Volvo a40. Dropbox locked up

[chris dials]

Hi all.
I’ve got a Volvo a40. 1997 era
Been working great. Randomly yesterday while hauling it locked up and came to a stop. Almost like I mashed the brakes. No noise or carnage like anything broke. It won’t go forward or reverse. It goes into gear, can hear a load being placed on the engine. Drive lines only move about a quarter turn in either direction. Pulled the drivelines off at the Dropbox and have the same issue. Drained it and no metal in Dropbox. I’ve heard it could be electrical but the monitor screen doesn’t work so I can’t see any codes. Anyone experience this issue before and what was the problem. Thanks

 

[Bigbert]

Hi Chris,

I'm not a real expert in Volvo's. However looking at sectional drawing of drop box I can only imagine a broken tooth locking box. The sleeve for L and H usually only moves in Neutral at standstill. Electrically I do not see a chance for locking. Presumeably it is one solenoid moving sleeve with air or oil.
Parkbrake is behind articulation pivot, so we can exclude.

 

[funwithfuel]

Have you checked the oil

 

[Nige]

Drained it and no metal in Dropbox

It appears so.

 

[funwithfuel]

I would pull the oil cooler off the front bearing retainer. See if its discolored or has a bulge. The interaxle differential is what usually grenades. If it has, you may have gotten lucky with a clean break. More often than not, there's debris everywhere. Either way it looks like you'll be pulling her out.

 

[funwithfuel]

You may want to pull the prop shaft between the transmission and dropbox. Be careful, you have to tie the dropbox back to the frame . You might have blown the rear section planetary