Project: PolarXJ (M-TDI XJ)

6_DoF

Veteran Member
Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
ok a little more general AX15 info on the rebuild. this is right up there with the easiest transmissions i've rebuilt, if you didn't have to wait on parts this would easily be a short afternoon project.

this link should be the complete rebuild manual:

Tools:
- general mechanics junk, but you will actually use that 12mm socket!
- not necessary, but a good large pair of duck-bill snap ring pliers will go a long ways
...... https://www.amazon.com/Lisle-44900-Lock-Ring-Plier/dp/B0009OR974?th=1
- basic medium harbor freight bearing splitter and press
...... most mine saw was 6ton to break loose the 1-2 hub, maybe 2ton during assembly
- 2-bolt puller

the manual shows pretty well where everything goes and orientation, but keep track on the table of what goes on where and what side first for your own sanity. pre-lub everything going back together.

the basics were remove the shift lever, a detent in the tail housing, reverse switch, bell housing, and input retainer. remove 2 keeper rings on the bearings at the front, unbolt the case n split it. a keeper plate, some more keeper rings on the main shaft, and reverse falls out. 2-bolt puller to get the 5th gear slider hub off. i left all shift rails on and just unbolted the forks, i would do this again next time for sure. takes more thought to lining things up, holding, sliding, getting the input on and the 3-4 fork at the right position, when to stab the counter shaft, but was still faster than rod assembly. once the shafts are out, pop the clips, press as needed, and throw it back together.

a little sliver hammered paint left over from like 10 years ago, also goes a looooong way during a rebuild :LOL:



 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
Very nice. A press is on my list of things to purchase.

What's your opinion on all the HD Marlin crawler upgrades?
 

6_DoF

Veteran Member
Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
I've never heard of any failures that would require any of those parts to be honest. I've had the same ax-15 in my crawler for 2 decades with zero issues. street miles, endless beating off road, even competitions ... still feels perfect. and if you are building it yourself, easy enough to add em later if you prove you need them.

i'm a big promotor of run something til you can prove you need the upgrade. just cuz someone else needs it, doesn't mean you will. one broken shaft every 5 years? stuff happens when you play games, throw another junkyard shaft in. broken shaft every other trip? upgrade.
 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
**random side note**

if i were to do this again, i would do the fuel system different. forget the factory in-tank pump and pressure regulator, forget the way too expensive 2-stage regulators to bring the pressure/flow down low enough for the TDI. I'd delete the factory pressure regulator with the adapter below, delete the factory in-tank pump, dangle a straw in the juice, and install a low pressure pump on the frame rail.

 

03Golfer

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Joined
Apr 8, 2020
Location
Canada
TDI
09 Jetta, 92 Toyota swap (ongoing), retired 03 golf
Good to hear, that is the conclusion I came to. I went with a Facet red top pump. The beauty is they allow siphon through so in case of failure, the high pressure pump can continue to suck through and get you home. A pressure gauge in the engine bay will alert of a failure if low performance is not apparent.
 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
all assembled! but back apart again ... totally forgot from back in the day, the soft top jeeps have a different t-case clocking than tin-top. 13deg down for soft, 26deg down for tin. this TJ trans had the np231 hitting the floor of the XJ 🤦‍♂️ you can see the tail housing is cast to accept both patterns, and 10deg is zero hole overlap even.

at this very moment the printer it building me a drill jig. i made it for a 12deg drop, 2 lower than the xj would have been factory. should be more than enough crossmember clearance to the yoke, will help with the front driveshaft angles, and the case should still be above the crossmember.


 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
that was seriously satisfying to use. 3D printed drill jig, alignment pins printed in that snuggly fit into the current pattern, and printed holes that i tapped for steel thread-in drill guides. factory is a 10deg difference, i made the jig 12deg up or down. so this TJ trans now has a pattern 2deg lower than factory XJ to help with front drive shaft angles, but is still well over top the crossmember. the other pattern would let a TJ owner take an XJ trans and drill it 2deg flatter than factory for more skid clearance.

I'll probably never use it again, but now i have it! ... i need to get it posted on thingiverse




 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
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1.9 ALH XJ
as i made these new engine mounts ... i started thinking ... why did i make them 1000lb-ft capable 🤦‍♂️ i guess if i was really doing that i needed to extend the gussets on the right one down between the bolts, but it'll be fine at 150hp :LOL: reused as much of the old mounts i cut up as possible, just hope the hydraulic mounts were worth the re-work.

 
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6_DoF

Veteran Member
Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
it's back on the road!! and it's soooo much better.

trans swap was a huge win, i think the ax15 gearing even feels better and works more correct with the little diesel. the rebuild is silky smooth, and the new CORE shifter is absolutely amazing. these shifter are so tight and let you feel exactly where you are.

new hydraulic engine mounts make a noticeable difference at idle for a less vibratty jeep, but i swear actually have a tiny bit more at cruise. still nicer and over-all worth it, they are the correct choice.

vnt-17 from an 04-05 Passat spools great and has to be making more air everywhere cuz the jeep is a little less smoky at part throttle. it also saw 26psi. :devilish: new downpipe is easier to get to and more air around it. even re-routed some hoses and electrical to clean up the engine bay, better access to everything now.
 
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6_DoF

Veteran Member
Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
started in on the rear this weekend and got it almost wrapped up. as i pulled the factory bumper i was super impressed with how clean this jeep is! popped off the side plastic and ... womp. probably need to get some of those rocker armor plates to cover it.

front bumper had way easier brackets, and came pre-bent. this rear came flat and the brackets alone took as long as the entire front. seriously, between the unibody mods, fitting, and final welding, they took as long. then the bumper itself, i would never buy a flat DIY bumper ever again, the amount of extra welding and finishing is just stupid.

that said, i still really like this bumper, both Mohave from DirtBound. great fit, great structure, very little fiddling outside of getting the bends right.

FINALLY got it fully welded and started in on the finishing. randomly got shown a YouTube of different levels of weld finishing last week and that was a win. i'm pretty happy with how this is coming out!

-80grit 6" flap wheel to cut down the bulk of the welds
-80 or 100grit 5" velcro sanding disc on firm foam backed pad chucked into a drill to smooth (they suggested 36grit, didn't have any)
-120grit in a random orbital sander to finish (they suggested 80grit, i had run out)






 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
SO MUCH GRINDING!! I went thru like 35 cheap-o sanding discs ... i did the back first and ground the face flat around the hitch but didn't really like it. left the front full weld around there, and now i'm debating going back to cut out the weld to re-make a full weld on the back. probably doesn't matter either way.

wife said i should clear them, the silver wouldn't look bad against the blue.


 

dieseldonato

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Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
Turned out pretty good. Bumper fab can be a pain with all the angles to get just right. I built a winch bumper for my old 93 f-150 years ago, and pretty much decided the same thing you did. No more making curved/angled bumpers from flat steel with out a press brake involved.
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
I'm still wondering why I've yet to see an xj conversion with the aw4 transmission? Its rated max 450 ft lbs of torque and stand alone controllers are now available.
 

6_DoF

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Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
I'm still wondering why I've yet to see an xj conversion with the aw4 transmission? Its rated max 450 ft lbs of torque and stand alone controllers are now available.
i don't think any jeep guy would argue that the AW4 isn't a solid trans ... but it's still an auto. needs a controller, needs cooling, and doesn't use a 3rd pedal. the kind of ppl diesel swapping a jeep are most likely stick kinda ppl i'd bet. hell, everything i own is a stick.
 

dieseldonato

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Mar 10, 2023
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Us
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2001 jetta
Meh, idk about that, defianly a preference. We four-wheeled Rausch creek for years and eventually all gave up the stick shift for an auto. Much easier to crawl with, shift, control ascents and decent. Even with 203/205 and atlas t cases we gave up running needlessly stupid low gears for no reason just trying to get a decent spread and still be able to do reasonable speed on wide open trails, without having to stop and shift the t cases out of said stupid low and into a higher gear. Non of our rigs were road legal though. Well my brothers 86 Comanche was still stick and more or less stock t case and rears, but it didn't do the hard technical trails and we had to keep it road legal since it was his dd. My friends yj and j20 both ended up 350 chevy swapped with autos and 203/205 t cases, Lincoln locked rears. My old 93 f-150 ate through aod transmissions till I stuck a good old c6 in it wirh a manual vakve body. Left what ever t-case was factory in it, and stuck 5.11 gears in it. Could still manage a bit over 25 mph in low range 3rd gear. Made a world of difference after I geared the rears in it. Only thing I wish I would have different if left the front diff open and skipped the locker. Made turning on the high traction crawling course near impossible.
 

03Golfer

Veteran Member
Joined
Apr 8, 2020
Location
Canada
TDI
09 Jetta, 92 Toyota swap (ongoing), retired 03 golf
Definitely understand the superiority of an auto in a lot of cases... but I'll still take a stick any time. I'm guessing most of these tdi swaps wind up in dual purpose rigs that don't see much hard, crawling type off road use. All generalizations, but I would agree, most tdi swappers will choose a stick. Also bear in mind, the vw community in general tends to favor stick shift more often than not.
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
Off road an automatic rocks. Granted you can't rock it like a 5 speed. The low speed maneuvering is where it's at. I'm shocked no one has made a SBC to aw4 adapter bell housing.
 

dieseldonato

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Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
Definitely understand the superiority of an auto in a lot of cases... but I'll still take a stick any time. I'm guessing most of these tdi swaps wind up in dual purpose rigs that don't see much hard, crawling type off road use. All generalizations, but I would agree, most tdi swappers will choose a stick. Also bear in mind, the vw community in general tends to favor stick shift more often than not.
Yeah, I agree for the most part, it's easier and cheaper in a swap, sometimes preferred. I've done and been involved in quite a few swaps of non native engines to other platforms and can attest an auto presents some rather unique challenges that you just don't have with a manual box.
being realistic, I have others that drive my vehicles that can't/won't drive stick for various reasons. So my once fleet of nearly all stick shift has more or less been 50-50 for many years now.
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
I am a long time lurker, but I am about to start an ALH Swap into my 2000 Cherokee with the AW4, HGM Electronics Compushift Controller is cheaper than doing a Full manual conversion for me.
Please post a build thread. Many of us would like to see reviews of a TDI rig keeping a slush box
 

6_DoF

Veteran Member
Joined
Sep 23, 2022
Location
Black n Gold Territory
TDI
1.9 ALH XJ
bumpers are DONE and on! i'm pretty happy with em. was a lot of work but learned how to finish metal better, and way better price. the front battery is just too easy for the receiver mount winch leads to reach too. needs a slightly lower back spacing wheel and 31s, but that's a next year issue. also need to make some rocker armor to cover where the old bumper used to.

Spartan locker in the back is 1000x better driving in the rain, i actually have the traction to accelerate now. found the worst over-use of RTV i've ever seen when i popped the diff :lol:





 

6_DoF

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Joined
Sep 23, 2022
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Black n Gold Territory
TDI
1.9 ALH XJ
i used to compete crawling in the RC Rocks comps at Rausch, i love that place! since moving to the other side of the state, the fuel and turnpike fees make it harder to get over there. i really haven't gotten out with the rig much this year.

the YJ is still a stick and i'd have it no other way! i even tow it to the trail with a stick.



 
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Mozambiquer

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Mar 21, 2015
Location
Versailles Missouri
TDI
2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
bumpers are DONE and on! i'm pretty happy with em. was a lot of work but learned how to finish metal better, and way better price. the front battery is just too easy for the receiver mount winch leads to reach too. needs a slightly lower back spacing wheel and 31s, but that's a next year issue. also need to make some rocker armor to cover where the old bumper used to.

Spartan locker in the back is 1000x better driving in the rain, i actually have the traction to accelerate now. found the worst over-use of RTV i've ever seen when i popped the diff :lol:





I've been following this project and it makes me want to do one of these swaps... I'm maybe getting a pair of XJs in the next few days or so. They both run and have the 4.0, ill probably leave them like that for now, but maybe do a swap someday, depending on how nice they actually are and if I'm successful in filing for titles for both...
 
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