Issues and Recommendations

[Omarmartinez33]

Hey there guys I’m recently rebuilding my 86 MJ. I need some Recommendations for quite a few stuff.

1st is I’m lifting my manche 4.5inches with 35 inch tires so I’m confused on the gearing issue and didn’t find anything on the forum. Is changing the gear ratio from 4.10 to 4.88 with these size tires work almost as it does now? And if not I know the Dana 30 can’t fit anything past 4.88 so what can I do or to get this done right the first time instead of putting in 4.88 ring and pinions for no reason. 

2nd I’m having a bad leak from the Pcv valve and ventilation filter valve area. I also heard people having the same problem also but I bought a new valve cover/gasket with new pcv valves and vent filter with performance spark plugs and wire set. Will I come across this problem again with these new changes? This truck doesn’t  seem to have engine or tranny problems and it shifts nice to 75mph pretty well for it’s age and mileage at 165000 on the odometer. Any other solutions to stop this bad leak? 

3rd. Other changes I’m making is timing cover and seal/gasket, oil pan gasket, pinion seal/differential servicing, changing out old hoses and clamping them right. I feel like I’m missing something and I want to get it done in an timely matter. I’ve also notice  alil leak from the tranny and gas dripping out of the fuel neck filler if I pump too fast. 

4th. I know it’s not that big of a deal but I don’t want it to get me stuck on the road one day, the fuel level reading doesn’t work but goes to 1/4 on the reading on full. I don’t know what to do for this mishap, I don’t really see videos on what could be possibly be wrong. 

5th. On the 4.5 inch lift kit it’s only offering leaf plates to put on the old leaf springs to use with it so I was wondering if this is alright if the leaf springs only have surface rust. I would also want recommendations before doing any lift work. 

I know this is a lot of questions for you guys but I love this truck already for it’s future potential(I got it 2 weeks ago) I’m upholstering the whole interior the way I like it and would also take exterior advice from you guys. I’m serious about rebuilding so let know about common mistakes 

Edited March 26, 2018 by Omarmartinez33

[Dzimm]

Your fuel level issue likely has to do with the float in the tank.  It could be bent, rusted, stuck, or broken.  Only way to tell is to take it out and inspect but be careful because the MJ fuel pump assembly is specific to the MJ and hard to find a replacement.  They pop up here sometimes.  Could also be a bad electrical connection along the way but my guess would be the float itself.  

 

As for the spring perches in the lift kit, it sounds like it is a SOA (spring over axle) conversion lift kit.  If you notice your leaf springs are currently running under the axle, or at least they were when new, this kit will require you to cut the old perches off and weld the new ones on top of the axle to mount the springs up top.  There are threads talking about this conversion that will go into more detail but the basics are that you will net about 5inches of lift from it.  There are some things to be aware of when doing this like spring wrap can become a problem.  Read up in SOA just so you are informed.  And as long as your old springs aren't sagged bad and falling apart you will have no issues reusing.  Just make sure to replace the ubolts. 

[Omarmartinez33]

Thank you sir, can the float itself be replaceable on a local auto store? If not I look through the for sale portion of the forum. Makes sense with the lift it’s just difficult finding videos on how to do it on a manche. 

[DirtyComanche]

If you're going to 35s I would recommend looking at an upgraded rear axle if you don't happen to have an AMC 20 or D44 in there from the factory.  The later XJ Chrysler 8.25, Ford Explorer 8.8, and MJ/XJ/TJ D44 are the most common options.  There is no sense spending money regearing a D35, nor changing the spring perches on it for a SOA lift.

 

Attached is a gear ratio chart to visualize how different a ratio and tire size change will be.  Yes, it will be effectively geared similar (slightly higher) to stock by going to 4.88s vs the 4.10s, and this may be fine, or you may find that the truck is a bit of a dog due to the increased rotating mass and the slightly higher gearing.

[Dzimm]

7 hours ago, Omarmartinez33 said:

Thank you sir, can the float itself be replaceable on a local auto store? If not I look through the for sale portion of the forum. Makes sense with the lift it’s just difficult finding videos on how to do it on a manche. 

No unfortunately its all one unit and no longer available.  Your best option is to diagnose and repair the unit you have.  You can test your gauge works before pulling the fuel assembly just to be sure it's not the gauge itself.  If you do need a replacement fuel pump assembly, good luck on your search.   

 

Definitely agree with DirtyComanche, upgrade the axle if it still has the Dana 35.  There are threads floating around that will help you identify the axles.  I myself did a C8.25 from a 98 XJ and it was very straight forward.  The 97+ XJ axles are stronger than the 96- ones and super easy to find.  Since the lift kit you want has the perches, the only other things you need for the axle swap are cutoff wheels and a welder.  If you do swap for an XJ axle, cut off the shock mounts and use the MJ ones and make sure to relocate the perches because they aren't in the same spots.  If you can find a factory MJ D44 or AMC 20 like Dirty mentioned, they are direct swaps (again, good luck finding those).  

[Omarmartinez33]

3 hours ago, DirtyComanche said:

If you're going to 35s I would recommend looking at an upgraded rear axle if you don't happen to have an AMC 20 or D44 in there from the factory.  The later XJ Chrysler 8.25, Ford Explorer 8.8, and MJ/XJ/TJ D44 are the most common options.  There is no sense spending money regearing a D35, nor changing the spring perches on it for a SOA lift.

 

Attached is a gear ratio chart to visualize how different a ratio and tire size change will be.  Yes, it will be effectively geared similar (slightly higher) to stock by going to 4.88s vs the 4.10s, and this may be fine, or you may find that the truck is a bit of a dog due to the increased rotating mass and the slightly higher gearing.

Do you recommend just doing the rear axle to the 8.25 and leave the front axle as is?also do I need to regear to the 4.88  as the chart indicates

[DirtyComanche]

3 minutes ago, Omarmartinez33 said:

Do you recommend just doing the rear axle to the 8.25 and leave the front axle as is?

 

I'm assuming you mean regear the front axle you have and swap a later 8.25 in the rear and regear it?

 

I'd say sure.  Personally I think 35s are at the limits of what the D30 front can handle and wouldn't do it, but with the lower output 2.5L and less throttle jockeying I doubt you could ever break the D30.  Many people run 35-37" tires on a D30 and manage to not break things very often if at all.  Also, going to a different front axle is quite expensive and involving, and only something to do if you really need to, and I don't think you're in that boat.

 

It might be worth it to pick up a junkyard newer D30 (just don't get a low pinion one) to regear, as doing gears is a complicated process and far more fun with the axle on the bench.  You could also do a full rebuild on it at that point (new ball joints, u-joints, UCA bushings, wheel bearings, newer XJ/ZJ steering parts, etc), and the newer axles take more common brake parts and have better axle shafts/u-joints and knuckles.  Then just throw it in when you do the lift, as you'll have the entire front axle unbolted at some point when installing any decent lift in that height range.

 

Another thing to consider is you might want to get a "flipsert" or have the TRE hole in the driver's knuckle welded up and tapered from the other side, it's a fairly simple mod but it does correct the steering geometry reasonably without going full bore and ordering a completely aftermarket steering system.

[Omarmartinez33]

6 minutes ago, DirtyComanche said:

 

I'm assuming you mean regear the front axle you have and swap a later 8.25 in the rear and regear it?

 

I'd say sure.  Personally I think 35s are at the limits of what the D30 front can handle and wouldn't do it, but with the lower output 2.5L and less throttle jockeying I doubt you could ever break the D30.  Many people run 35-37" tires on a D30 and manage to not break things very often if at all.  Also, going to a different front axle is quite expensive and involving, and only something to do if you really need to, and I don't think you're in that boat.

 

It might be worth it to pick up a junkyard newer D30 (just don't get a low pinion one) to regear, as doing gears is a complicated process and far more fun with the axle on the bench.  You could also do a full rebuild on it at that point (new ball joints, u-joints, UCA bushings, wheel bearings, newer XJ/ZJ steering parts, etc), and the newer axles take more common brake parts and have better axle shafts/u-joints and knuckles.  Then just throw it in when you do the lift, as you'll have the entire front axle unbolted at some point when installing any decent lift in that height range.

 

Another thing to consider is you might want to get a "flipsert" or have the TRE hole in the driver's knuckle welded up and tapered from the other side, it's a fairly simple mod but it does correct the steering geometry reasonably without going full bore and ordering a completely aftermarket steering system.

Thank you I just needed to clarify this before I do the lift itself. Regearing the rear 8.25 to 4.88 should be fine?

[DirtyComanche]

1 minute ago, Omarmartinez33 said:

Thank you I just needed to clarify this before I do the lift itself. Regearing the rear 8.25 to 4.88 should be fine?

 

Should be no issues.  The gears are commonly available, looks like Yukon, USA Standard, Dana (under their SVL line), and G2 sell them at the very least.

 

One thing to note about the 8.25 is the later ones quite often were limited slip differentials, which is an upgrade from a standard open diff but prevents the installation of a lunchbox locker later.

[Omarmartinez33]

2 hours ago, DirtyComanche said:

2 hours ago, DirtyComanche said:

 

Should be no issues.  The gears are commonly available, looks like Yukon, USA Standard, Dana (under their SVL line), and G2 sell them at the very least.

 

One thing to note about the 8.25 is the later ones quite often were limited slip differentials, which is an upgrade from a standard open diff but prevents the installation of a lunchbox locker later.

Ok I’m just going to swap both axles to the 8.25 is there anything different I got to do?

[Pete M]

wellllll, the 8.25 wasn't available as a front, so that would be a huge task in itself.    

[DirtyComanche]

I'm thinking he meant get the front D30 and the 8.25 out of the same donor....????????????

[Omarmartinez33]

2 hours ago, DirtyComanche said:

I'm thinking he meant get the front D30 and the 8.25 out of the same donor....????????????

 

2 hours ago, Pete M said:

wellllll, the 8.25 wasn't available as a front, so that would be a huge task in itself.    

Lol I feel stupid now sorry haha 

[Pete M]

the dana 30 is a decent axle and can live with 35s assuming you build it right.  that usually means expensive shafts, joints, and maybe a truss thrown in.   all depends on how crazy your offroad excursions will get.

[Omarmartinez33]

3 hours ago, Pete M said:

the dana 30 is a decent axle and can live with 35s assuming you build it right.  that usually means expensive shafts, joints, and maybe a truss thrown in.   all depends on how crazy your offroad excursions will get.

So I know I said I had the Dana 35 but I really actually have the AMC 20. So I’m good in that aspect. It’s going to be an SOA lift. Sorry for confusing y’all but I’m trying to get the hang of knowing about the truck more

[Pete M]

no apologies necessary.  we all started at the bottom rung of knowledge.    

 

can you snap a pic of the 20?  

[Omarmartinez33]

On 3/27/2018 at 4:24 PM, Pete M said:

no apologies necessary.  we all started at the bottom rung of knowledge.    

 

can you snap a pic of the 20?  

This is it sorry for the delay I was on vacation 

[Smokeyyank]

Use this for gears...

http://www.grimmjeeper.com/gears.html

 

The chart above while helpful isn't the best. It doesn't account for tcase or tranny so you can calculate your final crawl ratio.  I ran 33s and 4.11's on my XJ, according to the chart above it's in the green. Well it was wrong, since I had a AW4 should have been at 4.56. 4.11's where ok, but I would have rather ran 31's for the 4.11's. Next go around with the MJ will be 4.56 and 33's, slight overkill since it's manual, but since I'm at elevation I need some more umph getting up the hill. 

 

I have not saw it mentioned but I would also swap out your front axle for a D30 that is non CAD, especially if you're going to run 35's . If you want to do it right you're going to need a lot more than lift and gears. Steering and braking should get upgraded to if you wanna play with the big rubbers. D30's are decent axles but their geometery sucks and in single piston calipers and you start to notice the limits of a D30 on 35's. 

 

My advice, learn to wheel on smaller tires and the ins and out of your rig. Then move up to either a d44/9 combo or go tons if you wan to go 35"+.  Dollar for dollar it's silly to build a D30 to run 35's compared to a stronger axle. 

[Omarmartinez33]

1 hour ago, Smokeyyank said:

Use this for gears...

http://www.grimmjeeper.com/gears.html

 

The chart above while helpful isn't the best. It doesn't account for tcase or tranny so you can calculate your final crawl ratio.  I ran 33s and 4.11's on my XJ, according to the chart above it's in the green. Well it was wrong, since I had a AW4 should have been at 4.56. 4.11's where ok, but I would have rather ran 31's for the 4.11's. Next go around with the MJ will be 4.56 and 33's, slight overkill since it's manual, but since I'm at elevation I need some more umph getting up the hill. 

 

I have not saw it mentioned but I would also swap out your front axle for a D30 that is non CAD, especially if you're going to run 35's . If you want to do it right you're going to need a lot more than lift and gears. Steering and braking should get upgraded to if you wanna play with the big rubbers. D30's are decent axles but their geometery sucks and in single piston calipers and you start to notice the limits of a D30 on 35's. 

 

My advice, learn to wheel on smaller tires and the ins and out of your rig. Then move up to either a d44/9 combo or go tons if you wan to go 35"+.  Dollar for dollar it's silly to build a D30 to run 35's compared to a stronger axle. 

Totally agree. I was looking into the waggy 44 front axle because of someone that mention on this forum. I’m just wondering what will fit right on the rear 

[DirtyComanche]

1 hour ago, Omarmartinez33 said:

Totally agree. I was looking into the waggy 44 front axle because of someone that mention on this forum. I’m just wondering what will fit right on the rear 

 

The Waggy D44 is one of the most overrated and counterproductive swaps out there.

[Omarmartinez33]

29 minutes ago, DirtyComanche said:

 

The Waggy D44 is one of the most overrated and counterproductive swaps out there.

Why you believe that?

[DirtyComanche]

6 minutes ago, Omarmartinez33 said:

Why you believe that?

 

I'll start by saying I've done it, so I'm not looking at this from the other side of the curtain or with no practical experience.

 

The axle has some major downsides:

-Low pinion, which means reduced strength of the gearset when used in the forwards direction, but more importantly the front driveshaft is now on a much greater operating angle and is exposed to much more potential for damage.  As the engine/trans/tcase is mounted at a several degree rake in the chassis, this means the front output on the tcase is actually pointing upwards by several degrees, then add in that the pinion is now some 5" lower and you have a recipe for exceeding the operating angle on the double cardan joint at the tcase.

-Width, it's 60.5" wide or so, which seems initially to be rather ideal as that is a very close match to the stock D30 axle.  However, in order to fit tires that justify going to such an axle one inevitably needs them to be much farther outside of the wheel well than the factory put them, leading to using wheels with very low backspacing or spacers.  This will cause negative consequences in regards to the scrub radius, which does matter, do not think this is some theoretical suspension design pixie dust magic that will not impact you.  Having the scrub radius massively incorrect will result in the steering being very hard at low speed, especially with a traction aid, the steering and vehicle itself being less stable at higher speed, and the requirement for the wheels to break traction to a much greater extent than normal in order to be turned at very low speeds or while stopped.  Also, use of very low backspacing wheels does cause the same wear issues as on the D30, with wheel bearing life being reduced and the balljoints subject to greater leverage causing increased loading/wear.

-Width, again, this time in regards to the rear, the matching width rear axle will not fit well in the MJ due to the rear wheel well design/frame width, at least vs the XJ.  So again, you need the low backspacing wheels or spacers here too, especially if you just grab the matching Waggy D44/AMC 20 rear which is only 58.5" wide.

-Axle shaft strength, the outer stub shafts are NOT designed for strength, and are only 19 spline and considerably weaker than the D30 stubs.  There is solutions to this, but they both cost money, being either aftermarket 4340 outers or 30 spline outers and Yukon/Warn 30 spline drive hubs or a broached drive slug/flange.  The downside of sticking with the 19 spline outers is that none of the drive hubs available are very strong, with the OEM Spicer ones actually being the best (which I think are discontinued but some parts are being made in the aftermarket), or you could use the factory drive flanges and lose the advantage of being able to easily disconnect the front axle.  Plus, the 19 spline axleshafts, even in 4340, are not super strong, and if you do have one fail there is a reasonable change that it will destroy the spindle with it.  Going the 30 spline route is just expensive in general, but is the best option as it allows you to use the Yukon Hardcore Hubs, which are a great product in that they're very strong, low profile, and able to take abuse (no plastic dials, etc).

-Ujoint strength, because of the spindle pilot diameter and the ball joint location, the same 760X ujoint as the D30 is used on the Waggy D44, so there is no upgrade here, the only advantage is with selectable hubs you can run the high strength joints that use bushings/plain bearings without wearing them out immediately.

-Ball joint strength, recent discussion indicates that the ball joints are not really an upgrade over the D30 due to their minimal vertical separation.  The knuckles and Cs are better though.  However, you're not gaining as much here as one would hope.

-Steering angle, it's considerably less than many other axles, this was because the undersized 760X ujoint was used and limiting the angle would go a long ways to making it live, plus the negative effects of a full time 4wd arrangement are more obvious at greater steering angles (most Wagoneers are Quadratrac and come with drive flanges, the front axle is always connected).  This makes a huge difference to how maneuverable the vehicle will be in tight quarters.  You can get more angle out of them, but it's still a consideration.

 

Also to consider is that you may find the steering sucks without spending a bunch of money on it.  This is a fairly moot point as regardless of what you do you will want to spend money on steering.

 

I would never do it again.  The old F-150 D44s that are high pinion and about 64-65"~ wide, yes, I would consider one, but it is still not a cheap swap once you deal with the outer shafts/hubs.  I'd probably go with RCVs and Yukon Hardcore Hubs.  Those axles are also getting hard to find too.  I've said it before, I regret not just getting a set of JK axles for my current MJ, they have their own downsides but they're pretty decent when looking at the above list of issues, really the only big downside to me is that they don't have selectable hubs.

[DirtyComanche]

Another thing to keep in mind is that axles from different generations are not equal despite carrying the same nomenclature.

 

XJ/MJ D30 =/= JK D30

Waggy D44 (front or rear) =/= JK D44\

 

Both of the newer axles use a different gear cut, slightly different sized gears, larger/better bearings, etc, and are considerably stronger than the older generation.  Likewise some oddball axles like the Ford D50 actually has a very strong gearset, probably stronger than an old D60, despite using a fairly small 9" ring gear, as the bearings are considerably larger/better in it vs the old style D60.  The Super 60s, as they're often called, being the D60s found in the Ford Superduty trucks are also way stronger than the previous generation D60s, again with larger gears and better bearings (plus better axle shafts, ujoints, knuckles, etc).  Axles like the Ford 9" are very strong because of the gear cut/hypoid offset along with the third pinion bearing (likewise with the GM 14 bolt and Eaton HO axles).

[Pete M]

whatever you do, don't use the waggy rear axle. the mid 90s Isuzu Rodeo / honda passport have a dana 44 rear that is ~60"  and has the same 6bolt wheel pattern.  and can be found with pretty deep gears and disk brakes.  and it's a plain ol' regular 44 too, so the guts are easy to build.  

[DirtyComanche]

7 minutes ago, Pete M said:

whatever you do, don't use the waggy rear axle. the mid 90s Isuzu Rodeo / honda passport have a dana 44 rear that is ~60"  and has the same 6bolt wheel pattern.  and can be found with pretty deep gears and disk brakes.  and it's a plain ol' regular 44 too, so the guts are easy to build.  

 

Yes, that's a good bang for the buck axle.

 

The earlier Isuzu 12 Bolt is actually a good axle too, deep gears, disk brakes, stronger than a D44, but it has the same issue as the Waggy rear D44 in that it's 58.5" wide (and it doesn't have much aftermarket support).