I have a 4l80 that is on a bench awaiting the swap. I also have the transfer case swap out gear from Speed Engineering which allows me to use the 4l60 T-case. The swap out gear, female spline fits too big over the male tailshaft of the 4l80 and does not engage. So either the swapout gear was cut wrong or I have a 2WD 4L80 instead of a 4WD. Pleeeeeaaassseee Help! How can I tell if its a 2WD 4L80?

 

Who did you get your 4l80e from? Is it possible that your trans has been setup with the same output spline as a 4l60e? Try to slide your transfer case onto the 80.

 

The transmission is a 2005 takeout from a junkyard.

 

Does your transfer case slide onto the 80? Also how many splines are on the output shaft? Count the splines on the gear speed sent you.

 

The gear speed sent has 29 splines. I have to go to the shop tomorrow to count the splines on the output shaft.

 

sounds like a 2wd 80e, yikes...did it come with the adapter housing that seperates the trans from the t-case?

 

If you can't tell from the output shaft length, the easiest way to tell if it's a 4WD 4L80-E is to look at the rear VSS sensor. On the 4WD unit this is plugged.

 

Yes there is an adapter housing so Im hoping that the speed engineering spline adapter is cut oversize. Does the adapter housing indicate that is a 4wd?

 

I will check tomorrow at the shop. Can you advise if the output shaft spline size diameter is identical for both 2wd and 4wd 4l80's. If so my speed engineering adapter is the problem. The speed eng adapter fits oversize to the output shaft of the tailshaft.



SOS

 

Yes both 2wd and 4wd have the same spline diameter but the 2wd one is longer.