The Official Tummy Tuck FAQ Thread

[Ephry73]

Ive had a savvy UAM on backorder for about 3 or 4 weeks. I was curious if there is a more compact muffler that people are running with success when combined with the savvy system?

My current stock exhaust is just about rusted through so i figured now would be a good time to put something else in. Im more worried about compact size, not neccessarily sound but if i had a choice quieter is better.

I have one of those Random Technology Cats and will combining that with the Flowmaster Hushpower I'm currently running. It is a little louder than stock, but not obnoxious and gets a decent pop when decelerating which confuses the hell out of the ricer Hondas all the time. Hopefully the higher flow and pipe sizes will work well as I hope.

 

[Vasq]

@GA05LJ
I don't have a Savvy tuck specifically, but had to replace my exhaust because the muffler was not fitting. I ended up going with the thrush hush. I really like the sound, and its only 13" long (body).

 

[Vinman]

If I were adding lockers, I would want either both ends selectable or an auto front/selectable rear.

That makes perfect sense if you think about it. A locked axle wants to go in the direction the tires are pointed. When the fronts locked, it will want to go in whatever directions the tires are pointed, when the rears locked, it will always want to go straight ahead since thats the direction the rear tires are always pointed in.

 

[GA05LJ]

Good info, I will look into the thrush hush and the flowmaster hushpower.
I am basically looking a smaller package and maybe a slightly more aggressive sound but nothing too loud. My jeep is still a family vehicle on the weekends.

 

[A_Jeepin_Chaos_Seed]

Afternoon all,
So I went with the UCF extra-clearance skid which is not as flat as some of the others. I already have a MML and a BL installed. Ill be adding control arms soon and a SYE next spring. Anyone run the UCF Extra Clearance and dealt with the vibes? Not my DD and is a weekend/off road toy.

Thanks in advance.

 

[starkey480]

Afternoon all,
So I went with the UCF extra-clearance skid which is not as flat as some of the others. I already have a MML (Motor Mount Lift) and a BL installed. Ill be adding control arms soon and a SYE next spring. Anyone run the UCF Extra Clearance and dealt with the vibes? Not my DD and is a weekend/off road toy.

Thanks in advance.

I have their skid and mount and it only vibes extra with the AC turned on and even then I don’t mind them at all.

 

[Kevin Q]

I'll just add my experience with clearing the tub. I thought i had it cleared initially, then I drove it. The Jeep was loud and clunked on shifts. My final fix was basically that same at OP, but with a few lessons learned. First, I believe I had the trans bracket pulled the TC at an angle. I got the drivetrain in the right spot then got to work on the tub. I used a BFW (Big Fng Wrench). Actually I used a few angled box wrenches. I started with the nub closest to the outside. I put my floor jack under the TC. Removed all but one bolt on the transmission bracket and loosened the bracket bolts. I kept one bolt on just to help keep it in line but I did loosen it. I then used a ratchet strap to keep it from rolling into the tunnel. I then put a size 23 box wrench onto the top of the nub and jacked it up. I jacked until the rear wheel came off the ground. I did this at different angles and spots to make sure it was clear. I also used a 16 to dome it a little. Once I was confident this spot was good I went over to the boxy nub on top. I used a 15 on this one and did the same thing. After bolting it back up I drove it around for a little and she sounds like stock. Hope this can help someone doing this install.

 

[Kon]

Hi everyone,

I don't know if this is the correct thread to talk about my technical issues with my TT. If not feel free to move it to another thread.

I have installed a teraflex tummy tuck along with SYE, Rear CV driveshaft and upper rear adjustable control arms. My setup has a 2'' suspension lift and 31'' tires. I'm really happy with 31'' since they have the perfect balance for daily driving my TJ taking it off-road.

When I purchased the Teraflex TT both my local dealer and Teraflex advertised that there is no need for Body Lift. Except for the fact that personally I don't like BL, it would also give me 1'' of extra clearance that is in my case is useless and would make the 31'' tires seems small within the fenders since total lift would be about 3'' then.

My issue is that my transfer case hits the the jeep in speed bumps. I recently contacted Teraflex and they suggested to partially trim the transversal metal line that lies inside and strengthens the skid plate. However, at my garage they told me that the transfer case seems to hit the body (under the tunnel) of the jeep and that the way to solve the problem is to lower it a bit with spacers (which in the end would partially undo the whole TT project in the first place!)

Does someone has had the same issue and will trimming the skid plate make a difference if this is the case? Could it also be related to worn shocks or not correctly measured bump stops?

I would like to exhaust my options of solving this issue before going down the body lift way as explained above.

A couple of pics to help you understand better and check out the skid plate.

 

[Alex01]

Hi everyone,

I don't know if this is the correct thread to talk about my technical issues with my TT. If not feel free to move it to another thread.

I have installed a teraflex tummy tuck along with SYE, Rear CV driveshaft and upper rear adjustable control arms. My setup has a 2'' suspension lift and 31'' tires. I'm really happy with 31'' since they have the perfect balance for daily driving my TJ taking it off-road.

When I purchased the Teraflex TT both my local dealer and Teraflex advertised that there is no need for Body Lift. Except for the fact that personally I don't like BL, it would also give me 1'' of extra clearance that is in my case is useless and would make the 31'' tires seems small within the fenders since total lift would be about 3'' then.

My issue is that my transfer case hits the the jeep in speed bumps. I recently contacted Teraflex and they suggested to partially trim the transversal metal line that lies inside and strengthens the skid plate. However, at my garage they told me that the transfer case seems to hit the body (under the tunnel) of the jeep and that the way to solve the problem is to lower it a bit with spacers (which in the end would partially undo the whole TT project in the first place!)

Does someone has had the same issue and will trimming the skid plate make a difference if this is the case? Could it also be related to worn shocks or not correctly measured bump stops?

I would like to exhaust my options of solving this issue before going down the body lift way as explained above.

A couple of pics to help you understand better and check out the skid plate.

View attachment 205355View attachment 205356View attachment 205357

An easy way to clearance the transfer case would be to put something, like a large nut, on top of the transfer case where it is contacting the tub then use a jack to jack it up to "clearance" the tub and give it some extra room. Obviously, the skid would need to be removed so the TC is free to raise and lower.

Have you checked the transmission/motor mount to confirm it's in good condition and not allowing excessive movement?

 

[Kevin Q]

The transfer case should be secured and not bouncing. If it's hitting the tub see my post #247 and the OPs post.

 

[Mike_H]

Hi everyone,

I don't know if this is the correct thread to talk about my technical issues with my TT. If not feel free to move it to another thread.

I have installed a teraflex tummy tuck along with SYE, Rear CV driveshaft and upper rear adjustable control arms. My setup has a 2'' suspension lift and 31'' tires. I'm really happy with 31'' since they have the perfect balance for daily driving my TJ taking it off-road.

When I purchased the Teraflex TT both my local dealer and Teraflex advertised that there is no need for Body Lift. Except for the fact that personally I don't like BL, it would also give me 1'' of extra clearance that is in my case is useless and would make the 31'' tires seems small within the fenders since total lift would be about 3'' then.

My issue is that my transfer case hits the the jeep in speed bumps. I recently contacted Teraflex and they suggested to partially trim the transversal metal line that lies inside and strengthens the skid plate. However, at my garage they told me that the transfer case seems to hit the body (under the tunnel) of the jeep and that the way to solve the problem is to lower it a bit with spacers (which in the end would partially undo the whole TT project in the first place!)

Does someone has had the same issue and will trimming the skid plate make a difference if this is the case? Could it also be related to worn shocks or not correctly measured bump stops?

I would like to exhaust my options of solving this issue before going down the body lift way as explained above.

A couple of pics to help you understand better and check out the skid plate.

View attachment 205355View attachment 205356View attachment 205357

Can you try a lo-profile transmission mount? Where is the T-case hitting the tub?

 

[Lou]

OEM trans mounts have a lot of give to them. Ive found you need to be able to fit your hand above the transfercase to ensure it doesnt touch the tub.

 

[Kon]

An easy way to clearance the transfer case would be to put something, like a large nut, on top of the transfer case where it is contacting the tub then use a jack to jack it up to "clearance" the tub and give it some extra room. Obviously, the skid would need to be removed so the TC is free to raise and lower.

Have you checked the transmission mount to confirm it's in good condition?

Alex, you mean to put something like a washer/spacer between the TC and the body of the jeep? I haven't though of that. Is it an easy mod to suggest it to the guys at my shop?

Forgot to mention that I recently replaced the TC mount (with an aftermarket one, not mopar if that makes any difference).

 

[Lou]

You put a socket on top of the transfer case and jack the case up into the tub to clearance the tub. You need to ratchet strap the transmission to the left side frame rail. Once the tub is clearanced you put the socket back in your tool box.

 

[Alex01]

Alex, you mean to put something like a washer/spacer between the TC and the body of the jeep? I haven't though of that. Is it an easy mod to suggest it to the guys at my shop?

Forgot to mention that I recently replaced the TC mount (with an aftermarket one, not mopar if that makes any difference).

@Lou explained it perfectly. The low pro mount like Mike mentioned is also a good option but I've heard complaints about vibrations from them. I've never used one myself so I'm only repeating what I've read. Alternatively, you could also add a tiny body lift but you seem to have already ruled that idea out.

 

[bobthetj03]

Rokmen Offroad makes a baby body lift (1/2") if all you need is just a tiny bit more clearance.

 

[JMT]

Dimple the tub with a socket where it’s touching. I could do that in 45 min start to finish. So yes, easy. Or a small 0.5”BL would help.

 

[Kon]

Thanks guys for all the replies. If I get it right, essentially the suggestion is to try to bend the metal of the tub with a wrench or by lifting the TC with a washer on it to make the tub bigger and create more room for the TC and this will ensure that it won't hit the underbody of the jeep any more.

I had no idea of the 0.5'' BL which also seems a good idea since I guess you can hardly see the difference from stock. However, would I need to adjust other things as well in order to do a proper installation? Like MML or any other adjustments I don't know?

I guess I will try to do it without the BL for now and see if it works. If I find that it doesn't hit the tub in speed bumps any more, does this mean that my TC clearance is ok to off-road the jeep as well?

Finally, since nobody mentioned it I understand that bump stops have nothing to do with that issue?

Thanks again everyone!

 

[Pcleaners2]

What is a tummy tuck?
Take a look under your Jeep Wrangler TJ and one of the first thing's you'll notice is that the transfer case hangs down really low (especially if you have a Rubicon model). A tummy tuck means that you're lifting the transfer case up into the body more and getting rid of that low hanging stock skid plate in favor of something flat, that doesn't hang down (or at least doesn't hang down as low as the stock skid plate).

Why do I need a tummy tuck?
Well, you don't need a tummy tuck, but if you do a lot of offroading in your TJ then at some point or another you're going to get your transfer case skid plate stuck on something, whether it be a rock, a log, etc.. With as low as the stock skid plate hands, most serious offroaders will agree that a tummy tuck is a necessity.

What do I need for a tummy tuck?
Depending on the Jeep you have and which route you intend on going you might need one or more of these for your tummy tuck:

Body Lift- There are various routes to go with body lifts, but I always recommend a solid mount body lift such as Savvy, Rokmen, or others. Avoid the poly mount body lifts such as JKS.​

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Motor Mount Lift (MML (Motor Mount Lift)) - Is needed when doing any high clearance transfercase skid on a Jeep that has a suspension lift of 2” or more. Stockers can usually get away with out it, but if you are doing a tummy tuck chances are you aren’t keeping the stock suspension height. The reason this needs to be done is when you are stuffing your tranny and tcase farther up you want to tilt the output shaft of the tcase down to help with the geometry you are messing with. By bringing the front of the engine up, you will be able to tilt the output shaft of the tcase down. There are various MMLs out there including M.O.R.E. Bombproof mounts.​

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Double Cardan Driveshaft - Is needed when doing any tummy tuck on a Jeep that has been lifted 1.5- 2” or more via its suspension. Stockers can usually get away without it, but if you are doing a tummy tuck chances are you aren’t keeping the stock suspension height. This will be needed regardless of whether you have a Rubicon or non-Rubicon. There are a few out there (Currie, Teraflex, ect.), but the only one that I would go with is a Tom Wood.​

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Slip Yoke Eliminator (SYE) - Is needed when doing any skid on a Jeep that has been lifted 1.5" or more via its suspension. Stockers can usually get away without it, but if you are doing a tummy tuck chances are you aren’t keeping the stock suspension height. If you have a Rubicon, you will not need one of these. Many people say that the Rubicon already has an SYE, but that is incorrect. It would have to have a slip yoke in the first place to elimininate it - Rubicons have fixed flange rear outputs. There are several good kits on the market such as Advance Adapters, JB Conversions, Rubicon Express, etc..​

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Rear upper adjustable control arms - Will be needed to rotate your pinion upward. There will be some fine tuning to eliminate driveshaft vibrations. Currie, Savvy and Metalcloak are the only ones I would consider personally. I run the Savvy adjustable control arms and personally think they are one of the best options available for the TJ.​

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Rear track bar relocation bracket - This angled bracket will be needed for your trackbar when rotating the pinion. With out this bracket your stock or adjustable trackbar will bind.​

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Rear shock relocation brackets - When rotating your pinion up, you will find that the can of your shock (if you have piston down, you may not have this problem) will rub the axle. If you're looking for maximum flex, this is a good time to consider shock mount relocation to use long travel shocks. Don't overthink this one. I just went with some basic Rough Country rear shock relocation brackets and they did the job just fine! The long term solution however, would be to outboard the rear shocks in my opinion.​

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Spring perch modifications - Will sometimes have to be done, but I personally have not seen a Jeep that has absolutely needed it. Rotating the pinion will cause the spring sit a bit different- resulting in the spring trying to arc...meaning the bumpstops will no longer align. This mod is not absolutely necessary with smaller lift heights, and mainly helps suspension geometry on taller lifts.​

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Transfer case bracket - Most people run into issues with the stock transfer case shifter assembly when doing a tummy tuck. In fact, most people have problems with it even when their TJ is bone stock. The bottom line is that the factory transfer case shifter assembly is a poorly engineered piece of garbage. Things will only get worse when you do a tummy tuck. The Savvy transfer case shifter is hands down the best transfer case shifter on the market for our TJs. Savvy took the Novak design and improved on it in several areas that make it an even better choice than the Novak shifter cable. There should be no question in your mind, Savvy is the way to go. Savvy makes a transfer case shifter for the NV241 Rubicon transfer case.​

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Skids - Last but not least you'll obviously need a new skid plate if you plan on doing a tummy tuck. There's ton of options out there. Some of the more popular options include Savvy, Nth Degree, UCF, and Rokmen. I personally run the Rokmen skid on my Rubicon and love it! It's an extremely durable skid for a great price.​

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Exhaust mod - After doing the tummy tuck you'll likely find that your exhaust is sitting right against the tub of your body (which is both loud and annoying), and sometimes the tailpipe will contact the gas tank skid. Bottom line, every instance of a tummy tuck I've seen has required some light exhaust modifications. For mine, I needed to cut a few inches off the exhaust hanger where it attaches to the bracket on the transmission mount. I also had to slightly adjust the tailpipe as it was rubbing against my gas tank skid after the install. I paid about $200 for all the exhaust work, but it only took them a few hours to complete. It's pretty easy and straight forward stuff.​

Too much suspension lift for a tummy tuck?
One of the things I learned first hand when doing my own tummy tuck is that you have to be careful on the short wheelbase TJs (not the LJs). If you go over 4" of suspension lift and attempt to use an almost entirely flat skid plate (i.e. Savvy), your tucking that transfer case so far up there that it's almost the equivalent of having 7-8" of suspension lift. What I mean by that is that you have to rotate your rear pinion angle up so high inline with the driveshaft, that your rear track bar will be angled o far back that it will contact your fuel tank skid plate if you flex the suspension enough.

This can be fixed with custom fabrication, but I haven't seen any off-the-shelf kit that accounts for this. For me, at 4" of suspension lift with the Rokmen skid, my JKS rear track bar (with the track bar relocation bracket) is probably 1/4" away from contacting my fuel tank skid plate when the suspension is flexed out.

A friend of mine who has 4" of suspension lift did the Savvy skid plate, and his pinion angle was so high and so severe after the tummy tuck, that he either had to get a skid plate that hung a little lower (i.e. Rokmen), or lose some of the suspension lift to lessen the angle of the rear pinion / driveshaft.

On LJs this generally isn't an issue since you have much less severe rear driveshaft angles, and you can get away with a lot more. I'm only pointing this out because I want people to know what they're getting into. The TJ has a very short wheelbase, and therefore you really need to pay attention to driveshaft angles in the rear. There comes a point where that rear driveshaft is at such an extreme angle, that you're either going to be burning through driveshaft u-joints like crazy, experiencing a lot of vibrations that won't go away, or you're going to have your rear track bar contacting your gas tank skid.

Keep this in mind when doing a tummy tuck on your TJ!

Conclusion
Do the math on the products you need for your specific Jeep and ask yourself these questions:

• Can I afford a tummy tuck?
• Do you play in the rocks enough to justify one?

One thing is for certain, a proper tummy tuck is not cheap!

Last but not least, if there are any errors or anything that needs to be added please let me know!

I would think the way to go when running a big lift with tummy Tuck is to just simply remove the rear axle out and have new brackets welded with a correct or close pinion angle. It could be nice to have the stronger brackets as an upgrade for hard off-roading. For instance a 4” susp lift with a Ucf ultra high clearance could equal 7” of lift so the pinion angle would be around 20*. Usually a 4” lift wo tuck is 17* so I’m just working off that. That’s how east coast gear supply welds them usually and they have nice brackets with 1/4” steel.

 

[NDSpeed]

I clearanced the wrong area

there was fresh scratches in the area. Looked like the exact spot I seen in one of these posts.

had my son use a ball pen and make a decent dent. Only to be about two inches away once I reinstalled the transfer case