Front wheel drive doesnt work

[Fairfax]

In this case what does "hop or hopping" mean please?

Often times when your stuck or pulling something (stump), your wheels will slip and then grip in rapid succession while they spin, causing the machine to hop or bounce. This loads and unloads the drivetrain very quickly, possibly causing something in the drivetrain to snap. Especially when something as heavy as a tractor starts hopping.

 

[holeycow]

perfect.

I could not have said that better myself...or even nearly as well. Thank-you.

 

[GManBart]

Since it is obviously a defective part due to over hardening the shaft which made it too brittle and should be covered regardless of how they perceive it.

No offense, but you don't have anything to support that....there just isn't any evidence other than "it shouldn't have broken" which isn't certain either.

Driveshafts are rarely covered by warranties, for good reason...they can be broken through "normal" use, and not be faulty. They're intended to fail before expensive parts break, and at only $125 you're pretty lucky.

It's also possible that in the past you did something to damage the shaft (like start a crack), and it didn't fail completely, and pushing the stump sealed the deal. There are simply too many variables involved at this point to say it's a bad part. In fact, the latter scenario is more likely because you didn't hear/feel anything which means it wasn't a sudden loud noise and immediate loss of front wheel drive, which is more what you'd expect when the shaft completely fails all at once. I've broken drive shafts, axles, differential ring gears, differential pinion gears, and transmission input shafts, under load on heavy equipment, and it's usually really obvious when it happens.

 

[charles todd]

I highly doubt "hopping" occurred in Low 1st gear. L1 will provide the most torque though, which will test all drive line components the most. Tires should have slipped first.

Though the possibility of being cracked prior to the breakage is very possible also. I agree when a shaft is loaded up and goes, there is usually sound and feel!

Good luck Gary, seems like for less than $400 you will be back in business.

CT

 

[Gary Fowler]

I'm curious how you were pulling on the stump, from the rear driving forward or reversing and pulling from the front or loader?

I had the chain hooked to the drawbar and driving forward. I had a disk on the rear that put more weight on the rear tires so the front shouldn't have been heavily loaded. Engine was just at idle and in low gear so there was no jerking on the transmission.

 

[Gary Fowler]

No offense, but you don't have anything to support that....there just isn't any evidence other than "it shouldn't have broken" which isn't certain either.

Driveshafts are rarely covered by warranties, for good reason...they can be broken through "normal" use, and not be faulty. They're intended to fail before expensive parts break, and at only $125 you're pretty lucky.

It's also possible that in the past you did something to damage the shaft (like start a crack), and it didn't fail completely, and pushing the stump sealed the deal. There are simply too many variables involved at this point to say it's a bad part. In fact, the latter scenario is more likely because you didn't hear/feel anything which means it wasn't a sudden loud noise and immediate loss of front wheel drive, which is more what you'd expect when the shaft completely fails all at once. I've broken drive shafts, axles, differential ring gears, differential pinion gears, and transmission input shafts, under load on heavy equipment, and it's usually really obvious when it happens.

I stand by my statement. Any metal if properly heat treated would twist slightly before snapping cleanly like it was saw cut (this according to the dealer) and it broke directly behind the splines. The splines are hardened to prevent stripping but the shaft itself should not be hardened to the extent of the splines.

"Driveshafts are rarely covered by warranties, for good reason...they can be broken through "normal" use, and not be faulty. They're intended to fail before expensive parts break, and at only $125 you're pretty lucky."
So you are saying that it is ok for a driveshaft to break under normal conditions? Do you work for LS by some chance? What is your stance on the 5 year POWERTRAIN WARRANTY. Is not the driveshaft part of the powertrain?

By the way the dealer, SHERIDAN TRACTOR, called this morning and he finally got LS to warranty the shaft and he is contributing the labor to fix it. He agrees that the LS stance is total BS when they say that the driveshaft is not part of the powertrain.

 

[Gary Fowler]

One other tidbit, the warranty guy told my dealer that they have had about 10 front drive shafts break on the P series of tractors that go up to almost 90 HP. Mine is the 70 HP version and all identical components to the 90HP version. I can just see the extra 20 HP wreaking havoc with the shafts that wont stand up to 70 HP. The larger versions also have larger tires, so more traction= more stress on the drive train.

One would think that LS would look at those breakages and fix the issue, but if just rejecting the claim under warranty gets them by then why would they ever even look at the problem. 10 drive shafts breaking on one particular model is not normal and for sure not normal on a tractor that has no added weight to the front end other than the FEL.

Edit: I see that LS has a 7040 version at 97HP now. I don't know if it is identical to the 7010, 7020and 7030 though as I didn't pull up the full spec PDF sheet.

 

[holeycow]

It's good that they are repairing your tractor. They should.

The update may be a complex issue. It's better that the shaft breaks than something else more expensive and difficult to fix. Pretty good engineering really, or at least very close to good engineering.

If you didn't hear a loud "snap!" it had to be already broken before you hooked on the stump, IMO. Those kind of breaks make a sharp, loud sound usually......

I was wondering about the 7040's shaft too.

 

[Gary Fowler]

It's good that they are repairing your tractor. They should.

The update may be a complex issue. It's better that the shaft breaks than something else more expensive and difficult to fix. Pretty good engineering really, or at least very close to good engineering.

If you didn't hear a loud "snap!" it had to be already broken before you hooked on the stump, IMO. Those kind of breaks make a sharp, loud sound usually......

I was wondering about the 7040's shaft too.

I didn't hear a loud snap, but did hear a loud bang when the 3/8 gr. 70 chain broke which I now believe was the chain and the drive shaft going at the same time. I didn't think anything about it possibly breaking the front drive shaft at the time and continued to work on skidding a large log backward about 10 feet with the FEL and it did that without a problem. I only noticed the FWD not working a few days later when I did manage to pull that same stump out with the tractor in 2 WD (4WD but not pulling) and the rear tires were digging in with no assist from the fronts.

I wonder if the sudden reverse unloading cause a snap of the drive shaft. I have seen crane booms do that when a load releases suddenly. Still I don't think a drive shaft designed (supposedly designed) to handle 90 HP engine (P7030) should break with a 70 HP motor when the same components are used in both tractors.

 

[GManBart]

I stand by my statement. Any metal if properly heat treated would twist slightly before snapping cleanly like it was saw cut (this according to the dealer) and it broke directly behind the splines. The splines are hardened to prevent stripping but the shaft itself should not be hardened to the extent of the splines.

That's great, but your statement is still a guess. You haven't seen the shaft in person, haven't done any sort of testing or analysis of the metal, and you still don't know exactly when it broke. That's an awful lot of unknowns to be certain a part was faulty. It's certainly possible, but it's far from a fact. The fact is, that twisting you say should have happened could have happened previously, and that's the reason why it failed this time. Without an analysis of the actual part(s) nobody will ever know for sure what happened.

So you are saying that it is ok for a driveshaft to break under normal conditions? Do you work for LS by some chance? What is your stance on the 5 year POWERTRAIN WARRANTY. Is not the driveshaft part of the power train?

I put quotes around "normal" because you weren't doing something weird, but even doing something "normal" can put an overload on the running gear if a wheel spins, then gains traction, or vice-versa. Abnormal loads can happen while doing "normal" tasks.

Do I work for LS?....seriously, you're going to really ask that? Uh, no, I don't work for any commercial entity.

I think the LS 5 year powertrain warranty is great. That doesn't mean that every single part of the system is covered under all circumstances. Pulling on a stump and a little bit of wheelspin then getting a bite of traction, or losing traction suddenly, could have overloaded the system, and that doesn't mean the part was faulty, and should be covered under warranty. It's great that they're replacing it for you, but that doesn't mean there was a problem with the part, or that the usage was within the design limitations.

Sure, I'd say the drive shaft is part of the powertrain, but so are the wheels, and they don't warranty them if you dent them on a rock.

It's sort of funny that you're talking about a situation where you were pulling a stump hard enough to break the chain, but think it's totally crazy that a driveshaft broke...which could have already been damaged from something previously. 3/8 grade 70 chain has a working load of around 6,600lbs, and a breaking strength of around 26,000lbs, and you broke it. Breaking a driveshaft in that sort of scenario isn't exactly crazy.