Got my new lift kit (Skyjacker), installed!

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Topic author
J7M46sn
Posts: 42
Joined: Tue Nov 30, 2021 8:46 am

Got my new lift kit (Skyjacker), installed!

Post by J7M46sn »

I bought a 4" Skyjacker all spring lift kit back in November, and started the install in December. Between work, my back going out, and crappy Ohio weather with an unheated garage, I finished the install this past weekend. I do need to re-center the steering wheel yet. I just put the wheels and tires back on (32" Yokohama Geolanders that were on the truck when I bought it) and set the truck back down on the concrete floor. I have not driven the truck yet, I'm waiting for a nice warm day, and for the salt to be washed off the roads.

As this truck is a clean Arizona unit, disassembly went fairly easy, only broke one bolt, and rounded off only one brake line flare nut. The shackle bushings were somewhat of a pain, but still easier than if this truck had been an Ohio truck. My truck had the incorrect gas tank in it, so the fuel filler and vent lines were a hodge podge of hollow items screwed, glued, and stuck together. So, I bought a new MTS Company gas tank, float assembly and new hoses, while I was under the truck. I had removed my driveshafts to install the lift kit, so I went through and greased all of the U-joints, slip fittings and trunnion ball. I noticed my transfer case mount was shot, and the transmission mount was collapsing, so I replaced them. While re-installing the rear driveshaft, I noticed that the big nut retaining the transfer case yoke was loose by almost a full turn, so I tightened that. My original flexible rubber lines were really soft and dry rotted, I was glad to replace them with new extended lines. The kit raised the front of the truck 4 3/8", which will probably settle out some. The kit raised the rear of the truck only 3" though. On the original suspension, the rear of the truck sat about 1 1/2" to 1 3/4" higher than the front. The kit also levels the truck out, and this was intentional, according to Skyjacker (I called them). I'm only pointing this out to anybody who might be considering this kit.

One thing I am concerned about though, is I checked my angles at the transfer case output shaft yoke (7 degrees) and at the rear axle pinion yoke (11 degrees). I believe these angles should be the same number, which means the two shafts would be parallel to each other. The new rear springs didn't come with any sort of angled shim on the spring packs. I called Skyjacker about this yesterday, they didn't seem concerned about it at all. I feel sort of apprehensive that when I do drive the truck, it will likely have some sort of rear driveline vibration. Any opinions on this?

Anyway, cheers!
Mike
1977 Jeep J20, 360, T18, D20, D44, D60, 4:10s
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tgreese
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Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Got my new lift kit (Skyjacker), installed!

Post by tgreese »

Year/model/equipment? It matters - these vehicles were built over a 30 year span, with many changes. Put that in your signature file and it will appear with every post.

The Tom Woods site has a good article about driveshaft angles.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
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rocklaurence
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Re: Got my new lift kit (Skyjacker), installed!

Post by rocklaurence »

Yes, the angles of the Ujoints should be close to the same. Some say to have the rear set 1-2 degrees lower because the axle rotates under acceleration but that's not true. Because your only accelerating for short periods of time and at cruise everything settles. Wait for the springs to settle before making any changes and then you can order shims of Ebay.
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1978J10REDWHITE
Posts: 263
Joined: Fri Nov 20, 2020 7:25 pm

Re: Got my new lift kit (Skyjacker), installed!

Post by 1978J10REDWHITE »

I did a 3" lift on my 78 J10 last summer.
Tires are 31 x 10.50 x 15 stock rims and tires.
I measured the three angles , the output TC back plate part, the Drive line and the DIFF face angle.
Final angle was 4/2/4 an almost perfect angle geometry they setup on a drive line needs to be.
There are website that calculate things in a formulae help determine these numbers out.
I Put an inclinometer on my cell and used it, it was very accurate.
You can always buy those angle shims and create a different angle setting.
A place in Tualatin, Oregon spring shop has whatever angle you want and can ship to you or a local place if they are around near you.
I found most places anymore are useless for descent information gumby-brains are incoherent in general.

Topic author
J7M46sn
Posts: 42
Joined: Tue Nov 30, 2021 8:46 am

Re: Got my new lift kit (Skyjacker), installed!

Post by J7M46sn »

Since I had a 4 degree difference in my pinion angle and TC output shaft yoke, and the driveshaft even looked bad compared to the differential, I never even drove the truck like that. If it looks bad, it probably is... So, I installed 4 degree wedge shims at the rear axle, and now the pinion angle and TC output yoke angle are both 7 degrees, making both shafts parallel to each other. I drove the truck for the first time yesterday, and it had no weird handling, noise or vibration issues. It still rides like a 3/4 ton truck, but it does ride better with the new Skyjacker suspension and shocks, than it did with the stock suspension. It definitely looks better too! Makes me wish I would've gone 6", but I didn't want to deal with the extra problems that come with extra height. Anyway, it was worth it!
Mike
1977 Jeep J20, 360, T18, D20, D44, D60, 4:10s
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Yeller
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Location: Rogers County Oklahoma

Re: Got my new lift kit (Skyjacker), installed!

Post by Yeller »

Sounds like Patients and perseverance paid off, congrats!! 🎊
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

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