Allison 5sp: P0776 help mike!

REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
I had this trans rebuilt about a year ago. After I got it back I noticed it would jump out of gear while sitting still and (D) would flash. I took it back to the mechanic and he said "it's still in learning mode" over time I still had the same problem. After "warranty" was up he said we'll have to pull it and see whats wrong!! SCREWED AGAIN! So i wasnt going to pay him to screw it up again. For the past week we have had icy roads and I have been running in 4hi for about 3 days straight. Well yesterday I was cruising at about 35mph and the RPM's shot up, I am in 2wd so i thought i hit an icy spot in the road. As I looked in the mirror I noticed the road was clear. Then it did it again, 1-2-3-zing then i let the rpms drop and it goes into 4th. Fluid smells a little burnt, un hooked battery to reset codes and didnt work. Where do i go from here?
 
Mike L.

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
REDHOSS02 said:
I had this trans rebuilt about a year ago. After I got it back I noticed it would jump out of gear while sitting still and (D) would flash. I took it back to the mechanic and he said "it's still in learning mode" over time I still had the same problem. After "warranty" was up he said we'll have to pull it and see whats wrong!! SCREWED AGAIN! So i wasnt going to pay him to screw it up again. For the past week we have had icy roads and I have been running in 4hi for about 3 days straight. Well yesterday I was cruising at about 35mph and the RPM's shot up, I am in 2wd so i thought i hit an icy spot in the road. As I looked in the mirror I noticed the road was clear. Then it did it again, 1-2-3-zing then i let the rpms drop and it goes into 4th. Fluid smells a little burnt, un hooked battery to reset codes and didnt work. Where do i go from here?
Click to expand...

Output speed sensor or transfer case is where I would start.
 
M

Mike

hmmm....
Feb 17, 2007
2,184
0
36
San Angelo, TX
REDHOSS02 said:
aNY TIPS ON REPLACING THIS SENSOR?
Click to expand...

Might check the sensor end to see if anything is hitting it.

Transfer Case Speed Sensor Replacement

Removal Procedure



  1. Raise and suitably support the vehicle. Refer to Vehicle Lifting.
  2. Disconnect the speed sensor electrical connector.
3. Remove the speed sensor.Installation Procedure



  1. Notice: Refer to Fastener Notice in Service Precautions. Install the speed sensor.

    • Tighten the sensor to 15 Nm (11 ft. lbs.) .


  1. Connect the speed sensor electrical connector.
  2. Lower the vehicle.
 
Sledhead

Sledhead

Mountain Pass Machine
Nov 29, 2008
884
0
16
BC
I would be inclined to drop the oil on the transfer case and have a look, and get the codes that are set now.
 
Mike L.

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
Update

Took my truck to the stealer to have them diagnose. Supposedly 4th gear is SHOT! Which has me confused because it was only slipping in between 3rd and 4th unless it was jumping straight to 5th. I was criusing at between 40mph and 80mph on the way to the stealer. Give me some input guys.
 
Sledhead

Sledhead

Mountain Pass Machine
Nov 29, 2008
884
0
16
BC
Sounds like you need to go back into it but how did they determine "4th Gear is shot"? Did you pull the codes before it went in? Or get the codes from them. Bump for a guru to see...
 
REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
I pulled the codes before i took it in. They pulled the codes again and dropped the pan and noticed alot of metal shavings in the pan on the tranny and stuck to the magnet. They said they couldnt seem to find anything wrong with the transfer case. Im stumped! He said why dont you just eliminate your headaches and buy a new tranny for $5,400?!?!?!:roflmao: hahahahahah I can have a bad ass built trans for that much.
 
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