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Flat­tieThrot­tle Swap

What is your fa­vorite choice of ca­ble junk­yard gas pedal for flat­fend­ers with a Chevy V-8 swapped in?

@og_4x4 Via In­sta­gram @cap­pa­works

As you have likely al­ready found, build­ing a flat­fender is an ex­er­cise in prob­lem solv­ing for fit­ment of ev­ery com­po­nent. I have gone so far as to let­ting the steer­ing box lo­ca­tion dic­tate what the rear pin­ion an­gle will be. The whole ve­hi­cle is a puz­zle, and there is not a lot of real es­tate to work with when swap­ping in other driv­e­train com­po­nents. It would seem that a throt­tle pedal would be a sim­ple junk­yard com­po­nent to find and in­stall, but of course the flat­fender body has its ways of making that dif­fi­cult as well. Like ev­ery­thing else on a flat­fender, com­fort­able throt­tle pedal place­ment will de­pend on sev­eral fac­tors in­clud­ing trans­mis­sion se­lec­tion and lo­ca­tion, seat se­lec­tion and lo­ca­tion, and your height. Per­son­ally, I’ve never found a com­fort­able junk­yard throt­tle pedal as­sem­bly that sim­ply bolts in and works per­fect. The flat­fender footwell is cramped, so the fire­wall lo­ca­tion in ref­er­ence to the seats makes it dif­fi­cult to lo­cate a tra­di­tional throt­tle pedal. Also, the sloped flat­fender floor de­creases the amount of room you have for the throt­tle pedal to cy­cle. If you do find a us­able junk­yard pedal, you’ll more than likely need to cut it up and mod­ify it sig­nif­i­cantly for it to be com­fort­able and al­low use of full throt­tle. For all these rea­sons, I’ve al­ways found it less of a has­sle to sim­ply start from scratch and build my own throt­tle ped­als when work­ing on flat­fend­ers. You’ll need to take the avail­able space and com­fort­able foot place­ment into con­sid­er­a­tion. Sit in the Jeep with the seats and steer­ing wheel in­stalled prior to lo­cat­ing where you want the throt­tle pedal. There will be a lot of trial and er­ror, but in the end you will have a com­fort­able throt­tle pedal that func­tions prop­erly.

If you pre­fer to start with a com­plete junk­yard throt­tle pedal, you might take a look at the Jeep XJ throt­tle pedal. I have used them on other projects with some suc­cess, but it will be need to be cut, bent, and welded on to work in a flat­fender. There are also a few ad­justable af­ter­mar­ket throt­tle ped­als that could work. The Lakester and Steel Spoon throt­tle ped­als from Lokar ( look like they could be made to work in a flat­fender with­out too much dif­fi­culty.

Seal­ing 18

I am going to be re­seal­ing the oil pan on the Spicer 18 trans­fer case in my Jeep. I am hav­ing a dif­fi­cult time find­ing the bolt tight­en­ing cross pat­tern. Any ideas?

Rick Philippi

Via email

The Spicer 18 is an in­cred­i­bly ro­bust, yet crude trans­fer case. The oil pan on the bot­tom of the Spicer 18 isn’t re­ally a struc­tural com­po­nent, as ev­i­denced by the thick gas­ket it uses for seal­ing, so tight­en­ing the bolts in a par­tic­u­lar pat­tern is not all that im­por­tant. The best method to keep the Spicer 18 oil pan from leak­ing is to use a fac­tory-like thick gas­ket with gen­er­ous beads of sil­i­cone on ei­ther side and around each bolt hole. Spicer 18 oil pan gas­kets and com­plete gas­ket kits are avail­able from com­pa­nies such as Crown Au­to­mo­tive (crow­nau­to­mo­ and Omix-Ada (

Start by prep­ping the seal­ing sur­faces. Smooth the metal burs gen­tly with a file and re­move any old gas­ket materials with a scraper, wire brush, or other method. It’s not at all un­com­mon for the Spicer 18 oil pan bolt holes to be­come de­formed from over­tight­en­ing. You can flat­ten out the pan seal­ing sur­face around the bolt holes with a ham­mer and a small anvil. Let the trans­fer case drain thor­oughly and wipe out the in­side with a rag. Drip­ping oil from in­side the trans­fer case can con­tam­i­nate the seal­ing sur­faces prior to in­stalling your prepped oil pan. Clean the seal­ing sur­faces with brake cleaner or sol­vent. In­stall the trans­fer case oil pan gas­ket with beaded sil­i­cone on the oil pan and hold it in place with two of the oil pan bolts on ei­ther end. Use the two bolts and bolt holes in the trans­fer case to line up the oil pan and start the bolts by hand. Lightly in­stall the re­main­ing oil pan bolts. I usu­ally start from the cen­ter and work my way out when tight­en­ing the trans­fer case oil pan bolts, but there is no real pat­tern se­quence that needs to be fol­lowed for a good seal. You can sim­ply snug the oil pan bolts down or torque them to 15 lb-ft. For best re­sults, let the sealant cure for 24 hours prior to re­fill­ing the trans­fer case.

If your Spicer 18 oil pan is bent up or dam­aged be­yond ser­vice­able use, you can pur­chase a new one from Kaiser Willys (kaiser­ If you want some­thing a lit­tle fancier than the stock stamped-steel trans­fer case oil pan, No­vak Con­ver­sions (no­ offers a bil­let alu­minum pan. The No­vak Spicer 18 oil pan is ma­chined from 6061 alu­minum and adds rigid­ity to the en­tire Spicer 18 trans­fer case as­sem­bly. It also in­creases oil ca­pac­ity by 16 ounces to help keep the in­ter­nals well lu­bri­cated and cool.

Over Fo­cusT-Case

I have a tech ques­tion about trans­fer cases that I hope you can help me out with. I have a ’05 Wran­gler TJ Un­lim­ited with a 4.0L, NSG370 man­ual trans­mis­sion, and an NV231 trans­fer case. I am in need of ei­ther a slip-yoke elim­i­na­tor kit, or bet­ter yet, I would pre­fer to put in a trans­fer case with a 4:1 low-range gear. The ob­vi­ous first choice would be an NV241 Rock-Trac trans­fer case from a Jeep Ru­bi­con. It would bolt right up and be much cheaper than any of the af­ter­mar­ket trans­fer cases. The main prob­lem is that they are hard to come by in my area. It is much eas­ier to find an NV241 out of a JK. The JK doesn’t have the same out­put shaft speed sen­sor setup that I re­quire for my speedome­ter. I daily drive my Jeep and the speedome­ter is a must-have.

Do you know of a way to make the fac­tory TJ speedome­ter work with a JK

trans­fer case? Is it pos­si­ble to swap out the out­put shaft and bear­ing re­tainer on the JK case to a TJ style? Do you know of any com­pa­nies making a kit for this? Are there any other op­tions I am not aware of? Any sug­ges­tions to make a JK case work would be ap­pre­ci­ated. Lorne Bax­ter

Via email

As you have found, the ’07-’18 JK NV241OR Rock-Trac trans­fer case does not have a speedome­ter sen­sor and tone ring on the rear out­put. The JK gets its speed read­ing from the wheel sen­sors, which also con­trol the ABS, trac­tion con­trol, and sta­bil­ity con­trol. In or­der to use the JK NV241OR, you’ll have to add a three-wire square wave speed sen­sor and tone ring. The eas­i­est low-buck way to do this would be to fab­ri­cate and at­tach a tone ring to the rear out­put yoke, then build a bracket that at­taches to the back of the trans­fer case to hold the speed sen­sor. It’s a rel­a­tively cheap so­lu­tion. How­ever, the tone ring and sen­sor could get fouled or dam­aged by mud and other trail debris.

Re­al­is­ti­cally, I think your best so­lu­tion is to look out­side of your im­me­di­ate area for the proper TJ NV241OR Ru­bi­con trans­fer case, which will bolt up to your Jeep trans­mis­sion and give you the speedome­ter out­put that you need. A quick search on­line re­vealed sev­eral TJ Ru­bi­con NV241OR trans­fer cases on eBay ( They typ­i­cally run $2,000-$3,000 with­out a core.

Shaft­ing Ex­pe­ri­ence

I got to won­der­ing if you peo­ple at Jp ever ran an ar­ti­cle on trail re­pairs for bro­ken axles, dif­fer­en­tials, and so on. I never saw it if you did, so hu­mor me. I have a ’14 JK Ru­bi­con Un­lim­ited with 35-inch Goodyear MT/R tires, a 4-inch Mopar lift, and a lot of junk that I haul around, which in­cludes tools, re­cov­ery gear, jack, and so on. The sus­pen­sion sits about 3⁄4-inch off of the bump­stops, so I guess it’s loaded heavy.

Any­way, if I break an axle­shaft, will the tire and wheel just come off and roll down the trail? Is this Ru­bi­con Dana 44 a semi-float axle? If the axle­shaft breaks, but the wheel will stay on, is it OK to limp off of the trail, and if so should I keep it shifted in 4x4? Should I lock the dif­fer­en­tial on the bro­ken axle? For some rea­son I as­sume it will be a rear axle­shaft that breaks. Would it be bet­ter to yank the rear driveshaft and mo­tor out in front-wheel drive or vicev­ersa if it was the front axle that broke?

If I carry a spare axle­shaft, as­sum­ing the rear shafts are the same length, would the bear­ings have to be pressed on al­ready? Ex­actly how would you go about this on the trail? If this is doable, how do you get the bro­ken splined stub of the axle out of the dif­fer­en­tial? If I blow up my brand-new G2 5.13 gears, will it wreak havoc if I try to get off the trail with the other dif­fer­en­tial, and would you pull the driveshaft at this point?

I re­al­ize I went over my quota of ques­tions, but I don’t seem to un­der­stand ev­ery­thing I should know about this stuff. I’m going to Moab soon, so I fig­ure I will be bet­ter pre­pared if any­thing exciting hap­pens to my rearend. Bruce Wil­liams

Cor­rales, NM

That’s quite the myr­iad of driv­e­line trail re­pair ques­tions. Un­for­tu­nately, there isn’t al­ways a sim­ple an­swer to each ques­tion. There are many vari­ables and some­times other ob­sta­cles that will need to be over­come. For sim­plic­ity’s sake, we’ll stick with the JK axles, be­cause some other pop­u­lar axles would re­quire a slightly dif­fer­ent thought process.

If you break a rear axle­shaft, it will gen­er­ally break where the splines end. This is usu­ally the nar­row­est and weak­est area. Although, an axle­shaft could fail any­where along its length. Your JK rear axle is a semi-float­ing rear axle. The axle bear­ing is pressed onto the axle­shaft and a re­tainer plate keeps the axle­shaft and bear­ing in the axle­hous­ing. If the axle­shaft does fail at the splines, or any­where be­tween the axle­shaft bear­ing and the splines, the bear­ing re­tainer and brake caliper will keep the wheel and tire as­sem­bly on the axle­hous­ing. It will be wob­bly and un­sta­ble, but it should roll well enough to get your Jeep off of the trail and onto a tow truck. Now, if for some rea­son the rear axle­shaft fails on the out­side of the bear­ing, the wheel will typ­i­cally break free from the grasp of the brake caliper and exit the wheel­well. This type of axle­shaft fail­ure usu­ally only hap­pens in re­ally abu­sive con­di­tions.

The right and left rear axle­shafts in the ’07-’18 JK are dif­fer­ent lengths. The right shaft is 32 5⁄8 inches, and the left shaft is 311⁄4 inches. They are not in­ter­change­able, so if you want to carry spares, you’ll need both sides. Com­pa­nies such as Mopar (, Spicer (spicer­, and Yukon ( of­fer fac­tory re­place­ment axle­shafts as­sem­bled com­plete with the axle bear­ing, seal, re­tainer, and ABS tone ring.

If you are con­cerned about the strength of the stock axle­shafts un­der your loaded­down Jeep, you could re­place them with heavy-duty 35-spline parts from com­pa­nies like Dy­na­trac (dy­na­, G2 (g2axle. com), and RCV (rcvper­for­

Limp­ing a Jeep with a dam­aged axle usu­ally re­quires some assess­ment and re­pairs prior to get­ting un­der­way. You should be able to fig­ure out ex­actly what is bro­ken and know if it’s bind­ing in any way. Bind­ing can cause a lot more dam­age, so it’s best to free up what­ever is stuck in­stead of abus­ing the parts fur­ther. Lock­ing the rear locker with a bro­ken rear axle­shaft with help get your Jeep off the trail more eas­ily. Need­less to say, you will want to baby it off the trail.

A bro­ken ring-and-pin­ion could have the busted teeth jammed into other ar­eas of the axle. Ring-and-pin­ion fail­ure usu­ally re­quires that you pull the dif­fer­en­tial cover and re­move the bro­ken bits. Loose gear teeth in the axle as­sem­bly will cause it to un­ex­pect­edly and ran­domly lock up. Not even re­mov­ing the driveshaft can guar­an­tee this won’t hap­pen. If the rear ring and pin­ion are com­pletely shot, you can re­move the rear driveshaft af­ter clear­ing the bro­ken bits out of the hous­ing. In some ex­treme cases you may need to re­move the ring gear and re­in­stall the empty car­rier in the axle­hous­ing.

Re­mov­ing the splined sec­tion of a bro­ken axle­shaft from the car­rier is tricky busi­ness. Some­times you can pull it out with a pow­er­ful mag­netic tele­scop­ing re­triever tool; some­times you can tap it out with a rod from the other side; and some­times you have to re­move the car­rier from the axle­hous­ing be­fore pound­ing it out. It’s usu­ally not at all a fun job in the dirt.

Like the rear axle­shafts, bro­ken front axle­shafts re­quire sim­i­lar eval­u­a­tion prior to limp­ing out. They typ­i­cally fail at the steer­ing U-joint. If you hear pop­ping up

front, it’s im­por­tant to let off the throt­tle im­me­di­ately. A bro­ken steer­ing joint can lead to the axle­shaft ears try­ing to pass each other if you stay in the throt­tle. This can cause the ball joints to pull apart and the en­tire steer­ing knuckle and wheel to free it­self from the axle as­sem­bly. The bro­ken axle­shaft ears can also keep the steer­ing from func­tion­ing prop­erly. Front axle­shafts with a bro­ken U-joint or ears should be re­moved or re­placed be­fore limp­ing off the trail. If a splined end of a front axle­shaft breaks, it’s not as big of a deal, although you should dis­as­sem­ble the axle and re­move the bro­ken bits be­fore con­tin­u­ing on. A bro­ken front axle­shaft can flop around in­side the hous­ing, bind up, or po­ten­tially cause dam­age to the in­ner axle seal and seal mount­ing sur­face. The JK unit bear­ing does not re­quire the stub shaft to be in­stalled like some other unit bear­ings, so you can com­pletely re­move the of­fend­ing axle­shaft, stuff a rag in the axle­tube to keep the oil in, and limp off the trail in three­wheel drive. You can use the front locker in this sce­nario, but you should baby it.

Ide­ally, you can avoid all of these axle fail­ures. Driv­ing sanely and match­ing the tire size and load ca­pac­ity to your axles is the best way to avoid this kind of destruc­tion. You may want to con­sider car­ry­ing less equip­ment, es­pe­cially if you don’t need it for ev­ery trip. The 35-inch tires are about the max­i­mum tire di­am­e­ter I would rec­om­mend for the fac­tory Dana 44 axle as­sem­blies.

Laid Back

What are the rea­sons or ben­e­fits of lean­ing coilovers at an an­gle in cer­tain ap­pli­ca­tions?

@re­al­jeep­sare­full­size Via In­sta­gram @cap­pa­works

Cus­tom-fab­ri­cated sus­pen­sion con­ver­sions come in all forms. Coilover shocks have be­come a pop­u­lar, ver­sa­tile, and com­pact pack­age that pro­vides weight car­ry­ing ca­pac­ity and sus­pen­sion damp­ing. Coilovers are eas­ier to mount than most spring and shock sus­pen­sion de­signs, es­pe­cially when space is at a premium. They also of­fer near in­fi­nite ad­justa­bil­ity for spring rates and shock valv­ing.

In most cases, coilovers are mounted to the axle and in line with sus­pen­sion move­ment. How­ever, there are sit­u­a­tions where this is not al­ways pos­si­ble or de­sired. Mount­ing the coilovers at an an­gle can help fit a longer shock into a smaller area or help keep it clear of other com­po­nents that may make con­tact as the sus­pen­sion cy­cles, such as the tire, frame, and so on. Some peo­ple in­ac­cu­rately be­lieve that tilt­ing the shock at a slight an­gle will sig­nif­i­cantly al­ter the mo­tion ra­tio of the shock and the ef­fec­tive­ness of the shock valv­ing. This could not be fur­ther from the truth when deal­ing with the 1:1

move­ment of a solid 4x4 front or rear axle. The mo­tion ra­tio of a shock bolted di­rectly to a solid axle is only min­i­mally al­tered when the shock is an­gled. For ex­am­ple, on a typ­i­cal link sus­pen­sion with a coilover mounted ver­ti­cally on the axle, the coilover will com­press 1 inch for ev­ery 1 inch of sus­pen­sion travel, pro­vid­ing a 1:1 shock mo­tion ra­tio. When you an­gle the coilover to even an ex­treme and un­heard of 30 de­grees on the same sus­pen­sion sys­tem, the re­sult is a mo­tion ra­tio of 1:0.866, mean­ing the coilover shock trav­els 0.866 inches (or about 7⁄8-inch) for ev­ery 1 inch of sus­pen­sion move­ment. Tilt­ing the shock to a more rea­son­able 15 de­grees re­sults in a mo­tion ra­tio of 1:0.966. Nei­ther of these sce­nar­ios would re­quire spe­cial shock tun­ing above and be­yond a 1:1 mo­tion ra­tio ap­pli­ca­tion. By com­par­i­son, a per­for­mance A-arm sus­pen­sion might have a shock mo­tion ra­tio as high as 2:1, where the shock only trav­els 1 inch for ev­ery 2 inches of ac­tual sus­pen­sion travel. In this sit­u­a­tion, the shock valv­ing would need to be changed to com­pen­sate for the mo­tion ra­tio. Mo­tion ra­tio and other im­por­tant coilover cal­cu­la­tion data can be found on the Hyperco (hy­per­ web­site.

Hi-Low Steer­ing Swap

I am pre­par­ing to do a high-steer­ing re­vi­sion and a track bar re­lo­ca­tion to my ’01 TJ. It has a Ford Su­per Duty Dana 60 front axle. Is there any rea­son or ben­e­fit to mount­ing the steer­ing link­age to the top or bot­tom of the arm at the knuckle? Thanks for any in­sight. Bob Crooker

Via email

Gen­er­ally, the rea­son for in­stalling high­steer­ing arms on an axle is to get the steer­ing link­ages up and out of harm’s way. With this logic in mind, you’ll want them to be as high up as pos­si­ble. So you’ll usu­ally want to at­tach the link­ages to the top sides of the steer­ing arms. How­ever, when in­stalling high-steer­ing arms on any axle, it’s im­por­tant to check for clearance, es­pe­cially on Jeeps with low cen­ter of grav­ity sus­pen­sions. It’s not un­com­mon for the tie rod or drag link to bump into the frame, steer­ing box, or other chas­sis com­po­nent. You may need to cy­cle the sus­pen­sion to prop­erly check the clearance. While do­ing this, you can mock up the drag link and tie rod into both lo­ca­tions to see what fits and what doesn’t. Don’t for­get to cy­cle the steer­ing back and forth as well as cy­cle the sus­pen­sion through all dif­fer­ent sce­nar­ios. This can be achieved by safely sup­port­ing the chas­sis of the Jeep, re­mov­ing the coil springs, and ar­tic­u­lat­ing the axle with a pair of floor jacks.

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