It's about time I got caught up on this thread. Along with it being a tough year, the Jeep went through a pretty rough patch starting with a regear and locker installation. I didn't want to mess this up, so I took the Jeep to a highly regarded local shop.
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After they put in the new gears and lockers, I had really bad driveline vibrations starting at about 45 MPH. So, we figured the slip yoke and single-cardan rear driveshaft had to go.
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While I was at it, I upgraded the transfer case shifter. Tough to see, but that's the Savvy shifter in there.
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Unfortunately, that didn't solve the problem with driveline vibrations. After checking all the angles and talking to Adams, they sent me another rear drive shaft. That helped a little, but not much.
Along the way, I broke a rear sway bar end link while flexed out on a rutted climb. That was dramatic and worth a laugh when I figured out what had happened.
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Crown came through with warranty replacements, but I decided to switch to the metal Moog links for durability.
I started messing around with the front driveshaft to see if that was contributing to the vibrations. A local shop tried to rebalance it and found that it wouldn't balance properly. So I ended up with a new front drive shaft. That helped a little, but not much.
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For kicks, I tried driving without the front drive shaft, and even without the front axle shafts. I picked up a scrap Dana 30 for cheap and tore it down for parts, so I had the outer stub shafts from that axle installed. That did a lot to reduce vibrations, but 2WD is not a permanent fix.
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The whole point of the regear was to run 33s, So I put in a Savvy body lift and got new wheels and tires.
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Everything fits nicely, with only a small amount of rubbing on the front fenders at full flex. Larger wheels slightly changed the speed at which the vibrations started, just because the drivetrain RPMs came down a little. But the vibrations were still a problem.
I'm actually really happy with the wheels and tires, though. The wheels are the cheapest ones available from Discount Tire. I think they look pretty good, although they might be a bit heavy. The tires have been very good. I went for the Kumho RoadVenture MT71s, which were just released in 2019. The tread pattern is a lot like the Patagonia's, which a lot of people here like. They handle well on the road, and the road noise is maybe a little less than my old AT tires if that's possible. They've been good on the trail so far, and I like having the sidewall lugs for the rocks around here.
I finally got around to installing the rear lights that I got for Christmas last year. They should help cut through the desert dust when we have a group of Jeeps out on the trail.
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The last step in fighting the driveline vibrations was getting the transfer case rebuilt. That helped a bit. For what it's worth, here's what I've been through while fighting driveline vibrations:
- Regear - vibrations started
- SYE and DC rear driveshaft - helped a little
- Second rear driveshaft - helped a little more
- OE Front driveshaft rebalanced - didn't work out
- Front driveshaft replaced, twice - helped a little
- New wheels and tires - no change
- Gears reworked - no change
- Transfer case rebuilt - helped a bit
The pinion angles are right where they should be. I've been through the full range of adjustments there and my local shop has double checked the setup.
After all that, I can get to 60 MPH without any noticeable vibrations and only minor vibration up to 65 MPH. Things are bad at 70 MPH, though. I wish it was better, but I can live with that. The Jeep does great on the trails, though.
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