Buying Used - Defender Pro XT HD10

[CampHamp]

Hey folks.

I've verbally landed a 2020 Defender Pro XT HD10 which has only 34 miles and I pick it up on Tuesday. It comes with a Boss plow with hydraulic lift and direction. $19K. I'm looking forward to discussing these machines with you all!

I plow a few driveways and I haul lots of firewood for heating and making maple syrup. It'll be 100% a work machine.

I'm replacing my Yamaha Rhino 660 (2004) that still runs fine. This will be a whole new experience in terms of size and power. The bed is up high - a bit of tough lift to fill it up. I wonder if I will still tow a trailer for wood so I can work down low. I may need to widen some trails. I do some gravel work for a long driveway, so tractor dumping into the bed will be great. We'll see... I didn't know how valuable a tractor would be until after I got it and this may be the same deal.

I may love it, but maybe it will be too big for forest work. I figure that since I got a decent price I should be able to sell if need be.

It will be a 'no warranty' purchase and I want to be careful it isn't a lemon. I'm thinking that I should drive it around in high, low, test the drive modes and all the 4WD/diff lock options. Probably I'll check oil level to ensure they didn't neglect it, run the plow movements and check tires for repair.

It would be great to hear from you all, with Defender experience, about what other things that I should look and listen for before I hand over the check.

Thanks, in advance for any info you might offer!

[Andystoy19]

If it only has 34 miles you should be good to go, but if you have a concern have a dealer check for any set codes like oil pressure, engine over heat  etc. If you can run it down the road take it up to a good speed to see if anything shows up. Enjoy the new purchase and yes it will tow your trailer so you can make less trips.🙂

[CampHamp]

Thanks for your reply. The seller agreed to allow for a 1-week trial, where I can return it if there is a major ($1K+) issue discovered.

Now it's time to shop for doors and windshields... maybe a heater!

[CampHamp]

I got the Defender home. Rides so much smoother than my tiny Rhino. The Boss plow is serious and like the hydraulic up/down rather than winch.

There is a small(?) problem that I only noticed after I got it home: a rattle/buzz sound coming from the front right wheel well when I let go of gas around 14mph. Happens pretty consistently (50% of the time).

I've found others on the forum describing what could be a similar issue, mostly written-off as "harmonics", but one person ended up needing a new front diff. Yikes! Another wrencher bought new CV shafts and thought it helped.

Here is a very short video that needs max volume. You'll hear the sound when I let the gas off at 14mph.

It seems somewhat minor, because it's a short noise, but it's loud enough to think each time that "something is wrong". I could return it, but I don't want to if it won't turn into a big fix.

 

[Steelslinger]

Try changing the oil in the front diff. Look to see if there is anything abnormal in the oil (excessive shavings, chunks, water, etc).

[CampHamp]

 

Thanks Steelslinger, great idea!

Unfortunately, the plow plate on the front doesn't have a hole to drain the front diff! I have the plow attached for a storm tomorrow and then there will be a mess of bolts, the winch fair-lead, etc. Anyway, a royal PITA to properly drain that oil.

So for today, I decided to suck some oil out from the fill hole just to be able to do an initial inspection. I could only get 70% out that way and I assume any big pieces would be at the bottom and out of reach.

I took a video of the extracted oil (far below). There is a dust storm of metal particles, but is this OK to see after an engine break-in (now at 50mi)? I'd appreciate your thoughts about if this might indicate that the diff is damaged...

Another thing, the oil level was low -- down about 1/2 inch. After I filled it up all the way, I test rode it and it stopped making the rattling grumble sound! I'll test more tomorrow.

Here's what the oil looked like:

https://youtube.com/shorts/Y7VnkojzUmA?feature=share 

 

 

[Steelslinger]

Could have been low oil, old oil seems a little too metallic for that few miles. I changed mine at 1200 miles and can't remember if it was that shiny.

I'd get it changed asap, run it for the winter and then check it again in the spring.

Stupid that the mount doesn't have a oil drain hole in it. First thing I'd be fixing. 

[CampHamp]

I drove it around for a longer test today and I couldn't make that rattling sound at all. So, the cause was either that the front diff oil level was low or the oil that was in there was too contaminated. Psyched to have this resolved!

Yes, I will take off that mount plate (a total BOSS Plow FAIL) and drill a hole before it goes back on. I'll need to get a 1" carbide bit before I get started.

Edited December 18, 2021 by CampHamp

[CampHamp]

I changed-out the front diff oil completely last night and drilled a hole in the plow mount plate for next time. There were no pieces of metal, so nothing seems busted in there.

The interesting thing is the chattering sound returned after the oil change! I checked the level again this morning and it is completely full.

When I got this chattering to stop last time, I thought it was just that it was that the level was low or maybe it was because I got much of the old oil out (I could only replace 70% of the old on that first change using a suction tube).

I have another theory, now that these first two ideas were obviously wrong! I didn't mention, but I used the "wrong oil" last time, it was Lucas 80W90 Non-Synthetic. The chattering stopped with that stuff mixed in, but has returned now, running with Valvoline 75W90 Synthetic.

I wouldn't have ever guessed that this slight oil type difference could have an effect.

I'm tempted to swap in some Lucas 80W90 Non-Synth again, but think that I will first try using Genuine Ford Fluid XL-3 Friction Modifier Additive - 4 oz after learning about this recommendation on this forum (albeit second hand) from a Can Am technician.

If anyone thinks that using a 50/50 mix of 80W90 Non-Syn and 75W90 Syn (or even using all 80W90) would be less risky than putting in this additive (1 oz?), then let me know because I'm shooting from the hip anyway...

 

Edited December 21, 2021 by CampHamp

[CampHamp]

The Friction Modifier did not help with the chatter noise. There's still a "duck quack" sound when I decelerate through 14mph (it's speed-related and not RPM -- happens in H, L, 4WD/2WD).

This video suggests that the "loss of pinion bearing preload" can cause this type of chattering sound when decelerating. I'm not sure if this issue requires immediate repair.

It looks hard to remove the front diff, but I suspect it's the next step. Wish I had a proper lift!

[Andystoy19]

Check out the builds section if you want to remove the diff, its not bad at all if you don't have the plow on. The stock diff has a part called viscolok that senses the difference in speed between the front axles and applies more power to the front wheel that is not spinning. It is enclosed and has its own viscous oil inside. I replaced my viscolok unit with a pin locker setup because I wanted to be able to lock the front axles together in deep mudholes, steep climbs, snow etc.

The friction modifier should have little to no effect on the front diff since there are no clutches or plates like those in a vehicle rear diff. I don't know if there is a description in the builds section on how to adjust the lash with spacers, shims which you should be able to purchase from your dealer, if not check out the online videos from pinlocker (SATV) and halo locker for some pointers.

You can lift the vehicle with a floor jack or hydraulic jack and block up the front end under the skid plate so you can remove the front wheels and axles etc. no need for a lift.🙂

[CampHamp]

I saw your pin-locker post. Thanks for pointing me to the builds section.

I could probably get my diff out in a few hours (I'd need to take off the plow mount and winch again!)

However, don't I need a special torque wrench to measure the preload and another special tool to measure the play in the main pinion gear? Are there cheaper ways to get those measurements? Otherwise, I'm not sure I'd be able to do anything useful once I got it out, beyond a basic inspection of the gears and ware patterns.

My current plan is to use the Defender to plow this winter unless it gets any worse. When I can spare some downtime in the spring (after maple season), I'll rip it out, look for any breaks or bad ware patterns then bring the diff to a shop for an expert diagnosis. I doubt this needs to be a Can Am person, but will try there first.

[Andystoy19]

You should be good until spring, check out one of the videos for tools that you might require but if my memory is correct I think all that is necessary is a dial micrometer?🤨