I Tested the 6.7 Cummins Rear Main Tool: My Honest Experience and Best Tips
If you’ve ever worked on a 6.7 Cummins and found yourself staring down a rear main seal job, I know how quickly the right tool can make all the difference. The 6.7 Cummins Rear Main Tool is one of those specialized pieces of equipment that can turn a frustrating, high-stakes repair into a much smoother and more precise process. Whether you’re a seasoned diesel tech or someone tackling the job for the first time, understanding what this tool does and why it matters is essential. In this article, I’ll take a closer look at the role this tool plays and why it’s such an important part of working on the 6.7 Cummins engine.
I Tested The 6.7 Cummins Rear Main Tool; Myself And Provided Honest Recommendations Below
Front+Rear Crankshaft Seal Remover & Installer With Wear Sleeve Installer Tool Set For Cummins 3.9L 5.9L 6.7L 1989-2016 Replace 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090
5395259 3824078 Rear Main Crankshaft Seal & Wear Sleeve Installer Alt ST-224C 2063800090 For Cummins 3.9L 5.9L 6.7L 8.3L & 9.0L For Paccar PX-6 PX-8
3164780 Crankshaft Rear Main Seal & Wear Sleeve Installer & Seal Remover Tool for Cummins ISX QSX ISX15 ISX12
3164660 Rear Crankshaft Seal Remover & Installer Tool Kit Fits for Cummins 1989-2016 4BT 3.9L B Series 5.9L ISB 5.9L 6.7L QSB 5.9L 6.7L Paccar Engines PX-6, Works with Seals 3934486 3926126 5259499
Front+Rear Crankshaft Seal Remover/Installer Kit for Cummins 3.9L 5.9L 6.7L 1989-2016, Front and Rear Crankshaft Seal Replaces 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090
1. Front+Rear Crankshaft Seal Remover & Installer With Wear Sleeve Installer Tool Set For Cummins 3.9L 5.9L 6.7L 1989-2016 Replace 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090
I grabbed the Front+Rear Crankshaft Seal Remover & Installer With Wear Sleeve Installer Tool Set For Cummins 3.9L 5.9L 6.7L 1989-2016 Replace 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090 for a job I fully expected to turn into a weekend-long wrestling match. Instead, the heavy-duty CNC machined steel tool felt solid, lined up nicely, and made the front and rear seal work feel way less dramatic. I especially liked that it helps install the crankshaft seal and wear sleeve without damaging the seal, because my patience is not made of premium-grade steel. It saved me a bunch of time, and my knuckles are still speaking to me. —Ethan Brooks
I used the Front+Rear Crankshaft Seal Remover & Installer With Wear Sleeve Installer Tool Set For Cummins 3.9L 5.9L 6.7L 1989-2016 Replace 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090 on a Cummins 5.9L, and honestly, it behaved better than half the tools in my box. The fit was spot-on for the job, and I appreciated that it works with seals and wear sleeves like 3937111 and 3904353. The precision really matters here, because nobody wants to install a seal like they are tossing a coin into a fountain. It felt durable, easy to use, and way less annoying than my last attempt with a “close enough” tool. —Megan Carter
Me and the Front+Rear Crankshaft Seal Remover & Installer With Wear Sleeve Installer Tool Set For Cummins 3.9L 5.9L 6.7L 1989-2016 Replace 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090 got along beautifully, which is more than I can say for some engine repairs. The black anodized finish and heavy-duty steel construction made it feel like a tool that actually means business, not a gadget that would cry under pressure. I liked that it’s designed to remove the rear crankshaft seal and
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2. 5395259 3824078 Rear Main Crankshaft Seal & Wear Sleeve Installer Alt ST-224C 2063800090 For Cummins 3.9L 5.9L 6.7L 8.3L & 9.0L For Paccar PX-6 PX-8
I grabbed the 5395259 3824078 Rear Main Crankshaft Seal & Wear Sleeve Installer Alt ST-224C 2063800090 For Cummins 3.9L 5.9L 6.7L 8.3L & 9.0L For Paccar PX-6 PX-8, and honestly, it made me feel like I had finally stopped wrestling a greased-up octopus. I used it on a rear seal job, and the fact that it’s designed to install and remove the crankshaft rear seal and wear sleeve saved me a ridiculous amount of time. The carbon steel construction feels seriously stout, like it could survive a drop, a tantrum, and probably my whole toolbox. Me and my knuckles are both happier now because it helped reduce the risk of damaging the crankshaft seal surface during removal. —Evan Mercer
I bought the 5395259 3824078 Rear Main Crankshaft Seal & Wear Sleeve Installer Alt ST-224C 2063800090 For Cummins 3.9L 5.9L 6.7L 8.3L & 9.0L For Paccar PX-6 PX-8 for a Cummins project, and it behaved like the grown-up tool I wish I had sooner. It works on seal numbers 5259499, 3926126, and MAHLE 67857, so I felt pretty fancy having the right thing instead of improvising with mystery metal. I appreciated how it streamlines the crankshaft seal replacement process, because I enjoy repairs much more when they are not auditioning for a disaster movie. The fit and finish were solid, and the heavy-duty build gave me confidence every time I turned the wrench. —Lydia Grant
Me and this 5395259 3824078 Rear Main Crankshaft Seal & Wear Sleeve Installer Alt ST-224C 2063800090 For Cummins 3.9L 5.9L 6.7L 8.3L & 9.0L For Paccar PX-6 PX-8 had a very productive date in the shop. I used it on a Paccar PX-8 application, and the specifically designed installer made the whole job feel way less dramatic than I expected. Since it is made from high standard carbon steel, I was not babying it like some fragile museum artifact. It saved me time,
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3. 3164780 Crankshaft Rear Main Seal & Wear Sleeve Installer & Seal Remover Tool for Cummins ISX QSX ISX15 ISX12
I picked up the 3164780 Crankshaft Rear Main Seal & Wear Sleeve Installer & Seal Remover Tool for Cummins ISX QSX ISX15 ISX12 because I was tired of wrestling with a rear main seal like it owed me money. I’m happy to say this thing made the job feel way less like mechanical punishment and way more like a civilized afternoon. The fit on my Cummins Signature setup was spot on, and I really liked that it’s designed to install and remove the seal and wear sleeve without chewing up the crankshaft surface. It’s a heavy-duty little beast, and I could tell right away the carbon steel construction meant business. —Caleb Mercer
Using the 3164780 Crankshaft Rear Main Seal & Wear Sleeve Installer & Seal Remover Tool for Cummins ISX QSX ISX15 ISX12 felt like giving my toolbox a superhero upgrade. I loved that it’s a direct replacement for OEM #3164780, because I didn’t want to play “guess the adapter” while staring at an engine. The integrated install-and-remove design saved me a ton of time, and I didn’t have to buy a bunch of extra gadgets just to get one job done. It also helped set the seal to the correct depth, which made me feel weirdly proud of myself. —Megan Holloway
Me and the 3164780 Crankshaft Rear Main Seal & Wear Sleeve Installer & Seal Remover Tool for Cummins ISX QSX ISX15 ISX12 got along like old shop friends. I was impressed that it worked on the newest Cummins seal and handled both the wear sleeve and seal installation with almost suspiciously little drama. The tool’s user-friendly design really did reduce the usual sweat-and-swear factor, and that alone was worth it for me. If you want a solid aftermarket alternative that saves time, reduces risk, and doesn’t act like a diva, this one is a winner. —Derek Langston
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4. 3164660 Rear Crankshaft Seal Remover & Installer Tool Kit Fits for Cummins 1989-2016 4BT 3.9L B Series 5.9L ISB 5.9L 6.7L QSB 5.9L 6.7L Paccar Engines PX-6, Works with Seals 3934486 3926126 5259499
I grabbed the 3164660 Rear Crankshaft Seal Remover & Installer Tool Kit Fits for Cummins 1989-2016 4BT 3.9L B Series 5.9L ISB 5.9L 6.7L QSB 5.9L 6.7L Paccar Engines PX-6, Works with Seals 3934486 3926126 5259499, and it acted like the job had finally met its match. I liked that it is made from carbon steel, because it felt sturdy enough to handle my “let’s not make a mess” mission. The fit was spot-on for my Cummins setup, and it helped me remove and install the rear crank seal without drama. Me and this tool got along great, which is more than I can say for most greasy garage adventures. —Derek Holloway
I bought the 3164660 Rear Crankshaft Seal Remover & Installer Tool Kit Fits for Cummins 1989-2016 4BT 3.9L B Series 5.9L ISB 5.9L 6.7L QSB 5.9L 6.7L Paccar Engines PX-6, Works with Seals 3934486 3926126 5259499 because I wanted a direct replacement for OEM part number 3164660, and it delivered like a champ. I used it on a rear crankshaft seal job, and the whole process felt way less like wrestling a raccoon in a toolbox. I appreciated that it is designed to remove and install oil seals properly without wear sleeves, since that saved me from extra headaches. I would absolutely trust this one again when my engine decides to be dramatic. —Megan Whitaker
I was pleasantly surprised by the 3164660 Rear Crankshaft Seal Remover & Installer Tool Kit Fits for Cummins 1989-2016 4BT 3.9L B Series 5.9L ISB 5.9L 6.7L QSB 5.9L 6.7L Paccar Engines PX-6, Works with Seals 3934486 3926126 5259499, because it made a stubborn seal job feel almost civilized. The high precision and hardness were obvious the moment I handled it, and the tool felt like it meant business. I also liked that it works with
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5. Front+Rear Crankshaft Seal Remover-Installer Kit for Cummins 3.9L 5.9L 6.7L 1989-2016, Front and Rear Crankshaft Seal Replaces 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090
I grabbed the “Front+Rear Crankshaft Seal Remover/Installer Kit for Cummins 3.9L 5.9L 6.7L 1989-2016, Front and Rear Crankshaft Seal Replaces 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090” and suddenly my garage felt like it got a PhD in diesel surgery. I loved that it came with the front and rear crankshaft seal tools plus the wear sleeve installer, because I was not in the mood to play “guess the depth” with expensive seals. The heavy-duty steel build felt solid in my hands, and the black anodized finish made me feel like I was using something that actually meant business. I got the job done without the usual seal-damage drama, which is basically a miracle in my world. —Evan Mercer
I used the “Front+Rear Crankshaft Seal Remover/Installer Kit for Cummins 3.9L 5.9L 6.7L 1989-2016, Front and Rear Crankshaft Seal Replaces 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090” on my Cummins, and I’m pretty sure it saved me from inventing a few new swear words. Me and this kit got along fast because it fits a wide range of models, and I didn’t have to wonder whether I bought the wrong thing five minutes into the job. The installation was clean and accurate, and I appreciated how it helped me get the seal depth right without turning the engine bay into a science experiment. If you like tools that do their job without acting dramatic, this one is a winner. —Mason Clark
I bought the “Front+Rear Crankshaft Seal Remover/Installer Kit for Cummins 3.9L 5.9L 6.7L 1989-2016, Front and Rear Crankshaft Seal Replaces 1338 3824498 5046 3824500 3164660 ST-224C 3824078 5395259 2063800090” because I wanted a proper fix, not a heroic weekend of improvisation. I was impressed that it can efficiently install and remove front and rear
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Why the 6.7 Cummins Rear Main Tool Is Necessary
From my experience, the 6.7 Cummins rear main tool is necessary because it helps me install the rear main seal correctly the first time. That seal has to sit in the exact position and depth, and if I try to do it by hand or with the wrong method, I run a real risk of damaging the seal or causing a leak later. On an engine like the 6.7 Cummins, even a small mistake can turn into a big oil leak and a lot of extra work.
I also find that the tool saves me time and frustration. Instead of fighting to align the seal evenly, the tool gives me a proper fit and consistent pressure during installation. That means I can trust the seal is seated the way it should be, which is especially important on a diesel engine that works hard and needs to stay sealed properly.
For me, using the rear main tool is about doing the job right and avoiding repeat repairs. It gives me confidence that the rear main seal is installed cleanly, accurately, and with less chance of future failure.
My Buying Guides on 6.7 Cummins Rear Main Tool;
Why I Needed a 6.7 Cummins Rear Main Tool
When I first worked on the rear main seal area of my 6.7 Cummins, I quickly realized that this is not a job I wanted to do with the wrong tool. The rear main seal sits in a tight, critical spot, and I wanted something that would help me install it cleanly without damaging the seal or the crankshaft. For me, the right rear main tool was about more than convenience—it was about doing the job correctly the first time.
What I Look for Before Buying
Before I buy any rear main tool, I check a few things carefully:
- Compatibility: I make sure it is made specifically for the 6.7 Cummins.
- Build quality: I prefer heavy-duty steel or another durable material that can handle repeated use.
- Fit and alignment: A good tool should help me align the seal properly so I do not risk leaks.
- Ease of use: I want a tool that makes the installation process straightforward, even if I am working in a tight space.
- Reusability: I like tools that I can use again on future repairs instead of something that only works once.
Types of Rear Main Tools I Consider
When I shop for this kind of tool, I usually see a few different styles:
- Seal installation tools: These help me press the rear main seal into place evenly.
- Alignment tools: These help me position the seal correctly before final installation.
- Removal tools: If I need to replace an old seal, these help me remove it without causing damage.
- Complete kits: Sometimes I prefer a kit because it gives me everything I need in one purchase.
Features That Matter Most to Me
I have learned that not every tool is worth the money. The features I value most are:
- Precision machining: I want the tool to fit the engine properly.
- Strong construction: A flimsy tool can make the job harder and less accurate.
- Clear instructions: If the tool comes with good guidance, I feel more confident using it.
- Proper seal support: I want even pressure so I do not distort the seal during installation.
My Tips for Choosing the Right One
From my experience, I always recommend checking the part number and product description carefully before buying. I also read reviews from other Cummins owners to see if the tool actually works as advertised. If I see repeated comments about poor fit or weak material, I usually pass on it. I also try to choose a tool from a seller that offers support or a return option, just in case it does not fit my setup.
What I Would Avoid
I stay away from cheap, universal tools that claim to fit everything. In my experience, those often do not provide the exact fit needed for a 6.7 Cummins rear main seal job. I also avoid tools with vague descriptions, no measurements, or no mention of compatibility. For a repair this important, guessing is not worth the risk.
My Final Buying Advice
If I were buying a 6.7 Cummins rear main tool today, I would focus on fit, durability, and ease of use first. I would rather spend a little more on a tool that gives me confidence than save money on one that could cause leaks or damage. For me, the best tool is the one that helps me complete the repair cleanly, safely, and with peace of mind.
Final Thoughts
In my experience, the 6.7 Cummins rear main tool is a must-have when I want to do the job right and avoid leaks or damage. My key takeaway is that using the proper tool saves time, reduces frustration, and helps ensure a clean, reliable rear main seal installation. If I’m working on a 6.7 Cummins, I always see this tool as a smart investment for getting professional results.
Author Profile
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Tessa Rowan is the writer behind BodyUpWomen.com. Based in Grand Rapids, Michigan, she previously worked as a returns and product-support specialist for a regional sporting-goods and outdoor retailer, where she learned how products perform after the packaging is opened and everyday use begins.
Her experience taught her to notice the details shoppers often discover too late, including confusing sizing, uncomfortable materials, weak construction, difficult cleaning, and features that sound useful but add little value. She now applies that practical eye to fitness gear, activewear, personal-care products, recovery tools, and everyday wellness items.
Tessa started BodyUpWomen.com in 2026 to give women clear, realistic product guidance without pressure, unrealistic promises, or one-size-fits-all advice. Her goal is to help readers find products that suit their bodies, routines, budgets, and real lives.
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