Welcome to ZK MasterTech.
Follow Master John Deere Ag Technician Zeth Key as he takes you behind the scenes of diagnosing, repairing, and rebuilding some of the most advanced farm equipment in the world. From massive 9RX tractors to S-Series combines, this channel shows the real work required to keep modern agriculture moving.
Zeth is a 2007 Automotive Graduate of WyoTech in Laramie, Wyoming and a 2023 WyoTech Hall of Fame Inductee. He currently works for Sloan Implement in Atwood, Illinois, bringing over 16 years of experience servicing and repairing John Deere equipment across central Illinois.
ZK MasterTech gives viewers an inside look at the technical side of agriculture — real diagnostics, field service calls, major repairs, and the problem-solving it takes to keep farmers running.
If you enjoy seeing big iron torn down, diagnosed, and put back to work, you’re in the right place.
Subscribe and follow along as we keep that green iron moving! 🔧💚
ZK MasterTech
Rain’s got everything shut down… so we’re bringing the shop to you today.
New video drops at 2PM 👇
We finally tear into the 9RX 640 transmission and see the damage we’ve been waiting on. I go through it with Paul and we break down what failed and what we’re dealing with.
Ben rolls in a brand new 412R sprayer and we go over all the tech during pre-delivery.
I’ve also got an X9 1100 combine in the shop getting a full inspection to be field ready, plus updates on the storm-damaged 9360R and 9530T.
We check out the Milwaukee M18 handheld vacuum, put the Shop Dog CBX to work on the X9, and wrap it up with a look at a brand new Chevy 6500 4x4 service truck with a Knapheide crane body 👀🔥
No service calls… but plenty going on in the shop.
Video drops at 2PM — don’t miss this one.
5 hours ago | [YT] | 175
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ZK MasterTech
Spring Service Calls are BACK with EPISODE 3 and this one gets deep 👀
We went to check on LT. DAN’s brother — a 9RX 640 with a 15.0L Cummins that cranks but won’t start… and it turned into a full starting system deep dive. Bad starter, relays on order, and breaking down the entire circuit so YOU know what actually happens when one won’t fire.
Then we roll into more service calls — including a 9510R that absolutely ate up some time 🔧
And the big question…
💸 Will $24,000 worth of injectors finally fix it?
Go watch it now and tell me what YOU think is really going on 👇
6 Breakdowns… Oil in coolant, broken gears and a major injector job
https://youtu.be/GF8UL61ynSU
And as always — keep that green iron moving!
6 days ago | [YT] | 348
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ZK MasterTech
Spring Service Calls Episode 2 is LIVE 🔥
This one starts with a storm launching a shed door into TWO tractors… yeah, it’s as bad as it sounds.
6 breakdowns this week—wiring issues, fuel system problems, and a few curveballs that didn’t go as planned.
Go check it out and let me know what you think 👇
https://youtu.be/eZAfebdxtEg
And as always — keep that green iron moving! 💪
1 week ago | [YT] | 350
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ZK MasterTech
Spring 26’ Service Calls are BACK and Episode 1 is LIVE 🔧🌱
https://youtu.be/SZyg21FBHnk
We’re kicking it off with something you don’t see every day… a RARE John Deere 8560 US NAVY tractor — there’s only TWO in the world and this one is serial number 1 👀
Then it’s straight into multiple service calls and breakdowns you don’t want to miss.
If you haven’t watched it yet, go check it out now and let me know what you think!
More service calls coming soon… let’s keep that green iron moving 😤
2 weeks ago | [YT] | 248
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ZK MasterTech
This one is taking OFF right now…
Spring service calls are no joke 😅
If you haven’t seen it yet—6 breakdowns in one day + one of the RAREST John Deere tractors ever built. Watch it now!
https://youtu.be/SZyg21FBHnk
2 weeks ago | [YT] | 363
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ZK MasterTech
Starting Spring ’26 service calls with a BANG 💥
Can anybody guess what John Deere tractor this is? 👀
HINT: there are only 2 in the world…
New video drops Saturday at 3 PM.
One RARE tractor.
6 breakdowns.
You do NOT want to miss this one.
3 weeks ago | [YT] | 327
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ZK MasterTech
Greta’s story is finally all in one place…
This John Deere 9100 started as a RUNAWAY… screaming up to 3,000 RPM — then turned into a no-start, a start-and-die, and one of the most drawn-out diagnostic fights I’ve dealt with.
This one tested everything.
The FULL Greta story drops tomorrow at 3:00 PM — start to finish, no jumping between videos.
If you’ve ever chased an issue that made zero sense… this one’s for you.
Be there 👊
Also, Spring 26' Service calls series will be coming soon! Who's pumped for that?
4 weeks ago | [YT] | 403
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ZK MasterTech
The FULL Lt. Dan story drops today at 3 PM.
This is the entire 9RX 640 saga — from catastrophic rear axle failure to complete rebuild — all packed into one 45-minute episode.
Zero lube pressure. Destroyed pinion gears. Full teardown. Precision rebuild. First fire-up.
And here’s the cool part — I kept this video under 60 minutes so it will be available in 22 languages. Right now they’re all processing.
Set a reminder — you don’t want to miss this one.
1 month ago | [YT] | 361
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ZK MasterTech
What was your favorite moment in the finale of LT. DAN the 9RX?
1 month ago | [YT] | 106
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ZK MasterTech
LT. DAN IS BACK. 💪
The 9RX 640 is finally back together — and with the wide stance tracks installed, this thing looks meaner and tougher than ever.
This wasn’t just a repair… this was a full comeback. And you already know we don’t do anything halfway around here.
Video drops TODAY at 3pm.
1 month ago | [YT] | 274
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