Jounce tubes longer

Casey250

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We were pulling things apart for the new suspension and came across another variance with the diesel.

It seems that the jounce tubes are longer then gas models. I suspect to limit up travel rather then adding more bump stop shims perhaps. It seemed that the factory upper control arms might of hit cooling lines, or the top of the diff hitting the oil pan so additional bump stop was needed.

I noticed then when we trimmed 2 inches off the bottom to prepare to add Teraflex Speed bumps. After cutting 2 inches off, the Speed Bumps would not come through the top of the Jounce tube. We decided to cut an additional 1 - 7/16 inch off the tube which would give adequate room now for the Speed Bump. With the additional 2 - 1/2 inches of axle side bump stop should take care of any clearance issues with control arms and the engine/ cooling lines, as tires are going to be the limiting factor in up travel now and be bump stopped appropriately.

This may be important for others as it may affect how much additional shimming you need to do for larger tires as the jounce tube will be longer. If your adding Teraflex Speed Bumps this is something to consider. It might also be something to consider if adding a truss and how much clearance there might be around the engine oil pan and lines around the lower motor.

We aren't done yet but I figured I would post my findings. And see if others had noticed. I will cover it in an upcoming video as well. Just one more challenge of being first haha.

20200527_164533.jpg


20200527_165903.jpg
 

Motoristx

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Some things seem to be different, along with the rear track bar having the bend on the wrong side (for the gas JL exhaust). I noticed when setting up my adjustable control arms for the 3 1/2" lift, the rear axle was pushed so far back it rubbed the rear wheel well corner where the seam is, when street driving. This was using recommended upper and lower control arm measurements from older (non diesel) JL's using the same height lift. Ultimately, I ended up going shorter than the stock measurements that older JL's had, and completely collapsed the control arms as short as they could go. I'm wondering if the axle brackets are different.

17 in upper and 19 1/4 in lower is what I ended needed for the 38 Milestars.

I measured the stock one I pulled off
Upper is 17 3/8”
Lower is 19 3/4”
 
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vsav8r

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We were pulling things apart for the new suspension and came across another variance with the diesel.

It seems that the jounce tubes are longer then gas models.
This is correct. We installed Speed bumps on mine and noticed the same thing. Measured the tubes to be exactly 1.25" longer than a gas JLUR. Also, rear axle breather tube is on the other side vs gas. If you truss the rear like we did, you'll find that out along the way as well.

Gas Tube.
Jounce gas.jpg

Diesel tube.
Jounce diesel.jpg
 

vsav8r

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It might also be something to consider if adding a truss and how much clearance there might be around the engine oil pan and lines around the lower motor.
We also did an Artec on the front. No fitment or clearance issues once lifted and bump stopped correctly. What lift are you running with the speed bumps?
 

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