Colorado Daily-Driven Trail Warrior V2 - 2006 LJ

[zachpeakee]

I'm certainly no expert, but ujoints have a critical operating angle. You exceed that and they don't like it. Lowering the angle that the drivetrain is at also lowers the ujoint's operating angle. Picture your engine/trans/t-case as one unit with the motor mounts as the fulcrum point. Spicer has some good info on this.

With this being an LJ, and the rear driveshaft already sits at a fairly "neutral" position when compared to the TJ platform, I wouldn't think I'd be nearing that critical angle. Especially not on flat ground. But then again, i'm fairly new/ignorant when it comes to pinion angles and such, so I could be entirely incorrect.

 

[bobthetj03]

You'd think, right? Also keep in mind, with your 4:88's the driveshaft is spinning faster as well. Anyway, I feel your pain sir. I'll follow your other thread so as to not clutter up your build.

 

[zachpeakee]

You'd think, right? Also keep in mind, with your 4:88's the driveshaft is spinning faster as well. Anyway, I feel your pain sir. I'll follow your other thread so as to not clutter up your build.

It's definitely weighing a good bit on my mental levels!

I'm also slightly concerned, similar to what you just said, that this may be a driveshaft balance issue entirely.

I drove the LJ at 90mph when I bought it, without issue.
However because of the gearing, I could be noticing vibrations that I wouldn't have noticed before.

Although, that's nothing more than a simple SYE/Tom Woods fix. (which could ALSO be the issue entirely)...

 

[P man]

Driveshaft angle is 13.6 Degrees.

View attachment 501312




As far as I can tell, the U Joints are in good shape. I'm feeling no slop/play or binding in them.
At this point, I'm not ruling them out entirely...



This was my thought.
However, when my pinion WAS dropped to 7.9* (0.5 degrees low) the issue was the exact same.

So i'm not entirely sure, but I'm willing to drop it a full degree, just to entertain the idea of that fixing the issue.

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I made a stand-alone thread for the entire issue.
https://wranglertjforum.com/threads/figuring-out-my-driveline-vibrations-after-4-lift.76669/

I wanted to keep it all in this build thread, but feel at this point its going DEEP, and we'll soon fill up 5 pages of build-thread with pinion chit-chat.
not to mention, the additional responses could lead to some interesting theories as to what the issues might be.

Can you make the pics any darker and hard to see?

 

[zachpeakee]

Can you make the pics any darker and hard to see?

I've got all the lights on I can have brother.

I need to buy an undercarriage light for things like this.

 

[freedom_in_4low]

I'm certainly no expert, but ujoints have a critical operating angle. You exceed that and they don't like it. Lowering the angle that the drivetrain is at also lowers the ujoint's operating angle. Picture your engine/trans/t-case as one unit with the motor mounts as the fulcrum point. Spicer has some good info on this.

Driveshaft angle is 13.6 Degrees.

13.6 - 8.4 = 5.2

With your 4.88 and 33s, your driveshaft is at about 3400rpm at 65mph.

Compare that to the max rpm vs operating angle table I posted before.

This is literally the reason SYEs exist. You put a fixed yoke on that case output, driveshaft angle shallows out to 10ish thanks to the length, vs a 8.4 t case angle and your cv joint only has to handle less than 2 degrees and even then it's split across two joints.

Unfortunately I can't guarantee with complete certainty that an SYE gets rid of it either, as there are a number of us (including myself) that live with it even with an SYE. Mine onsets around 73 but it's mild enough that I can do 75 and thanks to soft top and mud tires might not know it was happening if I didn't know to feel for it (and hadn't already experienced it when it started at 65 when I had 32s and a hard top).

 

[zachpeakee]

13.6 - 8.4 = 5.2

With your 4.88 and 33s, your driveshaft is at about 3400rpm at 65mph.

Compare that to the max rpm vs operating angle table I posted before.

View attachment 501317

This is literally the reason SYEs exist. You put a fixed yoke on that case output, driveshaft angle shallows out to 10ish thanks to the length, vs a 8.4 t case angle and your cv joint only has to handle less than 2 degrees and even then it's split across two joints.

Unfortunately I can't guarantee with complete certainty that an SYE gets rid of it either, as there are a number of us (including myself) that live with it even with an SYE. Mine onsets around 73 but it's mild enough that I can do 75 and thanks to soft top and mud tires might not know it was happening if I didn't know to feel for it (and hadn't already experienced it when it started at 65 when I had 32s and a hard top).

Now that you've not only shown the chart, but explained the logic/math behind it, I'm understanding better.

As you said, and as the chart shows, I think you're closing in on what is ultimately going to be the "solution".
Because the vibes are starting almost EXACTLY where spicer claims is the optimal limit.

I'm going to wait for this ice to clear up, hopefully tomorrow, when I can safely put the LJ @ 70mph again, and see if I can't make it over to Lowes, drop the TCase with some washers, and at least get a better idea if it's joint related or not.

 

[freedom_in_4low]

Lowes

Go to Big R! They have a better fastener collection and they sell by weight so it'll cost you a fraction of what you'll pay buying it at Lowe's or Home Depot.

 

[zachpeakee]

Go to Big R! They have a better fastener collection and they sell by weight so it'll cost you a fraction of what you'll pay buying it at Lowe's or Home Depot.

I need to give more credit to Big R!
I've been inside a few times, but for some reason I always leave them as secondary option when it comes to nuts/bolts/etc.

They've got a MEAN deal on Carhartt Beanies as well. I've bought a few from there!

 

[freedom_in_4low]

I need to give more credit to Big R!
I've been inside a few times, but for some reason I always leave them as secondary option when it comes to nuts/bolts/etc.

They've got a MEAN deal on Carhartt Beanies as well. I've bought a few from there!

I miss having them around. Closest thing I have here is Tractor Supply, who doesn't have the selection, and Ace, which has the selection but costs a lot more (though still much better than the big box stores). I didn't realize but they do apparently have one location in Oklahoma... But I'm 270 miles from it, so....

 

[Mike_H]

As far as the Transfer Case, and stacking washers, etc is concerned.
I got to thinking about it, and what exactly is the purpose of doing that?

If I stack washers, essentially all that is happening is changing the output shaft angle. At which point I would need to adjust pinion angle.
ALL of which, I can do currently, without stacking washers in random places... am I missing something in my thoughts about that?

The washers were to adjust your output angles to better match the input angle at the axle, since you said you couldn't adjust your upper arms anymore. If you have regained the use of the arms to adjust angles, then the washers are only good for lowering the skid (and therfore, the T-case). Also, 0.5° low might not be enough of a change...I'd go to like 3° or 5° low then come back up in 0.5° increments and note whats going on.

 

[zachpeakee]

The washers were to adjust your output angles to better match the input angle at the axle, since you said you couldn't adjust your upper arms anymore. If you have regained the use of the arms to adjust angles, then the washers are only good for lowering the skid (and therfore, the T-case). Also, 0.5° low might not be enough of a change...I'd go to like 3° or 5° low then come back up in 0.5° increments and note whats going on.

I'm glad you said this, because I had pondered the idea of going 3* low, and working upwards.

I won't be able to try it out for a few days at speed, because there's snow on the roads now, so it'll be some time before it clears up enough to actually be able to tell!

 

[zachpeakee]

Today is a good day.

It's been 4 days since listing the TJ Sahara for sale.

I've played the facebook marketplace 'games' with a few people, and just had a buyer drive from Denver drive here to check it out.
There's a few inches of snow on the roads right now so not exactly 'ideal' for car buying purposes.
Regardless, the guy was super cool, so we went on about a 1 hour 'test drive'.
Played on the highway a bit, took it to some very mild unpaved/snowed over trails, played with the 4wd a bit, and came back home.

Needless to say, he bought the TJ.
He loved it, was excited for it, and I can say the TJ went home to a good dude!

(for anyone interested in the sale price, I listed for $9,500 and sold it to him for $9,000)

Does this make me an "LJ Purist" now?

 

[Apparition]

Today is a good day.

It's been 4 days since listing the TJ Sahara for sale.

I've played the facebook marketplace 'games' with a few people, and just had a buyer drive from Denver drive here to check it out.
There's a few inches of snow on the roads right now so not exactly 'ideal' for car buying purposes.
Regardless, the guy was super cool, so we went on about a 1 hour 'test drive'.
Played on the highway a bit, took it to some very mild unpaved/snowed over trails, played with the 4wd a bit, and came back home.

Needless to say, he bought the TJ.
He loved it, was excited for it, and I can say the TJ went home to a good dude!

(for anyone interested in the sale price, I listed for $9,500 and sold it to him for $9,000)

View attachment 501541

View attachment 501542

Does this make me an "LJ Purist" now?

The best J is LJ

 

[hosejockey61]

Congrats!

 

[zachpeakee]

With that being said, I've got a few plans for the LJ...

Currie Correctlync , Currie 4" Springs, and SYE / Tom Woods are top priority at the moment.

Planning to buy everything later tonight, so the drivetrain vibes are going to the back-seat for a few days, until the SYE / Tom Woods go in.
At which point I'll be re-doing all the pinion/drivetrain angles I've already done.

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Any opinions on SYE kits, which is best, etc?
I had considered SSYE, but from my understanding it isn't needed on the LJ, due to the longer rear shaft/lower angle.

 

[freedom_in_4low]

With that being said, I've got a few plans for the LJ...

Currie Correctlync , Currie 4" Springs, and SYE / Tom Woods are top priority at the moment.

Planning to buy everything later tonight, so the drivetrain vibes are going to the back-seat for a few days, until the SYE / Tom Woods go in.
At which point I'll be re-doing all the pinion/drivetrain angles I've already done.

-
-

Any opinions on SYE kits, which is best, etc?
I had considered SSYE, but from my understanding it isn't needed on the LJ, due to the longer rear shaft/lower angle.

Based on my luck with the JB Conversions SS SYE, I would buy their regular length SYE if I needed one.

 

[zachpeakee]

Based on my luck with the JB Conversions SS SYE, I would buy their regular length SYE if I needed one.

Teraflex/TomWoods has a promo for $635 on the Shaft/SYE combo right now.

But I've been eyeing the JB SYE as that is what I am accustomed to on the Sahara.
(although I have no real brand-affiliation as I am sure all are fairly identical)

 

[freedom_in_4low]

Teraflex/TomWoods has a promo for $635 on the Shaft/SYE combo right now.

But I've been eyeing the JB SYE as that is what I am accustomed to on the Sahara.
(although I have no real brand-affiliation as I am sure all are fairly identical)

I'm not a teraflex fan, so I would still just buy the tw shaft and the JB SYE.

I don't know of anything wrong with the teraflex SYE specifically, but I consider them in the same tier as Rough Country and metalcloak. Which might be one level higher than Steinjager, but still not great.

 

[Claytone]

A 241 or Atlas comes with the SYE already installed…….


Just saying