Volvo a25c shifting and 6x6 issues

[Aaron93]

Hey everyone. I am currently having an issue with my a25c articulating dump truck.

Originally, the truck didn’t shift gears unless we turned it off and then shifted into forward and reverse. Since then, we have serviced the tranny and took the valve body completely out and cleaned it (wasn’t burnt, dirty, and no metal fragments). Now the truck will shift into forward and reverse while it is on but it still won’t shift from 1 to 2 while driving and no 6x6. We checked the wiring and found a couple of minor issues and fixed those too.

Please let me know what I should look into next, thanks!

 

[Mark250]

check your output speed sensor
Do you have the overhead display?

 

[sfrs4]

also check the linkage to the load sensor, it come from the fuel pump governor, with a short piece of rod with a l/h thread rose joint on one end and a r/h thread rose joint on the other, if loose it will cause all sorts of shifting issues below is your load sensor. and below that the linkage.

 

[Aaron93]

Ok thanks for everyone’s help! It looks like it was a few issues.

First of all, the the connector on the top of the transmission wasn’t attached very well and that caused a few issues with the valves opening and closing. That seemed to have solved switching from forward to reverse and changing gears in drive mode.

Secondly, our workers that run this truck aren’t technical savvy and a few of the relays weren’t atttached very well and a few of the torpedo fuses were missing. This caused a few issues with the overhead display.

Third, the alternator wasn’t grounded properly so the system was constantly undercharged.

Fourth, Volvo seems to put shotty wire connections on the air servos going to the diff lock and 6x6 lock. We modified our wires to fit on the connectors better.

With all that said we seemed to have fixed most of the issues so far.

I still would like to see a relay and fuse diagram for everything in the cab if anyone has access to that. Also what’s the proper voltage that we should be seeing on our overhead display. We were at 24.5v before now we are at 26.6v with the better ground.

 

[Mark250]

Hi fuses

 

[Mark250]

Hi relays