4L80E will not go into reverse

[4x4soldier]

I loaned my 1999 GMC 2500 with a 6.0 and a 4L80e to a friend. It was working fine. He brought it back and said that reverse just stopped working? Today I've tried everything, checked the fluid, disconnected the battery for a few hours, drove it around the sub-division, come home nada, no reverse. Fluid looks fine, forward gears are fine. Any idea's?

Thanks,

 

[cj7-377]

sounds like broke sun shell gear. does it have all forward gears no low gear

 

[cash talks]

there is a solenoid that is pretty easy to replace if you pull the pan off. fairly common for the 80e. contact Blacksheep10. he knows more about them

 

[4x4soldier]

Yep goes forward fine. Shifts all the way through the gears and all. Just no reverse.

 

[InDaShop]

Could be the electronics, which can be tested. If still no reverse move onto the mechanical tests

You want to read this.
http://www.sonnax.com/publications/transmission/titles/diagnosing-the-elusive-no-reverse-with-the-4l80e

 

[KILLERB468]

if all forward gears work, and no manual low/1st gear most likely it is a busted rear band.

 

[Cornbread Customs]

Yea, the 80e's were bad about line pressure spiking when you put it in reverse and it eventually screws up either the band or the piston for reverse. I bought my truck 3 yrs ago dirt cheap just because of that. It doesnt hurt anything but just doesnt engage reverse. I went to texas and drove mine back to oklahoma 400 miles like that


Go BIG Or Go Home!! ????

 

[Lil ugly]

Could be the electronics, which can be tested. If still no reverse move onto the mechanical tests

You want to read this.
http://www.sonnax.com/publications/transmission/titles/diagnosing-the-elusive-no-reverse-with-the-4l80e

That is a good tech article.