Case 480FLL 4x4 front wheels turn slower than back wheels in 4x4

[Noland]

Hi folks,

I’ve got a Case 480FLL 4x4 that has a drivetrain problem. When the machine is in 2 wheel drive it pulls fine no problems. The machine rolls smoothly and has good power at the wheels. When you put it in 4 wheel drive the machine literally comes to a stop if you’re rolling slowly. The front wheels turn slower than the back wheels and bogs the motor down like you’re holding the brakes but you’re not. The front tires leave an impression in the ground because they’re not turning in sync with the back tires.

History:
I’ve had the tractor for about 5yrs and it never had any problems. A few months ago the transfer case froze up and stripped the gears inside the transfer case. I believe this happened because my employee drove the tractor several miles on the road in 4 wheel drive and locked it up. We installed a salvaged transfer case and then noticed the problem with wheels turning at different spends. The salvaged transfer case has the exact same numbers as the old one.

Troubleshooting:
We’ve taking the covers off the transaxle and there’s no gears stripped or damaged.

All gears have slack and turn freely. The driveshaft from the transmission to the transaxle has slack and backlash. The gears in the transfer case have slack and backlash as well. The driveshaft from the transfer case to the front axle also has backlash. There’s no grinding noise like gears stripped out somewhere else.

We put the machine on jack stands to get the tires off the ground. Put the machine in 4 wheel drive and all wheels turn freely and there’s no noise or anything noticeable.

We haven’t taken the front axle apart but we have checked for metal in the oil and there was none. With the machine in neutral the front wheels turn freely and no noise coming from the axle.

Any help would be greatly appreciated!

Thanks in advance!
Brian

 

[woodfirst]

Ruling out the obvious. Are you sure you have the correct tire radius on front and back. Are they stock/original?
Could also be the reason for the 1st transfer case failure

 

[Tinkerer]

Hi folks,

We installed a salvaged transfer case and then noticed the problem with wheels turning at different spends. The salvaged transfer case has the exact same numbers as the old one.
Brian

The first thing that occurs to me is that although the transfer case has the same number as your original it does not have the same ring and pinion gears or planetary gears in it.
The 480 you have was available with two different planetary gear sets.
list #6-34 and 6-35A -- go to the parts book here ---https://www.mycnhistore.com/us/en/casece/light-equipment/loader-backhoes/f/case-construction-king-loader-backhoe/power-train/cn/AECF6496-EFBE-E111-9FCE-005056875BD6_06_POWER_TRAIN

 

[Tinkerer]

I hope you still have access to your old case.
If you do, dis-mantel it and determine what is different from the replacement.
It should be quite obvious.

 

[Noland]

Ruling out the obvious. Are you sure you have the correct tire radius on front and back. Are they stock/original?
Could also be the reason for the 1st transfer case failure

 

[Noland]

Ruling out the obvious. Are you sure you have the correct tire radius on front and back. Are they stock/original?
Could also be the reason for the 1st transfer case failure

Woodfirst: The tires have not been changed and it didn't have problem until the transfer case was replaced.

 

[Noland]

I hope you still have access to your old case.
If you do, dis-mantel it and determine what is different from the replacement.
It should be quite obvious.

Tinkerer: We compared the old to the new and they both looked the same.

 

[Noland]

The first thing that occurs to me is that although the transfer case has the same number as your original it does not have the same ring and pinion gears or planetary gears in it.
The 480 you have was available with two different planetary gear sets.
list #6-34 and 6-35A -- go to the parts book here ---https://www.mycnhistore.com/us/en/casece/light-equipment/loader-backhoes/f/case-construction-king-loader-backhoe/power-train/cn/AECF6496-EFBE-E111-9FCE-005056875BD6_06_POWER_TRAIN

Tinkerer:
Which planetary gear set are you referring to?
Can you tell me what section of the parts book the gear set is in?
If the problem is a wrong gear it would have to be in transfer case, correct?

 

[Tinkerer]

I'm not saying your problem is with the planetary's . But it is where I would be looking first.
Open the link I posted and you will see both Carraro Front drive axles.
I think they were used in some of the 580 series tractors also.
You can easily see the differences in these two images.
Especially the gear part numbers.

 

[Noland]

Tinkerer: We removed the front axle and inspected planetary gears in both sides and the chunk in the front end. Everything was intact and squeaky clean. I spoke to the parts guy and he said Case used the same set of gears on the transfer case and the part number on the old transfer case matches exactly with part number on the new transfer. The gears in the new transfer case spin as smooth as silk. I don’t have much hair left. At this point I fell like it’s got to be something simple. If there’s nothing wrong with front end, nothing wrong with the gears in the transaxle and nothing wrong with the transfer case then there’s nothing else it can be. The manual says something about an adjusting cover on the transfer case. There’s not much to adjust but could that have anything to do with it? I don’t have much hair left lol

 

[Tinkerer]

One of the pros will have to help you, Noland.
It is beyond my skills to go any further with your problem.
All I can say is it appears to me there is a difference in the gear ratios in your replacement and the original.
I don't think it is possible that the front drive shaft is turning slower than it was before the roading disaster.

 

[Tags]

Tinkerer is 100% right, the only way to know for sure is to take the transfer case apart and see if all the gears are the same part numbers as your old transfer case. Better yet, if you had the old transfer case take that apart to and see if everything matches up with the new one you got.

 

[Tinkerer]

Exactly, Tags,
There is no way to be 100% certain someone hasn't had either one or both of Noland's axles apart before and changed parts in them.

 

[Swetz]

Noland,

Like Tinkerer, I am no expert on this specific machine, however, this tells the story:

We installed a salvaged transfer case and then noticed the problem with wheels turning at different spends

It was not like that before, the only thing that changed is the transfer case, it must be in the new case. Just because the numbers on the case match does not mean that a previous owner did not swap out gears. To me, you need to verify the gears (gear ratios) are exactly the same.

 

[Swetz]

Exactly, Tags,
There is no way to be 100% certain someone hasn't had either one or both of Noland's axles apart before and changed parts in them.

We were typing the same thing at the same time...LOL

 

[Tinkerer]

LOL, only louder !

 

[Vetech63]

Count me in on the gear ratios being different. Are you getting these numbers on the case itself? I'm wondering if your looking at the casting number which may be the same on both cases.....where the gear ratio may be different. The gear ratio will be difficult to see by eye. The best way to get close to determining the difference is to spin the input shaft by hand and count the revolutions at the output shaft per 1 turn of the input shaft. Do this on both and see if they match.

 

[hookedondiesel]

No expert on this, but if the diff's are ok and the transfer case is the same and look's good, the only thing left would be the transmission.

 

[heymccall]

You can run 5.13 and 4.88 gearsets on a Mack RD688S w/44k rears for 18k miles and only put in 3 power dividers, to replace the scrambled power dividers.