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Your Jeep - October 2013

Posted in How To: Tech Qa on September 18, 2013
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Photographers: JP Staff

Low, Low, Low Range for a Flattie
I’m looking like crazy and can’t seem to find anyone who has regeared a Spicer 18 T-case. I want to go as low as I can with my low range in my ’46 CJ-2A. I think someone told me 3.8:1 is about it for super-low Spicer 18 gears. I was wondering if you knew anyone that may have done this or if you might have a lead on parts I can get my hands on. I’m hoping to regear my spare T-case and just swap it out for my current one.
Mike Gardner
Via facebook

I have a friend who has been running the TeraLow gears in his Dana 20 for a while. I think these are basically the same gears for a Spicer 18...if not, they appear to have a 3.15:1 kit for Spicer 18s ( are running the L-head right? If so, you could also look for a T-98 out of a CJ-5 that had the F-head. The T-98 is a predecessor to the T-18 four-speed manual and has a super-low granny First gear. T-98s for those early four-cylinders are very rare used, but do exist and with the stock bellhousing and can bolt to the back of an L-head. Herm the Overdrive Guy from ATV Manufacturing ( is now selling a T-98 conversion kit that replaces the T-90 behind early Jeep four-cylinders with a T-98. The kit has a fully rebuilt T-98 transmission, adapters, and is designed to use most of the clutch parts and linkage from your T-90. The kit also includes parts to mount the transmission to your stock crossmember. The price of the conversion is $1650 without a core charge.

spicer 18 transfer case

The Hungry YJ axle
I’ve been having an ongoing problem with my ’93 YJ. The front axle on the driver side eats axle seals all the time. I’ve replaced the seal, the axle and then the seal, and then the seal again. Now I want to know what to do next. I’ve been told that the bearings are out, the axle is bent, the housing is bent, and so on. The next trick I was told to try is to put the inner seal in and an Atlas outer seal in. Is this the best thing to do? I don’t want to get stranded, or having to crawl under to add fluid at every stop, or cause others to stop more for just me. I know where there is a CJ-5 and a CJ-7 sitting, a V-6 and V-8 model. Would either of these axles be worth a swap. Otherwise what axle would make a good swap? I live in Wisconsin where axles, motors and transmissions or transfer cases are easy to find. I’ve seen Jeeps with 30,000 miles be rusted beyond use. Any help would be great.
Jim Steppe
Via email

Jim, It sounds to me like your axle is bent, and replacement might be the easiest option for you. Unfortunately an axle from a CJ won’t work because the differential is on the other side of the Jeep (the transfer case in a CJ has a passenger-side front output on the T-case verses driver side as on your YJ). Also the bolt pattern of a CJ is different from your YJ. You’d have to swap T-cases and rework the exhaust to get the CJ parts to fit on the YJ and do something about the bolt pattern. And the only slight benefit you’d get would be locking hubs. Also the CJ-5 probably has drum brakes. Here are a few other options in increasing difficulty. If you are going for ease of replacement with no customization (welding and assembling custom parts) then you are stuck with using a stock replacement axle from a YJ. I’d look for an axle out of a ’95 YJ and make sure it has the same gearing as your current axle. Just get one from one of your local junkyards. These later YJ axles have slightly stronger axle U-joints.

If you are up to the task of a little fabrication you could build a replacement axle from a ’95-’98 Cherokee. Look for one that is a high-pinion that does not have the center axle disconnect (Most from those years should not have it). Cut the Cherokee axle brackets off and get some axle spring perches from Mountain Off Road Enterprises (PN 98102). Use these to install the non-CAD High-Pinion Dana 30 under your YJ. I basically did this in Project Ground-Up and it has worked well for about a year now.

Another alternative would be to track down a Dana 44 from an ’80-’82 Jeep Wagoneer. This axle will be a little bit stronger than a Dana 30. It also will also accept selectable locking hubs, has large rebuildable wheel bearings, large brakes (that were used on 1⁄2 ton GM trucks), and can be geared lower than a high-pinion Dana 30. You’d probably have to rebuild the axle, get new brake lines, have your driveshaft shortened, and have the axle regeared. Most of these axles have really tall (numerically low) gearing that probably won’t match your Jeep or be desirable for a lifted Jeep with larger tires. Also, this axle will have a 6-on-5 1⁄2 bolt pattern, which is different than a stock YJ (which would have a 5-on-41⁄2 bolt pattern). This means that you will need new wheels and either a set of rear bolt pattern adapters or a six-lug rear axle. Your last option to greatly increase strength, but is expensive and requires lots of customization, is to track down a Ford Dana 60 front axle. This is way overkill and should only be considered if you are gonna run big tires like 37s or larger. You could also get a new replacement axle from a company like Currie, Dynatrac, or G2 that should bolt pretty easily into your YJ. This will give you all new parts that are easy to install, but will cost more than assembling junkyard parts and then fixing them up to work for you. Hope this helps steer you in the right direction.

Overdrive Option
I have a ’79 CJ-5 with a 258 I-6, T-150 transmission and a Dana 20. I spend a lot of time driving on the interstate as well as back roads and I like to play in some mud. I was wondering what modifications and parts would I need to put an AX15 in my Jeep, or is there a better option?
Via email

I take it you are looking to bring down the RPMs on the highway? If so, the addition of a transmission with an overdrive like an AX15 or NV3550 is hypothetically possible while retaining your 258 and Dana 20. So, the parts necessary for this swap, with the use of a newer bellhousing and a transmission to transfer case adapter (from Advance Adapters or Novak Conversions, exist, but the issue for you is gonna end up being one of length and angularity of your rear driveshaft. Both the NV3550 and AX15 are about 6 or 7 inches longer than a T-150, so that means your T-case will be pushed back that far. So your rear driveshaft length and slope would be what determines if this swap is possible or impossible. The real problem is that a CJ-5 is pretty short. It’s possible that this swap could work if you could push the engine forward without the fan eating the radiator, or the rear axle backwards without the diff cover sharing space with the gas tank. Neither of those modifications will necessarily be simple, and they still may not provide the space necessary for a functional rear driveshaft with one of these five-speeds. Unfortunately, the best way to determine if this swap is possible for your Jeep involves some math and geometry. This geometric exercise depends on the slope of your transmission, the pinion angle of your rear axle, and a few different lengths. You will have to take measurements off your Jeep with the current transmission placement, and do some math, to see how long your rear driveshaft would be with the added length of the five-speed and if the angles of the rear driveshaft would allow enough travel for practical usage. To beef up for this test of geometric skill we recommend looking at the technical literature supplied to us by our friends at Tom Wood’s Custom Drive Shafts (check Once you have the measurements and angles…er, slopes, the folks at Tom Wood’s Custom Drive Shafts can help you determine if you have space for this swap. They can also build you a front and rear driveshaft that will be necessary if you can fit the five-speed tranny into your CJ.

There are a few other options for dropping highway RPMs. Look for a CJ-6 or CJ-7, both of which have more wheelbase and thus more space for transmissions and driveshafts. You could also go to taller tires (which will drop your highway RPMs), or you could go to numerically lower axle gears. These last two options will make your Jeep feel less peppy on-road, but may be much simpler than undertaking a swap like this in a short Jeep.

Extended-Range ’61 Tuxedo Park?
I just bought a ’61 Willys CJ-5. I think it’s a Tuxedo Park. It has the regular fuel tank under the driver seat. It also has a later model tank under the rear with a skidplate. Was that an option at the time? I didn’t think so, but it looks very factory.
Via email

Pete, I’d be willing to bet that someone added an extra stock gas tank under the rear of your ’61 from a later model CJ-5. That would explain why it looks factory (because it is, only for a later Jeep). Either way that’s a pretty sweet setup. Our ’56 Ground-Up has a custom mounted tank behind the rear axle, but we have contemplated adding an under seat tank for extended range. It’s a nice place to carry 10 extra gallons of fuel, nice and low, near the Jeep’s center of gravity. Our pal, Mike, added an under-seat tank to his ’75 CJ-5 that came from the factory with the tank out back, so plenty of others have added one or the other tank to their CJ-5s over the years.

willys cj 5 fuel cap

Winch Bumper Sag
I am planning on lifting my ’95 Grand Cherokee about 2 inches with a budget boost type spacer lift. I am also debating on adding a winch bumper and winch. The added weight would be about 75 pounds for the winch and 90 pounds for the bumper. Do I need to do anything special to the front springs to help support the extra weight, or will it be okay?
Bryon Connor
Via email

Adding the winch and bumper will cause the front springs to sag a little with or without the spacer pucks. It’s worth having the winch there if you ever need it. You could try to track down some 2- to 3-inch front coils and put them up front only and add the spacer puck to the rear of your Jeep. That may help level out your Jeep when you add the winch and bumper. Another option would be to try to figure out if your Jeep has the up-country package with slightly taller springs. If it doesn’t, you could try to track a pair of front up-country ZJ springs. This will mean your Jeep will be lifted by the 13⁄4-inch to 2 inches from the spacer puck plus the 1⁄2-inch from the up-country springs. All things considered, 90 pounds is not terribly heavy for a steel winch bumper, so sagging may be minimal.

TJ: Auto vs. Manual…Again
I’m looking into buying my first Wrangler, most likely a TJ. I’m wrestling with the question of auto versus stick. I’ve been on a bunch of forums and all I see is opinions. I want to know if one would perform better if I’m in water half way up my doors. Can you offer some pros and cons or direct me to a forum or YouTube channel that already goes over those kinds of questions? I’ve had enough reading that “autos are better on the road” and “I’ll never give up my stick because it’s awesome.”
Via email

Well Mathew, I can direct you to a few Jp articles that may help you wade through all the opinions on this very opinionated question. Check out “Manual vs. Auto Jeep Transmission,” (May ’11) or “Your Jeep: Manuel or Otto,” (Aug. ’12). Basically, the correct answer to this question can’t be answered without knowing more about what your future Jeep is and what you plan on doing with it. That’s because there are a few situations where a stick might out-perform an auto or vice-versa. Also, TJs came from the factory with at least five different manual transmissions and at least three different automatic transmissions. Not surprisingly, these different transmissions have different pros and cons, so the decision is gonna be different for a 4.0L ’97 TJ than for a 2.4L ’06 TJ. If all you wanted to do with your TJ was ford half-way-up-the-door deep water, either an auto or manual could be built to handle this, and both could fail as a result of this usage. But I’d say that in the short term a manual would be more robust in dealing with a little water in the system. Auto transmissions generally don’t like water, and they won’t function well with the slightest amount of water leakage. At the same time, if water gets into a manual it may keep working, but eventually if the water is not removed bearings are gonna rust and the transmission is gonna be damaged. Now, something tells me that water fording is not the only thing you are gonna be doing with your Jeep. I honestly feel that with a few exceptions, a person is best off with the type of transmission they are most comfortable with. If you like autos, get an auto; they function well off-road. If you like a manual, get one; they work well off-road, too. Otherwise, arguments can be made for both autos and manual transmissions out-performing the other in various driving scenarios. Again, this almost always boils down to nothing but stinky opinions.

A YJ in CJ Clothing
I have an ’86 CJ-7 with a bad tub, and I have been told that a YJ tub will fit. If it does, will CJ fenders, hood, and windshield frame bolt up or not?
Bill Skala
Buchanan, MI

Yes, a YJ tub will interchange with a CJ-7 tub. It is arguably a better component because all except the ’87s are plated with rust-preventing zinc from the factory, and they have the stronger door openings of later CJ-7s. Also, you have to use the CJ grille and hood together, as the YJ grille won’t match the lines of the CJ-7 hood, and the CJ-7 grille won’t fit the YJ hood. To see CJ parts bolted onto a YJ tub and modified to fit a YJ frame, check out “Turn Your YJ Into a CJ - Nose Job,” (May ’09). We would also suggest keeping the YJ windshield. While the CJ windshield will bolt up, the wipers on the YJ are way better. You’ll just need to open the holes for defrost with a Dremel or die grinder. You will also need to move body mounts because the YJ body mounts won’t match the CJ frame. Depending on if the YJ tub is auto or stick and if your CJ is an auto or stick, the floor openings and block-off plates are different and might need modifications. Also, (and this does not apply to you, but may to some CJ owners), the earlier CJ-7s have roll bars that mount to the wheel tubs, and those Jeeps will require some more hole drilling to reuse their existing early CJ-7 rollbar.

jeep yj with cj front clip

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