Volvo gutless at take off

[Nige]

The good old Catch-22. Can't get boost pressure without RPM. Can't get RPM without boost pressure.

Anything possibly to do with the torque converter side.? Wrong (too heavy) oil maybe.?

We used to run into it a lot at high altitudes. Often the solution (provided the converter had a lockup clutch) was a different turbine wheel with less vanes to allow it to "slip" more when the machine was trying to take off from a dead stand. This allowed the RPM to increase faster and thus to get more boost. Once the lockup clutch engaged it didn't make a blind bit of difference to the drive. Eventually the field fix became a "High Altitude Converter" option in the machine price list.

 

[colson04]

Knowing how maintenance on the farm generally runs, I would bet the transmission has whatever fluid was in it from time of purchase. That said, it looks, smells, feels like transmission fluid and the fluid level never changes.

I climbed under our other automatic, and I think the tag said 5.36 for gear ratio. Hard to tell, dark and slightly rusty. It was definitely a 5.xx something ratio.

 

[Truck Shop]

536 or 556 I would think. IMO for the amount of weight verses torque verses ratio. That's a crap load
to ask of a 7 plus liter. A higher stall converter might help but expensive. What would be good to see
is a chart showing torque curve/rpm for that engine. It seems to me it's struggling to climb the torque
curve possibly because of too high ratio.

 

[56wrench]

A slipping stator in the torque converter would cause poor take-off but it would likely also be noticeably worse empty. So, i would guess maybe a mismatched torque convertor for your application or as others have said, not a deep enough axle ratio

 

[colson04]

That's a crap load
to ask of a 7 plus liter.

Yes, I think that is the problem with what I'm experiencing. Just not enough torque for the job. Truck should probably have a 10 liter for what we're using it for.

 

[thepumpguysc]

All the gov. adjustments are going thru the computer..
Not even a boost adjuster on the pump.. like a normal “P” pump..
There’s only 1-2 shops that are certified to do an “H” pump in the country..
I would be looking around the turbo/intake/waste gate for some kind of adjuster.. and a test port so u could check boost at the intake..
Sorry.. but that’s all I got..
Good luck.

 

[fast_st]

I'd almost bet the emissions or fuel economy is spot on, no fueling down low. We had a fire engine, it was dreadful, mat the throttle and wait, hot/cold didn't matter, pulling into traffic was tough, was a few seconds of lag before it started to make any power. Seems there was an 'eco' program that was loaded, it was a simple software change. I think yours may be more hardware especially if it was originally california.

 

[Delmer]

yes, 98 and California should have said it all.
Forget Pumpguy, these guys have it all figured out, I'm sure they'll get you running like a big cat in no time. http://www.competitiondiesel.com/forums/showthread.php?t=155364

 

[Steve 72]

Have a vovlo d7 doing the same thing did you have any luck figuring it out?

 

[colson04]

Have a vovlo d7 doing the same thing did you have any luck figuring it out?

No, truck is still the same. We don't haul much grain with is anymore as we got a second semi truck last fall. Boss said don't mess with it. It has plenty of go for hauling silage.

 

[Steve 72]

Thanks