
Join Date: Dec 2006
Location: Southern ILLINOIS
Posts: 943
The shifting is controlled by the vehicle computer. Do you have a check engine light on? You will need to have the codes read and go from there. Did the battery go bad? Sometimes the battery being discharged or off for a while messes up the computer.
 
  #3  
Old 03-25-09, 12:49 PM
michaeljp86's Avatar
Member
Thread Starter
Join Date: May 2005
Location: USA
Posts: 478
No check engine light, and the batteries are fine and always were.
 
  #4  
Old 03-25-09, 03:56 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,540
Check for codes anyway; the tranny codes do not necessarily light the MIL lamp. I have the 4L80E in my '94 wrecker and it will store tranny codes with no MIL. Your symptoms also sound vaguely familiar but so far I haven't been able to pull anything from memory.

How many miles on it?
 
  #5  
Old 03-25-09, 04:54 PM
michaeljp86's Avatar
Member
Thread Starter
Join Date: May 2005
Location: USA
Posts: 478
The truck has 250k on it but the transmission was supposed to have been rebuilt a year before I bought it and I have only put about 150 miles on it.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'