'05 LJ Rubicon Flywheel Questions

g.hayduke

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Hey gang. I'm replacing my clutch and ready to start putting things back together ... maybe. I'm not sure about my flywheel condition. I'm also curious if '05 4.0 models had the iconic convex flywheel. Mine appears to be flat.

When I bought this Jeep it had about 80K miles on it. All the parts I removed appear to be original. The clutch disk & pp had Sachs brand marks on them. The rim of the flywheel has the mark "DA 38382". I could not find any flywheels with that part number but again, I suspect this is an original flywheel. When I put a steel straight edge on it, it appears to be perfectly flat. It also has some hot spots.

So my questions:
  • Does this look like an original flywheel?
  • Did '05 LJRs have a convex flywheel? Apparently '05 - '06 have a different flywheel from the earlier years but it might just be the ring for the CPS that's different.
  • If it came with a flat flywheel, is there any harm in having this one resurfaced?
  • Based on the pictures, should this flywheel be resurfaced/replaced?
  • Is the LUK LFW484 a suitable replacement (flat or convex, whichever is correct)?

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20200904_114843.jpg


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Straight from the '05 service manual: "Flywheel machining is not recommended. The flywheel clutch surface is machined to a unique contour and machining will negate this feature. Minor flywheel scoring can be cleaned up by hand with 180 grit emery or with surface grinding equipment. Remove only enough material to reduce scoring (approximately 0.001 - 0.003 in.). Heavy stock removal is not recommended. Replace the flywheel if scoring is severe and deeper than 0.076 mm (0.003 in.). Excessive stock removal can result in flywheel cracking or warpage after installation; it can also weaken the flywheel and interfere with proper clutch release."
 
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The convex shape of the flywheel is very minor, and is very difficult to see without a gauge.

I can’t tell for sure, but this looks like a factory style flywheel. Personally, I would buff it out and keep using it, unless there are any gouges or other significant surface discontinuities.

The 91-04 and 05-06 flywheel are similar, but not compatible. The 91-04 has two spots for the crankshaft position sensor; the 05-06 has three.

I imagine most aftermarket flywheels are probably fine. I went with the Centerforce 700479 because it is significantly heavier than stock, but it’s not necessary for most people. The Luk is probably fine.

If you replace the flywheel, you are supposed to replace the bolts. ARP makes a bolt kit that is stronger than factory. You cannot use standard bolts; they must be flywheel bolts.
 
So my questions:
  • Does this look like an original flywheel? It does
  • Did '05 LJRs have a convex flywheel? Yes
  • If it came with a flat flywheel, is there any harm in having this one resurfaced? It didn't so Yes!
  • Based on the pictures, should this flywheel be resurfaced/replaced? Neither, clean it up with 180 grit emery paper
  • Is the LUK LFW484 a suitable replacement (flat or convex, whichever is correct)? Yes
See above^^
 
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Straight from the '05 service manual: "Flywheel machining is not recommended. The flywheel clutch surface is machined to a unique contour and machining will negate this feature. Minor flywheel scoring can be cleaned up by hand with 180 grit emery or with surface grinding equipment. Remove only enough material to reduce scoring (approximately 0.001 - 0.003 in.). Heavy stock removal is not recommended. Replace the flywheel if scoring is severe and deeper than 0.076 mm (0.003 in.). Excessive stock removal can result in flywheel cracking or warpage after installation; it can also weaken the flywheel and interfere with proper clutch release."
I wouldn’t bother about machining your Jeep’s flywheel
Judging from your pics there’s hardly any wear noticeable and if it was warped you Would’ve noticed it before you decided to replace the clutch
- Just my humble opinion,
-I just had the clutch replaced without touching The flywheel, a few weeks back on my ‘05 LJ and the flywheel was in much worse condition

detour overnout

—•|||||•—👋🏿
 
I used a dual action sander and 120 grit to dress the flywheel on my LJ before installing a new Valero clutch kit.
LUK clutch kits aren't all LUK anymore The last LUK clutch I installed had a Valeo pressure plate, which isn't a bad thing.
Valero and Sachs are probably the largest manufacturers out there.

BTW.. I have also had 4.0 flywheels resurfaced and never ran into an issue. The only issue I ever had was with a Centerforce Dual Friction clutch.
 
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