Sequence of correcting a crap lift

[SuperTramp]

For some reason the vibration got exponentially worse after putting the aluminum skid plate on and I’m not sure why. Prior to putting the skid plate on, it seemed to be down to a vibration at idle only which was somewhat tolerable. After the skid plate it basically rumbles/vibrates between 2 and 3k rpm and is no longer tolerable. It does it in first below 5mph so I’m fairly sure it’s not the rear driveshaft.

I spent a lot of time clearancing potential issues just in case but to no avail, the following is what I did:

-Fan hit bottom of radiator shroud, I trimmed it back so it clears
-Passenger side engine mount was very close to contacting so I filed both sides down a little, there’s a good 1/4” between now
-Exhaust contacted metal cloak oil pan skid plate, temporarily removed for now
-Exhaust contacted lower control arm mount on the frame, tightening up the bolts connecting the exhaust to the manifold cleared this (they were slightly loose and allowed the exhaust to swing
- Exhaust was hitting rear cross member of skid plate (raised up exhaust hanger mount at front cross member)
-There’s one screw coming down from the tub with a washer holding the insulation on above the muffler, it’s close but it’s not touching
-Double checked the tub above the t-case at the two high points on the drivers side, still no contact

After futzing around with it for a good 4 hours, testing driving and getting several burns, I said fuck it and took the skid plate off, but it made no difference.

I pulled the bolts for the transmission mount and got them centered and loose in the bushings (Blaine you were right, I had an extra washer on the serrated flange nut).

At this point I’m not sure what to do, but I’m glad I didn’t through the original skid plate and trans mount away.

 

[JMT]

For some reason the vibration got exponentially worse after putting the aluminum skid plate on and I’m not sure why. Prior to putting the skid plate on, it seemed to be down to a vibration at idle only which was somewhat tolerable. After the skid plate it basically rumbles/vibrates between 2 and 3k rpm and is no longer tolerable. It does it in first below 5mph so I’m fairly sure it’s not the rear driveshaft.

I spent a lot of time clearancing potential issues just in case but to no avail, the following is what I did:

-Fan hit bottom of radiator shroud, I trimmed it back so it clears
-Passenger side engine mount was very close to contacting so I filed both sides down a little, there’s a good 1/4” between now
-Exhaust contacted metal cloak oil pan skid plate, temporarily removed for now
-Exhaust contacted lower control arm mount on the frame, tightening up the bolts connecting the exhaust to the manifold cleared this (they were slightly loose and allowed the exhaust to swing
- Exhaust was hitting rear cross member of skid plate (raised up exhaust hanger mount at front cross member)
-There’s one screw coming down from the tub with a washer holding the insulation on above the muffler, it’s close but it’s not touching
-Double checked the tub above the t-case at the two high points on the drivers side, still no contact

After futzing around with it for a good 4 hours, testing driving and getting several burns, I said fuck it and took the skid plate off, but it made no difference.

I pulled the bolts for the transmission mount and got them centered and loose in the bushings (Blaine you were right, I had an extra washer on the serrated flange nut).

At this point I’m not sure what to do, but I’m glad I didn’t through the original skid plate and trans mount away.

Did you adjust your pinion angles after putting on the new skid?

 

[SuperTramp]

Did you adjust your pinion angles after putting on the new skid?

The rear yes.

 

[SuperTramp]

I also loosened the motor mount bolts and the transmission mount bolt and then re-tightened just to see if something was bound up.

 

[JMT]

The rear yes.

You need to fiddle with the pinion angles. 1* low, 2* low, 0*. Fiddle with it and find out where it’s most happy, unless you already did.

The vibes are under load which tells me they’re driveline. Everything has to be correct in the driveline. If there’s a bad u joint or centering ball or loose splines, then it can cause these problems. A problem could have shown up just with the new operating angles.

There’s a lot less rubber in the Savvy transmission mount, but usually that just increases vibes at idle. Once you get rpm’s up it smooths out. But that’s not your experience. Seems like driveline to me. Take the rear out and run it with just the front if you haven’t already.

 

[SuperTramp]

I think I’ve solved it for the most part.

Made some adjustments on both driveshafts. Took the back from 0 to about 1 degree, on the front I reduced the caster from 7 to 5.1. Didn’t seem to make any difference.

Went back to the transfer case and found it was hitting the tub just to the side of the dent I made before. I must have moved the transfer case up Andover toward the drivers side somehow. Re-clearances and now seems to be all good. There is still a vibration at idle, but that may just be what it is.

 

[SuperTramp]

Couple of pictures from today.

 

[TheBoogieman]

Couple of pictures from today.

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Fourth pic is best! @Kiwi TJ needs to step up his food game.

 

[Kiwi TJ]

Great food + Great location + Great looking TJ = Fantastic day out

 

[SuperTramp]

Great food + Great location + Great looking TJ = Fantastic day out

If you can get to the middle of nowhere, have a good view and cook a meal, I don’t know what else you could need. I was having a heated discussion over dinner regarding “clinical depression”. You don’t need drugs, you need mountains!

 

[Kiwi TJ]

If you can get to the middle of nowhere, have a good view and cook a meal, I don’t know what else you could need. I was having a heated discussion over dinner regarding “clinical depression”. You don’t need drugs, you need mountains!

You’re preaching to the choir here…. My therapy is getting out and about in my TJ finding a spot, cooking dinner off the back and just enjoy the day and the view

 

[SuperTramp]

A couple hundred miles later… I couldn’t take the vibration at idle anymore. I ended up putting the factory trans mount back in, drilled holes through the Savvy skid and with some spacers & and washers it’s working and back to “factory” vibe levels. I know I’m going to catch shit and probably create an enemy here, but I couldn’t take the vibrations anymore.

Next plan is to fab a trans skid that incorporates a mini skid for the factory trans mount studs hanging out of the Savvy skid.

 

[GoldenGorilla]

Next plan is to fab a trans skid that incorporates a mini skid for the factory trans mount studs hanging out of the Savvy skid.

That's basically how the Barnes No-lift "bolt-on" skid works. Not sure why I didn't grab a photo of it on it's own. There is a little wedge piece that the trans mount sits on. Depending on year and transmission, you set the wedge with the set of holes that line everything up. Not sure if this is along the lines of what you are thinking. The transmission mount wedge is available on it's own.

Their photos

My photo of the other side when it was just primer and you could see how the bolts for the wedge are countersunk flush from the underside on their skid.

 

[GregBelleville]

That's basically how the Barnes No-lift "bolt-on" skid works. Not sure why I didn't grab a photo of it on it's own. There is a little wedge piece that the trans mount sits on. Depending on year and transmission, you set the wedge with the set of holes that line everything up. Not sure if this is along the lines of what you are thinking. The transmission mount wedge is available on it's own.

Their photos
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My photo of the other side when it was just primer and you could see how the bolts for the wedge are countersunk flush from the underside on their skid.
View attachment 656947

Does that thing give better clearance than a stock skid?

 

[GoldenGorilla]

Does that thing give better clearance than a stock skid?

Yes. A full 1" clearance over the shovel on the later models. And a bit less to hang up on.

 

[SuperTramp]

I’m having to change out the front springs after realizing that RockJock gave me the wrong size (3” instead of 4”). I got everything apart only to find out that the replacement springs were also wrong. I did however get the bump stops in, aside from having too much caster and the driveshaft angle being wrong, does this look correct in terms of axle alignment.