1986 diesel Jeep Comanche TDI conversion

All Stock

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I don't have a thread yet.... my current rebuild is awaiting a new block and the hope that the machine shop that worked over the last one makes this right...

However I have a loaner mockup from Whitbread I've been using to redo all my accessory mounts. In the process I have looked closely at what it takes to put AC back in the jeep. Keep in mind you have more room than is found in a wrangler. I cant keep the alt or the pwr steering in the ahu oem location. The AC must be set on the pass side and searching has shown VW already did it.. and on the early 1.8t found in the Audi A4 and the Passat. That motor was the older style block...not the newer ALH, BRM, BHW etc... Its plug and play all the parts needed. However it does appear that you would also need the A4 compressor to work with the mount as it is different than the AHU compressor. Just marry the lines to the Jeep lines.
You can use either the jeeps brain to control the A/C pressures or use the V/W to do so.. I think its easier to use the Jeep because the VW has an adaptive idle adjustment that will handle the load at idle. Or weld in the additional bungs and have both monitor the high and low sides. I did this on my Cummins in a superduty and it worked flawless.
Keep in mind you will have to do a little research to determine the total displacement of the system when it comes to charging things. the good news is Matt is on the job and I have no doubt he will be able to get it squared away for you.

Doug
 

john.jackson9213

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Miramar, Ca. (Think Top Gun)
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1996 B4V
Finally!! Time to report some progress/issues on the build.

1) The Original Comanche drive shaft is about an inch too long now that we have replaced the AX-5 transmission with the longer AX-15. So the drive shaft will have to be shortened next week

2) Purchased some 4.0 Cherokee engine mounts to make it easier to mount the AHU engine a bit forward in the engine compartment. Easier than making them! The ALH engine mounts GasToDiesel makes are different than the AHU, so Matt has to make the custom mounts. These mounts should be delivered next week.

3) The GTC1549VZ turbo as mounted on the AHU intake is in the way of where the passenger side motor mount needs to go. So Matt is going to test fit the turbo on a B5.5 Passat maniforld. If that works, I will be looking for a B5.5 turbo manifold. If anyone knows of one for sale - please let me know.

Hopefully next week I will have some progress on these issues to report. The goal is to have the Comanche finished before the end of August and drive it back home to San Diego.
 

TDIMeister

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Try flipping the existing exhaust manifold and mounting the turbo high before sourcing a BHW one. Just need to fab a flange adapter so that the turbine outlet still points to the rear of the truck and reclock.
 
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jimbote

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spiral arm, milky way (aka central NC)
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Tacoma 4x4 converted to TDI
Try flipping the existing exhaust manifold and mounting the turbo high before sourcing a BHW one. Just need to fab a flange adapter so that the turbine outlet still points to the rear of the truck and reclock.
AHU mani is not really flippable as the turbo mounting flange is too close to head and it'll hit the intake
 

vanbcguy

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'93 Passat - AHU mTDI with GTB1756VK
I was able to get my Passat manifold from car-part.com - it's basically a website of wreckers. Paid about $100 shipped. Yes, it nicely places the turbo just out of the way of the engine mount bracket. I'm running a GTB1756VK but it should be similar in size.

Sent from my LG-H873 using Tapatalk
 

john.jackson9213

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Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
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1996 B4V
A pair of Cherokee 4.0 motor mounts were picked up on Ebay to get the TDI engine moved forward a bit. Here are some pictures of the motor mount fabrication:

You can see where the 4.0 mount is forward of the old 2.1 Renault engine mount.





New mount being tested for fit:





Both mounts as welded




Matt says the old 1.6TD manifold will require less work than the B5.5 manifold. So we found a NOS 1.6/1.9TD manifold at Cascade German/Bora Parts. Should be delivered on Tuesday.

Injectors are at DBW.LLC for rebuild and installation of Race 520 nozzles.
 

john.jackson9213

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Location
Miramar, Ca. (Think Top Gun)
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1996 B4V
Here is the 1.6/1.9TD manifold installed for a test fit:



Matt will still have some custom work to get a smooth inlet and exhaust flow, but should be fine.

Had to have a new drive shaft made. The 2 x 4 Comanche has a rubber dampner in the drive shaft, so could not be shortened. New drive shaft should be done on Thursday.

Lastly, the #3 injector I sent to DBW had a problem with a broken connector - so I shipped off a replacement to DBW on Monday. New set of rebuilt injectors and Race 520 nozzles should be delivered next Monday.
 
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xerootg

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Mk7 Golf Sportwagen, BHW Jeep XJ
Did Matt bend those mounts up himself? They look alot like the mounts that Cody Built made for the initial Wrangler they built.
 

john.jackson9213

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Mar 14, 2007
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Miramar, Ca. (Think Top Gun)
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1996 B4V
Did Matt bend those mounts up himself? They look alot like the mounts that Cody Built made for the initial Wrangler they built.

Those are stock Cherokee 4.0 mounts purchased on ebay. Nothing special. Take a look at the 3 pictures in post #38 and you will see what I got on ebay in the 1st picture. 2nd and 3rd pictures show what Matt added to the stock 4.0 motor mounts.
 
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john.jackson9213

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Location
Miramar, Ca. (Think Top Gun)
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1996 B4V
More progress and a few more issues:

Finished driver side motor mount with gusset added. But we will need a remote oil filter.




Oil pan to front axle clearance is 2.5 inches here. Matt suggest we add more, so 1.75 inch poly coil spacers were ordered that should give more clearance when they are installed.




GTC1549VZ trubo mounted on 1.6/1.9TD manifold with adapter. Notice the electronic actuator sits too high and will interfere with the hood. It will be removed since we are not using it anyway.




Here is a close up of the turbo adapter used being test fitted.

 

All Stock

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For clearance I notched my oil pan and lowered the rear of it to configure it into a rwd fashion. It also involved modifying the pickup tube. Matt knows about it as he has seen it.
The other reason I did this and I feel most guys don't consider this when going from a transverse application to a longitude driveline is that under acceleration the oil goes to the back of the pan and can potentially starve the pump. On a 4wd that has the potential to see excessive camber changes its better to have it in a deeper reservoir with the chance the pickup will remain submerged. Even more so when you consider the potential of going down a steep downhill with the motor running. Ever seen the oil in a running motor through plaxiglass...its like, where did all the oil go! You need it all to collect at the pickup and the dynamics of rwd especially in a vehicle that can see all kinds of angles.
Consider this, look at the oil pan baffling that goes into road race cars that centrifugally moves oil in the pan away from the pick up. There is a reason for this.
In my old MK3 GTI VR6 I had a sweeping on ramp I loved to hit hard regularly. With racing suspension etc and a full set of R1's on it I could push that ramp to nearly 100 mph.. lol yeah young dumb and stupid back then... but I can tell you this, by the time I got 2/3 of the way through that ramp my oil light and buzzer were flashing at me. Think about how that oil pan is similar to the stock tdi oil pan...and those cornering forces that put that oil to the side is the same difference now that you have turned the motor sideways and are moving your oil to the front or the rear of that pan. For a daily street driver.... probably not an issue.. for something that will go off road..a big problem if you find yourself on a hill for even 15 seconds and you loose oil...then motor.. then braking and power steering, etc..


BTW when you talk to Matt tell him to call me, seems given the nature of what went wrong between his machine shop and me he hasn't responded to any of my messages anymore, I know he's busy but that never stopped him before. Having said that... it wasn't Matt that was the issue. He's doing great work and the project looks awesome. He is still one of a very few I would ever consider to work on my builds.
 
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john.jackson9213

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Miramar, Ca. (Think Top Gun)
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1996 B4V
All Stock,

Should say that Matt said I would be OK to run it as is, given that I am not an off roader. Unless, maybe I really loaded down the truck. He was willing to leave it as is if that was my decision. Matt's suggestion was to use 4.0 springs for the extra lift (I have a set of NOS factory springs).

First thing I decided was to take Matt's advice on lifting the truck a little. Why? Well, I am paying Matt for his skill and for his experience, right? So figure I need to take what he says seriously.

Second, when with the poly lifts because it was exactly 1 3/4 inches. Where as adding springs was a bit non specific in how much lift I would get. And I really don't like the "idea" of a lifted Jeep for a daily driver on the road. Besides, the poly lifts were $30 including shipping. Springs would have been $55 plus shipping. (Also wanted to keep my NOS springs).

Cutting the pan was my preferred solution. But would have given me less than 3/4 inch extra clearance. Matt said the Oil Pump is very close or maybe just above the axle. I did not want to see the oil pump put in any danger. So...I opted for the 1 3/4 inch lifts, even though I don't like the "idea" of a lifted Jeep for what I do with the truck.

I appreciate your input! Hope my reply makes some sense.
 
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All Stock

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Axle is at the front of the block/ oil pan. Oil pump is in the rear. I believe I got 1-3/8" additional clearance in the front. More importantly the additional capacity and its location.

2" of lift...while a common leveling kit in the 4x4 realm actually impacts more than simply realized when it comes to suspension geometry and driveline angles. On a jeep... expect rear vibrations as you will be lifting that as well, however you may be good given the longer wheelbase and engine relocation. Keep in mind your oem shaft had a dampner in it with ideal oem angles. Rear spacer blocks will likely have the proper taper to them anyway... if its a leaf setup. Coils require arm changes. A lot of that is not so much an issue off road as the suspension goes through its full travel. On a primarily street machine its that neutral state ride height/sag going down the road that becomes the concern with a solid front axle. 2" Lifted superduties and Rams suffered from death wobble.... with just 2" spacers!! Its the small bumps at speed with angles that are technically at an extended travel already. Research caster changes.

When I got my wrangler it already had a 4" procomp lift on it. The jeep was level with an ARB front bumper. Taking out the 4.0l, putting in the TDI and using the same exact springs... the front end went up over 2" measured and this was after adding a winch to that bumper. I ended up with the 4" rear springs and using OME 2" springs in the front netting the same finish height at the 4" 4.0L procomp kit. Given you had the Renault diesel 4 cyl in there in the first place the 4.0L springs will give you that 1 3/4" + that your looking for.


All that to say...experience says there's more to consider than meets the eye.
 
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john.jackson9213

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Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
All Stock, which engine transmission adapter did you use? The gas2diesel adapter pushes the engine forward at least 2 inches. With the 4.0 engine, the oil pan sump is just behind the front axle. Above the axle, the 4.0 pan is very shallow and more than 4 or 5 inches above the front axle. Just from a quick inspection of my 91 Comanche.

Should add, this lift is only at the front. The leafs at the rear are a bastard hoge-poge that I will sort out later. Likely new stock springs and AirLift bags or air shocks.

Last comment:. It should be easy to get rid of or cut down the poly lifts if they Don't work out.
 
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All Stock

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John,
The Comanche and the Cherokee are basically the same. The Cherokee uses the exact same front suspension as the TJ aside from the high pinion 30 front axle. Things should be very similar except for the frame horns. The Cherokee is a unibody frame and the wrangler a full frame chassis. Given the Comanche is a separate bed and an earlier build I would have thought it to be full framed as well. However I can’t say I have been underneath one.

My 4.0L had the same clearances you describe. While I built my oil pan in the same manner as the oem Jeep, it wasn’t for clearance sake, it was because the oil pickup location is center to the crankshaft with a flat bottom pan. Every rear wheel drive motor in the world has the oil pickup at the rear due to the G forces that move oil. I didn’t want the motor to starve for oil. Also keep in mind the TDI is short 2 much larger cylinders thereby reducing how much it reaches forward compared to the 4.0L and that impacts the clearances dramatically.

My adapter which is not on the market was custom made to mount the motor vertical while maintaining the transmissions relationship to its mount and the tunnel intact. This keeps the manual shifter from going into the dashboard because we have to find firewall clearance. It’s even worse for the ALH and newer guys who have a vacuum pump on the end of the camshaft! So my adapter moves the motor forward 2 ¼” with the trans in the stock location. The original COTY kits didn’t move the motor that far and knowing this, mine was designed to do just that. Others have since discovered it’s an issue and have rightly adjusted accordingly.

For clearances, my harmonic balancer sits behind the axle tubes. It’s the axle housing that is the issue. I can’t use the oem TDI accessory mounts. My A/C and alt hit the steering selector shaft and the upper control arm/frame mount. My pwr steering pump was less than 3” from the axle housing with the 4.0L 4” lift springs installed and no front end on it. That got moved to engine ports side. Your truck looks to be 2wd so that should not be an issue at all for you. In addition your control arms are going to be more horizontal meaning your axle should sit even further away from the H-balancer than mine.

PM me an email addy and I’ll send you a couple shots from the original build. I’ll save them from here for if and when I do a complete build thread.
 

All Stock

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Close comparison of the pics appears to reveal that the Comanche has the motor sitting father forward then they do in a wrangler. Your shock mount is mid motor whereas mine is near my accessory belt. Unless you have a 5" plus gap behind your cylinder head and the firewall this would appear to be the case.

You mentioned a new driveshaft. If the trans is in the stock location? Using the stock trans, why did it have to be changed? If your trans was moved forward in addition to a forward mounting adapter, you may have a lot of real estate between the motor and firewall your not utilizing. I don't think that's the case though. I cant see that in the photos that you posted. It does look like that axle sits further back though.
 

john.jackson9213

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Miramar, Ca. (Think Top Gun)
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Transmission is in the same place from front to back (the transmission mount was rotated 180 degrees to get more room, left to right, for the a/c compressor. See pictures before and after from the steering column to the compressor). AX 15 transmission is longer than the AX 5, so driveshaft was shortened/replaced with new to compensate for the extra length of the AX 15.

Take a look on the driver side at where the oil fiter is. I will need a remote filter because of the driver side motor mount. Did you have to use a remote filter?
 

All Stock

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I didn't have to use a remote oil filter. I even use the largest oil cooler I could find, V6 if I recall. Reason being I use the front of the block to mount the motor. I built a truss that goes to each side to complete the three point needed to mount a drivetrain assembly. The bolt holes on the front of the block (4) were actually used as a mount location on earlier VW chassis. Its the same manner that VW mounts the ALH. Given my bay has the motor mounted further back than the Comanche I have all kinds of room to work with on that style of mount. Its already been cut up for a redesign though.
 

john.jackson9213

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Miramar, Ca. (Think Top Gun)
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More updates today. I will just cut an paste what Matt sent today.

"Working on the truck now, no way in hell stock vw power steering pump will work. Getting a volvo s40 electric power steering pump from a local wrecking yard tomorrow for $75.

It's going to by far the easiest/cheapest way to put power steering on it. For me to make new brackets to mount a pump on the passenger side is going to be far more time than $75 for a electric pump. By fooling the pump controller, it comes on 2.5 seconds after key on and runs continuously instead of varied duty as volvo intended. The motor is brushless so no worries about wearing out.
Coil spacers are in. I removed the factory 5/8" thick rubber spring pads since the poly takes the place of them, so the overall front end increase is only ~1 1/4", hardly noticeable but gets us my preferred clearance amounts. I also added a 1" spacer to where the bump stop contacts so overall travel of oem suspension is the same. When the coils were out I pushed the axle tube all the way up and the tube contacted the oil pan and 4 link bracket to ac compressor at same time bump stops touched. So the 1" spacer will let the bump stops compress and no danger of contact anywhere. But to even get that level of compression in the first place, you'd need to take a dukes of Hazzard jump.

Your rear leaf packs are in sad shape and really should be replaced. Once they are replaced and crap is out of the bed, the truck should be level."



EDIT: My plan has been to replace the springs when I get the truck home with a new stock factory type spring pack from General Spring. Just need to make up my mind if I want the Metric Ton pack (1700 lbs) or the Standard leaf pack (1280 lbs). Think it will be the Standard leaf pack and eventually some Air Lift springs to add capacity.

Edit on 8/15: Have a line on a decent used pair of Comanche springs for less than $50 - New springs are $280 to 480 per pair. Tempted to try these with the Air Lift springs.
 
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jimbote

Certified Volkswagen Nut
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Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
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Tacoma 4x4 converted to TDI
i guess your set on the volvo power steering pump huh ? there is another option using a saturn vue electric power steering unit and one of the portuguese controllers ... gonna apply this setup to my 69 mustang project ... no hydraulics, all underdash, is purely on demand, and completely automatic
 
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john.jackson9213

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Mar 14, 2007
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Miramar, Ca. (Think Top Gun)
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1996 B4V
i guess your set on the volvo power steering pump huh ? there is another option using a saturn vue electric power steering unit and one of the portuguese controllers ... gonna apply this setup to my 69 mustang project ... no hydraulics, all underdash, is purely on demand, and completely automatic
Volvo unit is mounted, so..

But that Saturn Vue unit sounds very interesting. Especially the no hydraulics part!
 

All Stock

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The Saturn brings about the issue of the actual gearbox needing the hydraulic flow. The Saturn is an electric unit in the column under the dash, at least is was on my vue.

As for the oil pan, now you can have confidence when you drive through Colorado climbing the mountains through one of those steep passes that your engine will survive it. Matt set that up perfectly.
 
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john.jackson9213

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Miramar, Ca. (Think Top Gun)
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Lots of progress to report. Lots of pictures to upload. So will take me several posts over the next couple of days.

But, here is the bottom line: I was in the mid west to see the Solar Eclipse and managed a couple days to Matt's shop. Saw the engine start for the first time while I was there and the truck moved under TDI power. By the time I left on Friday morning there were just a few items left to complete.

Here is a picture of the finished turbo mounted on the engine and connected to the stock Jeep intercooler: You will also see the VW ECU mounted under the radiator overflow reservoir.




Custom made adapter to replace VW stock plastic that pointed the wrong way.





Here is the lift pump, mounted above the remote oil filter. The Bosch relays are Jeep OEM, repurposed to power the VW ECU/glow plugs and the Volvo electric power steering pump.




This is the original Jeep solenoid relay. Turned out to be bad. Jumped it and the engine started, first time. A replacement stock Jeep solenoid was purchased and the engine would start with the key!




As you might expect, there were some wiring issues before the truck was started. One particular issue was first trying to find the stock Jeep diesel water temperature sensor from a truck bed full of parts:



Matt looked all thru the old engine parts but could not find the water temp sensor. But, when I posted a request for help on the Comanche Club forum, we got a great picture of the factory location of the sensor on the cylinder head, a picture of an old and new temp sensor PLUS the part number for a new sensor. All in only about 3 hours!!

Here is the old sensor in the Jeep/Renault head:




Here is the picture with the part number, an old sensor and a new sensor:





With that help, we found the old sensor. Matt fabricated a bung, welded it into the water lines and we had a sensor.

But we ran into another issue. The wire that came off the original sensor "Looked" green and there were several green wires on the other side of the engine bay. Turns out none of them match our original wire. So we pulled the wire back out of the cross body loom. Turned out the color was blue by the time we got to the other side of the engine bay. Oil, heat, and time had changed the wire color and fooled 4 of us who all check the wire color. That solved our water temp problem.

More problems to follow in the next post.
 
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john.jackson9213

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Miramar, Ca. (Think Top Gun)
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1996 B4V
Thursday night I left Matt at 9 p.m. We had still had no power to the interior of the cab and none of the instruments worked. Most importantly, no brake lights or running lights on the rear.

When I got back to his shop at 8:45 Friday morning, Matt looked like he did not sleep well. He worked till 2 in the morning on electrical issues. But most of the issues were solved: The power issue to the cab turned out to be old, corroded fuses in the fuse panel. Every fuse was tossed, terminals cleaned and power was restored to everything except the fan blower motor. Since the blower has power, we think the 30 year old motor is bad.

We also had the all important brake lights and running lights working properly.

Matt had also found how to hook up the "W" terminal on the alternator to grab the tach siginal. All that need to be done later was adjust the Jeep tach to the correct 900 rpm idle reading. So now the Jeep tach now match the VW ECU signal at the OBDII port.

By 10:30 a.m. it was time for me to leave the shop for a meeting in Plymouth, Michigan.

Several issues remained. The biggest was Reverse could not be engaged with the engine running. Boost was very erratic. Matt planned to change the N75 valve. There were a few smaller issues to be addressed.

By Sunday afternoon, I was back home in San Diego and the truck was still in Michigan. But I was very well pleased to see how close the truck is to being road worthy.
 
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