Differential Oil Change Frequency

[meant2shop]

I have a 2006 Fleet Pace Arrow 37C with 21,500 miles on odometer. It has a Freightliner engine.

Getting ready today to take it in for a routine engine oil change.

How often should the rear differential get an oil change? Is it due for one now or too soon, given the low mileage?

How do I know if there’s a leak in the rear differential? Not saying there is, and no evidence, but was advised there was a leak by an RV and Truck repair place we took the rig to about 4 yrs ago for an oil change, if I recall.
We were not happy with their service for other reasons, and felt they were trying to pad our bill with unneeded repairs, so we chose to dismiss their diagnosis of the leaking differential.

Haven’t driven the rig more than a few miles, just for propane, gas, maintenance/repair, in approx. 24 months, since my husband got cancer and subsequently died. I do routinely start the engine and generator weekly and let then run.

Would appreciate response this AM if possible.

Thank you.
Meant2shop
Merlin OR

[Mr_D]

Freightliner doesn't make engines.
Mine is 100,000 miles. So far I'm at 52,000. Was at a Cummins shop for the last month and asked them to check it. In fact I just (within the last hour) sent them another email asking for verification of the service being done.

[grindstone01]

I always figured to change diff oil at 50k miles or 5 years, which ever come first. If you have a diff leak, the leak area will be wet with oil, also check the diff level before you drain it to be sure it was full and not leaking. Make sure your new diff oil is the right oil weight/spec for your vehicle.
Changing fluids too early in a vehicle is usually not a problem, however, using fluid beyond it's life can be fatal and expensive to a vehicle. Vehicle fluids are cheap compared to replacing parts and I trend to error on the safe fluid side.
Also, have your power steering and coolant fluid checked or changed. I assume you have air brakes w/no brake fluid.

[Jim_HiTek]

The differential can leak at the shafts that go from the pumpkin (that big roundish thing attached to the engine) to the drive wheels. The oil in the pumpkin can leak by one of several seals there at the pumpkin or can travel down the cover tubes and can leak at the wheels if there's a bad seal there.

I had a diesel pusher on a Freightliner chassis and one time in Mexico I hit a speed bump at 55 MPH which caused a leak from one of the drive axles. The metal tube that surrounds the axle had developed a tiny gap because of hitting the speed bump and it leaked from there.

I used a tube of Red Permatex to seal it up. But before that, I'd have to top off the pumpkin with the heavy weight oil every 10,000 miles.

I would want to look around under the chassis myself before I took a shops word for what was leaking. Take it to a different shop and have them look at it. Have them show you and climb under there yourself. If it's leaking around a drive wheel shaft though, that can ruin a brake pad and that's no joking matter. That's expensive but it's usually fixed, not just maintained, and you don't worry about it again.

Before you have work done, always check RVServiceReviews.com so see if there's any reviews of shops in your area. BTW, I usually lean towards calling a mobile tech to come out and check stuff like that for me. I tend to trust them far more than dealers.

[Crasher]

FWIW, it's not a good idea to start the engine unless you are going to drive it and warm it up for 20-30 miles. If you want to start the generator, put a load on it like the air conditioners in warm weather or the heat pump in cool weather. I do not start either of them unless I am going to use them. As for the differential oil, it's early mile wise to change it, however, at 13 years old, it could be beneficial to get it changed and start with fresh clean oil.

[Domo]

If you have a freightliner CHASSIS - you can simply call them with the last six digits of your VIN and they'll tell you what it needs regarding changing.

1 800 FTL-HELP

Pretty sure they're 24/7 and always very helpful and courteous.

[Skiddy]

Originally Posted by Domo

1 800 FTL-HELP

Pretty sure they're 24/7 and always very helpful and courteous.

yes I have called them a couple times way after normal business hours

[C.Martin]

Originally Posted by Domo

If you have a freightliner CHASSIS - you can simply call them with the last six digits of your VIN and they'll tell you what it needs regarding changing.

1 800 FTL-HELP

Pretty sure they're 24/7 and always very helpful and courteous.

+1

The service interval should be in the Freightliner manual that comes with the coach. But Freightliner 24/7 can look it up for you.

The axle manufacturer probably sets the change interval. My chassis specifies annually for the drive axle if using dino oil...or every three years if using synthetic that meets Mercedes Benz specs...such as Mobil Delvac 1. I use the synthetic.

[meant2shop]

Originally Posted by meant2shop

I have a 2006 Fleet Pace Arrow 37C with 21,500 miles on odometer. It has a Freightliner engine.

Getting ready today to take it in for a routine engine oil change.

How often should the rear differential get an oil change? Is it due for one now or too soon, given the low mileage?

How do I know if there’s a leak in the rear differential? Not saying there is, and no evidence, but was advised there was a leak by an RV and Truck repair place we took the rig to about 4 yrs ago for an oil change, if I recall.
We were not happy with their service for other reasons, and felt they were trying to pad our bill with unneeded repairs, so we chose to dismiss their diagnosis of the leaking differential.

Haven’t driven the rig more than a few miles, just for propane, gas, maintenance/repair, in approx. 24 months, since my husband got cancer and subsequently died. I do routinely start the engine and generator weekly and let then run.

Would appreciate response this AM if possible.

Thank you.
Meant2shop
Merlin OR

Thanks for everyone’s response. Went ahead and had the differential oil replaced today, as the oil was dark brown color.

Guess I wasn’t entirely clear in my original post, based on some replies received here.

I’m a widow. My husband took care of all these type of things so I’m pretty clueless. I had to read the owner’s manual today to find out what grade/type engine oil to use in the oil change so I could relay this info to the tech. He suggested synthetic vs regular oil, but manual said to only use synthetic if my rig would be in extremely cold temps, like 0 or below, which isn’t the case here in So OR, this time of year or pretty much ever!

Didn’t know the engine hood had to be opened with a special key either, but luckily located it in the key locker.

As far as getting/crawling under my rig for any kind of inspection of differential seals or anything else - that will never happen. I’ll leave that up to someone who’s Qualified, knows what to look for and what they’re looking at, and very agile - not me, lol. But good advice all around, even if a lot of it is beyond my limited scope of comprehension as it relates to RVs.

Thanks to all,
Meant2shop
Merlin OR
2006 Fleetwood Pace Arrow 37C

[barmcd]

The manual for Monaco says 3 years or 100,000 miles which seems like a good rule of thumb if you don't have other information from your manufacturer.

[hrw]

I would guess 100,000 miles or ten years....? If you don't drive 10,000 miles a year that rear end oil will last a long time. Some trucks go much longer than that before they change that oil, if ever...?

[BigLar368]

Originally Posted by hrw

I would guess 100,000 miles or ten years....? If you don't drive 10,000 miles a year that rear end oil will last a long time. Some trucks go much longer than that before they change that oil, if ever...?

This is exactly what I was thinking. I worked as a heavy equipment mechanic for years at a local municipality and changing the differential oil (rear end/gear lube) was never on the maintenance agenda. We had old fire trucks that were 30+ years old that had never had any gear oil changes and never had a problem. Only checked every so often during old changes. If there is not a visual leak then more than likely it's full. It never hurts to check it though. I checked mine last year and it was completely full. It has 60K miles on the clock and its 15 years old and I have no plans on changing it anytime soon or ever at all.

With all that being said we did have a few differential failures in the years I worked there but it was always due to oil leaks. Being on top of visual inspection for leaks is probably the most important aspect when it comes to this subject.