Early volvo L70 tranny issue

[scooter01922]

Ok guys, heres another issue i need a little help with. I bought this very well used L70 from a friend whom had it and knew its history very very well before he got it. Machine spent its entire life pushing cardboard around a recycling plant. LOTS of hours (36K i think) but not a lot of hard work, no welds, pretty well maintained. Pins are tight and no real leaks. Shortly after he got it it was left on a job site and someone either snuck in and started it or left it running over the weekend. Crew came in monday and it had dropped oil and coolant everywhere and run till seizure. Unable to find a 4 cyl volvo motor to put in he sourced a relatively recently rebuilt 6 cyl volvo motor from an L90 that was the eventual upgrade the L70 got later in its production. When i came on the scene his guys had gotten the motor in the frame and bolted up and then business got busy again and there was no time to mess with it. I got it mostly finished, had to make a custom relocation flange for the turbo, move the rad a bit and a boatload of other things. Runs very nicely, everything was working fine with the exception of the brakes but thats a story for another time. Hauled it from his place to a local farm where i have done a lot of trucking, better place than home to mess with it and see what works and what doesn't. Very first time i go to try and see what its got for grunt something went wrong. Pushed into a pile of screened loam, nice and easy. Pushed pretty good, shift into reverse to back out and ......nothing. Back into forward, NADA. Master caution light came on. Shut it off and went looking for a blown line or a linkage off or something but there isn't anything obvious. Will not restart as the master caution light apparently disables the start circuit. Jumped the starter solenoid and fires right up. Hydraulics worked fine so dumped the bucket and crutched myself out of the way with the bucket. Fluid level in tranny is fine and it there was something really really wrong i should have lost hyd too i would guess. Went looking and the tranny computer was already bypassed so its already in manual selection mode. Short of manually engaging gears on the tranny valve body which the manual describes but then advises not to do unless necessary i'm not sure how to figure out what the hell is going on. The manual is very vague about the master caution light, tells you its for a bunch of things but not really what they are. I do have the ops manual, the parts manual and the repair manual. Something is obviously not happy and its telling me so, now what is it? Any advice appreciated.

 

[Volvomad]

Did not think the central warning system would dis able starter circuit. Gear lever in forward or reverse will. Surely electrical. If you could borrow a gear lever from some one it might be worth a shot. I had to rewire one of those from the plug in the fuse box to the transmission solenoids as the insulation started falling apart from heat and time with less than half them hours.

 

[James Sorochan]

On my L90C I lost reverse intermittently then after some time lost both forward and reverse. I pulled apart the shifter and checked the micro switches finding a big difference on continuity reading so got some new micro switches and saudered them in. Works ok but still occasionally blows 5 amp fuse for shifter. For now I'll keep a few extra fuses handy. It doesn't take to long to take apart and check.

 

[funwithfuel]

L70 Volvo or VME?

 

[scooter01922]

Did not think the central warning system would dis able starter circuit. Gear lever in forward or reverse will. Surely electrical. If you could borrow a gear lever from some one it might be worth a shot. I had to rewire one of those from the plug in the fuse box to the transmission solenoids as the insulation started falling apart from heat and time with less than half them hours.

Its entirely possible it won't and the master caution just happened to come on at the same time. I had noticed some insulation at the shift solenoids that looked a bit weather checked. Was seriously hoping to avoid a major rewire but if need be...

 

[scooter01922]

L70 Volvo or VME?

VME i believe, its first series L70. Don't have the literature in front of me at the sec.

 

[funwithfuel]

Where's the fuse panel?

 

[scooter01922]

On my L90C I lost reverse intermittently then after some time lost both forward and reverse. I pulled apart the shifter and checked the micro switches finding a big difference on continuity reading so got some new micro switches and saudered them in. Works ok but still occasionally blows 5 amp fuse for shifter. For now I'll keep a few extra fuses handy. It doesn't take to long to take apart and check.

Sounds like a good place to start just odd for them to both crap out at the same time. Or maybe one crapped out and is canceling out the other?? not sure how the machine would handle conflicting inputs.

 

[scooter01922]

Main fuse panel is just inside the door, big swing open door on the left side of the cab

 

[funwithfuel]

So, when she's running, do you have main and lube pressure in the trans? Was the torque converter a good fit in the flywheel?

 

[scooter01922]

I wasn't there for the actual engine install but this engine is coupled with that tranny in the later L70 models. Was told it bolted right up. No idea on pressures, ran it as short a time as possible getting it out of the way and really haven't messed with it since. Should look up where the test ports are and what pressures its running so i can finagle some appropriate gauges.

 

[scooter01922]

My first thought was that maybe they didn't bolt the torque to the flywheel completely and i sheared whatever was actually bolted with that first push. Then i thought some more and concluded that couldn't be the case since the hydraulics all work like normal with full pressure. If the flywheel wasn't spinning the tranny it wouldn't be spinning the pump either, at least thats my train of thought.

 

[funwithfuel]

I think on the straight models, the pumps were driven by the PTOs on either side of the flywheel housing, not by the trans. I could be wrong, but I don't think so.

 

[scooter01922]

Hmmm, well i guess i'll be needing to take a little drive over to the farm and have a peek.

 

[funwithfuel]

If it were an E model or newer, I'd agree. It's been a while, to be honest, I wouldn't swear to it.

 

[sfrs4]

sounds daft but have you checked to make sure the forwards reverse lever isn't buggered and its now holding the gear signal hence stopping it from starting, but then it would also hold the actuation of the travel I suppose

 

[funwithfuel]

sounds daft but have you checked to make sure the forwards reverse lever isn't buggered and its now holding the gear signal hence stopping it from starting, but then it would also hold the actuation of the travel I suppose

That would also prevent starting.

 

[scooter01922]

sounds daft but have you checked to make sure the forwards reverse lever isn't buggered and its now holding the gear signal hence stopping it from starting, but then it would also hold the actuation of the travel I suppose

I was thinking of that recently whilst out driving from point A to point B for work.....had a couple hours of thinking time that day. But wouldn't that make the damn thing want to move once i did start it?? Would certainly keep it from starting normally. I mean unless its getting conflicting signals, not sure how the forward reverse switches are engineered but if it was somehow trying to do both what would it do??? Did look at the repair manuals i have, not sure what PTOs are being referenced on the side of the tranny to drive the pumps. Parts breakdown shows a torque converter with some damn strange looking shafting of some sort through the center and gears and.... Frankly the exploded parts view is great but its a little tough imagining it in one piece and how its functioning.

 

[karlbradshaw]

Hi guys, did this get sorted?

I have an early L70 and it won’t start. No signal to starter solenoid although live leaving the ignition barrel.

Shorted starter and got running but no gears. Not sure what’s happened but the ecu glass fuse has blown and keeps blowing. I guess the gearbox / ecu fault is causing the starter interlock to engage.

Any help greatly appreciated

thanks

 

[Volvomad]

You can bypass the transmission ecu by swapping a plug on the electric panel. If fuse issue is in ecu you should be able to work without it. If not , i would hope the bypass circuit is fuse protected and that one may blow.