MML, BL, TT ponderings...

[derekmac]

So, let me start by telling you what I have. I have an 05 Rubi 6spd that's lifted 3" front, 2.25" rear. I have a high clearance Rough Country skid plate that I currently have lowered 2", which makes the transmission sit at the same height as it did with the factory skid plate. I have no driveline vibs as it sits now.

I want to get and install a 1" BL and 1" MML. My reason for this is to try and get the skid plate raised up some. Since the MML is usually used to cure driveline vibs, I'm thinking that installing one "should" allow me to raise the skid up. Maybe not the full 2", but some.

Is there any sort of formula for how much lift an MML takes care of? Since I have no vibs as is, how much higher would you guess that I'd be able to raise the skid? I know this will probably be a trial and error kind of thing (which is fine), but I want to get a rough idea in my head.

I should also mention that I do not have adjustable rear control arms.

 

[Chris]

All I can tell you is that you WILL need adjustable rear control arms, without a doubt.

There is no formula I know of, but I was talking with Jeff at Rokmen for a while yesterday (about 20 minutes) and asked him if I installed their transfer case skid with my OME 2.5" lift (which doesn't have vibes on the stock control arms) if I would be able to get away without adjustable control arms if I installed a 1" MML. He said he can pretty much guarantee I wouldn't be able to get away with it, and that if I tuck it, I will not only need a CV driveshaft, but I'll also need adjustable control arms, as I'll need to be able to move the pinion angle up to the same angle as the driveshaft.

Makes perfect sense if you think about it.

So by tucking it more, I think you're opening a can of worms. That's fine, but I wouldn't go into this thinking you can get away without adjustable control arms and a CV driveshaft. I think if you do, you'll be disappointed.

The only reason you're getting by with that skid plate right now as it is, is because you've got it lowered 2", which is essentially putting your transfer case right back where it would be at from the factory, hence no vibrations.

 

[JMT]

So, let me start by telling you what I have. I have an 05 Rubi 6spd that's lifted 3" front, 2.25" rear. I have a high clearance Rough Country skid plate that I currently have lowered 2", which makes the transmission sit at the same height as it did with the factory skid plate. I have no driveline vibs as it sits now.

I want to get and install a 1" BL and 1" MML. My reason for this is to try and get the skid plate raised up some. Since the MML is usually used to cure driveline vibs, I'm thinking that installing one "should" allow me to raise the skid up. Maybe not the full 2", but some.

Is there any sort of formula for how much lift an MML takes care of? Since I have no vibs as is, how much higher would you guess that I'd be able to raise the skid? I know this will probably be a trial and error kind of thing (which is fine), but I want to get a rough idea in my head.

I should also mention that I do not have adjustable rear control arms.

My setup is almost identical to yours

'05' X
6-Speed
3" front and 2.5" rear.
Stock TCase Skid (no drop)
1" MML
1.25" BL

I'm not sure how your concluding that the RC skid plate dropped 2" is keeping the transmission at the same height as the factory skid plate. If I were you I'd start removing some of the 2" drop and see how far you can go till you get vibes. That will give you your answer. At the point you get vibes add the MML and it should eliminate those vibes. Then you could try to remove some more of the drop. Unfortunately, there's no formula, just trial and error.

 

[derekmac]

I'm not sure how your concluding that the RC skid plate dropped 2" is keeping the transmission at the same height as the factory skid plate.

Before I installed the RC skid, I took measurements from my garage floor to a point on the transmission with the stock skid, and then did the same measurement after installing the RC skid. The measurement was the same.

If I were you I'd start removing some of the 2" drop and see how far you can go till you get vibes. That will give you your answer. At the point you get vibes add the MML and it should eliminate those vibes.

That's a good idea, and definitely easy enough to experiment with.

So by tucking it more, I think you're opening a can of worms. That's fine, but I wouldn't go into this thinking you can get away without adjustable control arms and a CV driveshaft. I think if you do, you'll be disappointed.

That is very possible, and most likely you and Jeff are right. But hey, I don't mind experimenting and trying different things. My whole lift was an experiment (ZJ and Crown Vic springs from a JY, stock JK shocks), and it works great.

Even if I can only gain another 0.5", I'd quite honestly be happy with that. Hell, even if I can't gain anymore that's fine by me too.

 

[JMT]

Before I installed the RC skid, I took measurements from my garage floor to a point on the transmission with the stock skid, and then did the same measurement after installing the RC skid. The measurement was the same.

Ok, so you're reasoning that since you have a Rubi, the TCase fixed yoke is not upset about the current angle, seeing that it has no vibes? I'd do the experiment I mentioned above and see how much of the drop you could lose. By the end of this, doing MML and all that, you may end up needing at least the rear upper control arms to adjust the pinion angle.

 

[Chris]

A formula would indeed be nice. One thing I've surmised though, is that it varies from vehicle to vehicle, and you should always expect the worst (and by that I mean having to spend more money, haha).

 

[derekmac]

Ok, so you're reasoning that since you have a Rubi, the TCase fixed yoke is not upset about the current angle, seeing that it has no vibes? I'd do the experiment I mentioned above and see how much of the drop you could lose. By the end of this, doing MML and all that, you may end up needing at least the rear upper control arms to adjust the pinion angle.

I'm going to guess that as it sits right now, it won't be able to be raised much or at all. I will try though, just so I know.

A formula would indeed be nice. One thing I've surmised though, is that it varies from vehicle to vehicle, and you should always expect the worst (and by that I mean having to spend more money, haha).

LOL, how true!!

 

[jjvw]

My 03 Rubi had vibes at about 3" of spring lift and a MML. We have a short rear drive shaft compared to other TJs which means we need a double cardan driveshaft and adjustable arms at lesser lift/tuck heights. It is what it is.

2003 Rubicon