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Letter 44

Isuzu Trek Members Infoletter #44
April 2021

Welcome to Isuzu Trek Infoletter #44.

The I-Trek infoletter mailing list is now managed in a Google Group: (!forum/i-trekinfoletter).  If you would like to be included in this exclusively Isuzu Trek group please request inclusion or e-mail the editor Bret Medbury for info at isuzutrek (at) or islandduo (at)

Awesome Honey Hole of Info – NWTFC & Mary Carlson
Does the rear bumper really fasten the rear cap??  – John
Loose or Galloping Dash Repair  – John
Proper wheel nut torque  – Bret
The Eddie Story, actually more on tires and nut torque – Mike
Luci Lights – Bruce
JR403E Transmission trouble and replace – Robert
Additional Note On Tranny Rebuild – Bruce
Additional Undercarriage Storage – Greg
MacGyver method of valve adjusting – Pat
HWH Leveler System Pump Source – Denney
Overheating Trek – Ken
Raising Your Right Mirror – Greg
High Tech Anti Siphon for Fresh Water Tank  – Greg 
See Level II Tank Gauge Upgrade – Bret

I repeat the below as the info is so precious:

Awesome Honey Hole of Info    Thanks to Mary Carlson and the Northwest Trek Fun Club 

Did you know there is a cache of Isuzu specific information which the Northwest Trek Fun Club has graciously provided us space to store on their website at   Also you will find all the history and previous issues of this Infoletter and other information there as well, just use the drop down under the Infoletter tab.  Also if you have or know of information that you feel would be an asset to this collection of information please inform myself at islandduo(at) or Mary Carlson at hmcarlson30(at) 

Does the rear bumper really fasten the rear cap??    Thanks to John Smith @  jsmith(at)

Decided to take self-isolation a step further and took off on a lone road trip up 395/95 and up to Boise.

I had removed rear bumper to have it repaired just prior to trip, but did not think much about it, encountered heavy winds in Great Salt Flats area yesterday evening and heard something banging around in back. Found the exhaust vent broken and flapping which I THOUGHT explained it.

It seems the rear bumper actually helps the whole backend stay attached to the TREK!!!

I wondered what all that caulking was about, now I know!

Parked next to ACE Hardware in Lone Pine to make temp repair – See photos.


Loose Or Galloping Dash Repair  Thanks to John Smith @ jsmith(at)

Galloping Dash Fix ‘93 2830

The Dashboard on Isuzu Chassis Treks was designed to fit the cab of ISUZU NPR Truck and is narrower that the TREK body.

A set of spacers with flanges was bolted onto each side of the dash and in turn bolted to the walls of the coach. Unfortunately, nobody told the guy making the frame to allow for it so the dash has a dozen beefy sheet metal screws driven into…. well not much of anything really, other than the plywood inner skin of the coach.

Over 70,000 miles these screws loosened up and fell out allowing the dash to virtually be freestanding resulting in the whole dash shaking and vibrating madly anytime road irregularities are encountered. I will do my best to describe how I secured mine, I’m not saying it’s perfect or it will last forever but it did tame the beast significantly.

The original holes showed me the dash was not in the exact same position as when it was first installed but I considered the discrepancy not sufficient to need remedying.

Measuring back from the inside of flange and using the corner of the wall as reference point I measured 5 3/4”. The fiberglass Cap is about 1/8” thick and wraps over the corner so that gave me 5 7/8”.  Moving around to the outside I measured back 5 3/8” (original measurement was from inside corner of flange remember, we need to allow space for the bolt to land in center of flange).  

Install a strip of masking tape and draw in your vertical reference line, decide on number of bolts and mark their positions horizontally then drill a 1/8” test hole (easy to caulk if wrong), check that your pilot hole is sufficiently centered on the flange to allow for washer to land properly, adjust if necessary then Drill all bolt locations with 1/8” bit. (Flange wants to bend out of the way but a sharp bit got through ok for me without someone having to back it up).

I selected 1/4” x 20 x 2 1/2” Coach bolts, nothing fancy, straight off Home Depot shelf, plain washers and Nylocks. You could go 5/16” or even 3/8”, time will tell if that is sufficient, for now it works.

Drilling out through holes to 9/32” gave me sufficient clearance for the bolts. Reaming out the Aluminum skin only to 5/16” allowed the corners of the square part of the coach bolt to be tapped gently into place with a hammer and provided enough of a “key” to resist the bolt spinning.

I installed 3 bolts vertically and just one on the Horizontal section (see photo), judging by what others have installed this should prove sufficient, if not, more can be added later. I installed all bolts loosely then pried the flanges away and got some panel adhesive in the joint before tightening everything snug.

Editor’s Note: Literally all ‘91-‘93 Treks suffered this problem along with a lesser number of 94s. The flange continuing down and aft also needs to be sealed using construction adhesive, but then can be pulled up tight with self-taping screws after the upper portion has been pulled together with the bolts. I repaired our ‘93 Trek in a similar manner 100,000 miles ago using two 5/16” bolts each side and it has held fine.

Making this repair also offers the added bonus of what feels like a smoother ride up front. Eliminating the jumping dash generates the illusion of a significantly improved ride just by making everything much more solid.



















Proper Wheel Nut Torque  Thanks to Bret Medbury  islandduo(at)

I want to caution everyone that tire places chronically over-tighten (over-torque) the wheels on an Isuzu Trek apparently because the nut is larger than the nut on an 18 wheeler. Anyway the proper torque is 325 Lb/Ft and you must insist that it be done by hand.

Sometimes they get the wheels so tight with their big air wrenches they cannot be removed by the roadside service guy. If they even try to run the nuts down with their big (truck) air wrench they will already be too tight and putting the hand torque wrench on it then is useless. I insist they run the nuts down with the same air wrench they use on a car then torque to 325 with the hand torque wrench.

OBTW the left side nuts and studs are left hand threaded. Some Isuzu Trekkers have found theirs torqued to over 1,000 lb/ft.

The Eddie Story, actually more on tires and nut torque  Thanks To Mike McNaull mikemcnaull(at)

Hi Trekers if that is the correct term to use.

We have a 1993 Safari Trek with 106,000 miles that we bought in 2014 in Alabama for $9000.  We are the 3rd owners.  Our Trek, which we named Eddie after the Chevy Chase Christmas movie, had some roof leak issues where the luggage rack was attached which stained the ceiling.  I repaired the leak, sealed all the roof joints and removed all the ceiling stains.  We also replaced the toilet with a porcelain one. 

Since we got Eddie we have only taken him on two trips, once to Jackson, MS where our daughter lives, then continued to Grand Isle, LA.  We also took Eddie to the PGA Greenbrier Golf Tournament that is near us.  Eddie is fun and cool. 

Well, Eddie has sat in our barn in WV for the last 5 years since my wife’s mom moved in with us.  We have gone back and forth as whether to sell or keep Eddie.  I have started and warmed up Eddie every few weeks.  Last year I replaced the batteries, got a new inspection sticker for the first time in 4 years and drove 40 or so miles.  We moved Eddie to our other house on the farm where I had a 30-amp service.  I tested all the systems and to my amazement, everything worked as advertised.  We also painted the inside to freshen it up.  Unfortunately due to 94 year old mother living with us, we didn’t get to use Eddie last year.  

So this fall, we did the same drill to check out all the systems and was able to make arrangements for mom.  In December, we left the farm and headed to the Outer Banks in NC.  During the trip, I knew ahead of time that the tires were the weak link but thinking it was cool/cold the tires would hold.  Sure enough we had a back rear inner tire blow out as we made a turn at a stop light so it was a very controlled maneuver except for the noise as the tire took out our exhaust pipe over the drive shaft.  I looked out the rear camera and saw parts going down the road behind us.  Luckily we were able to pull into a lumber mill where a very friendly man got a battery power grinder tool to remove the pipe and also called a local tire shop.  We ended up replacing all 6 tires.  Last year I actually ordered new tires but my local garage couldn’t loosen the lug nuts so back in the barn it went. 

Well, the week long journey was a great success and everything worked fine until the shower faucet started to leak.  Luckily we were able to get the exact replacement part the next day.  During our 1000 mile journey we averaged about 13 mpg going from our steep mountains to the ocean and back.  I love Eddie.

Thanks to Islandduo for keeping this site full of info. 

Luci Lights  thanks to Bruce Matlack   matlackwindsurfing(at) 

I have been using three Luci solar lights while living aboard to save my batteries.  My one, coach, 110 light in the ceiling was a goner on delivery 13 years ago.  I hook the Luci lamps to convenient places in the coach with aluminum carabiner clips and. Move them around as necessary.  I use them on my boat as well – check ‘em out online.  I use a head lamp a lot as well. MPOWERD Luci Pro Outdoor 2.0: Solar Inflatable Lantern + Phone Charger with 150 Lumens, Lasts up to 50 Hours, All-in-One Lantern with Built-In USB Port, Waterproof, Compact, Lightweight: Sports & Outdoors

JR403E Transmission Trouble and Replacement   Thanks to Robert  elvis45687(at)

Jatco JR403-E Availability

The prior owner of my 1994 Trek had used a “fix a leak” from a bottle type product to repair what was a trans leak. A few months into my ownership, it had become worse so in 2015 I took it in for repair to the local Izusu/GMC shop. Upon diagnosis, they suggested a partial rebuild. I asked about a replacement option, but the service manager at that time told me he had considered that as well but was unable to source a Jatco from a reputable parts dealer and it would cost me more. With that info in hand, I went with the rebuild. The trans worked fine, although shifting did not seem quite as smooth as before. 

Unfortunately, about 4-5,000 miles later the trans started acting up again in January 2021 by sticking in first and finally no engagement of gears. Initially, I did all of the known remedies to reset the TCM but nothing worked. I headed back to the same shop and was told it could be many things like line pressure, a solenoid, but they would drop the pan for inspection only if needed. A few days later I get a call from the mechanic that a substantial amount of metal shavings were in the pan. Speak with what is now a different service manager than before to discuss options. This time a reman Jatco had been found out of state and repair was completed three weeks later. The new trans was $3,800 and $1000 for installation. Upon driving the Trek home from the shop it was like driving a brand-new RV. Far more pick up and believe it or not, better on the climbs. 

Additional Note on Tranny  Thanks To Bruce Matlack    matlackwindsurfing(at)

My tranny rebuild was done under budget and is perfect – about $4800 by Lee Country transmission and exhaust in Ft. Myers.  They put two coolers on back-to-back as they said by the looks of the tranny debris, too much heat was evident.  My rig may have been towing a TOAD the first 13000 mi of its life.  So I don’t know what that load may have caused.  They just do trannys and exhaust systems.

Additional Undercarriage Storage  Thanks to Greg   grrreaat(at) 

Here are some pics of that storage deck I mentioned. I welded it custom to fit in the space between our black tank and the aft storage box, about a foot wide and 4 foot long. It’s welded out of 1/8 inch (?) mild steel for lightweight, with an 1/4 inch plywood floor. It’s designed to use the existing hanger bolts for the black water tank for its port side and you can use J bolts to hook onto the frame for the starboard side. I don’t have a pic of it down but it should tilt down towards the back bumper for loading and unloading (2 front attachments are eyebolt hinges) and then pivot back up. Gives about 4+ Cubic feet of long storage.

Additional Leaf In Rear Springs  Thanks to Bruce Matlack  matlackwindsurfing(at)

The additional leaf in the rear springs idea by the local chassis shop is a winner!  Ride softness is no change, but the tracking improved immensely.  I really notice it when I doze off and run off the pavement!  She comes back nicely without the swaying and rollover threat.  Better in the wind as well.  The spring addition process raised the whole rear end about three inches.  They said it was bottoming out.  I’d say if your courtesy stone skirt is a draggin the pavement, you need a lift!

Macgyver Method of Valve Adjusting For Isuzu Diesels.  Thanks to Pat Shu  patschum(at)

Tools needed: 
1 5/8 inch socket
Pipe wrench
Feeler gauge
Flat blade screwdriver
12 mm box and wrench  (May use open end but it’s easier with the box end)
Small hand mirror, very small hand mirror
Small flashlight
8 mm socket, 10 mm to take the valve covers off.

Take the 8 mm socket and l remove the glow plugs.  This keeps the motor from developing pressure and makes the crankshaft really easy to turn.  From underneath put the 1 and 5/8” socket on the crankshaft nut and find the timing mark on the pulley. Now with your pipe wrench – or big crescent if your big socket happens to have a six point nut on the end – turn the crankshaft pulley until it matches up with the T mark that you cannot see until you put the mirror up above and look back to the motor with your flashlight and you’ll see all these marks in there and one of them is a T and that is top dead center. A bit of a pain in the ass but I think it’s the only way to find exact top dead center on this thing.

Now go pull the valve covers off and you can begin to adjust the valves.  Go to the Northwest Trek Fun Club website ( to get the sequence of valves to adjust.  (It’s in the second of three pages for engine maintenance – Page nine I believe). Depending on which set was loose and then go back down and go 360° with your pipe wrench again and again.  Match the T to the timing mark and finish up the other four valves. Go back and check all the valves one more time and reverse the process and you’re done. If you can get a socket wrench in there you don’t have to use a pipe wrench. But there’s not much space in there.

You only have to pull the three middle nuts off of the valve cover. There is another cover underneath the top valve cover which is the real valve cover and I had to take the top cover off, with the two outside nuts,  to beat the heck out of that bottom one with a rubber mallet to get it to break loose from the top of the head but it finally did. I was able to reuse the old gasket that has been on there for 47,000 miles. It was still in fine shape but it really stuck to the top of that head.

That’s it Bret. Not the greatest technical writing in the world I’m sure but I think it will get the message across. At least two, and I think three, of my valves had absolutely no gap at all – I couldn’t even move the valve. I have high hopes for a better running motor. I don’t know how those valves would have gotten that tight. I believe the valves are supposed to get looser as they wear. Go figure.

HWH Leveler System Pump Source  Thanks to Denney Jones  denneyjones(at)

Just some information for you.  If the pump ever needs replacing on your HWH leveling system I have a source.  HWH will tell you it is obsolete and no replacement. However after extensive searching I found Northern Hydraulics Inc has a replacement pump. Only difference is instead of the post being on top it is on the end. The Tech told me HWH had them made that way so people would be forced to buy from HWH. The cost of the new pump is $200.00. The part number for theirs is 08053 made by Monarch.  I have found Chinese pumps for $90.00 up but many differences so be careful. HWH said a pump would be about $400.00. Original equipment pump is a Monarch.  Mine started refusing to shut off until tapping with hammer. Your system is the same as mine. HWH 110 Series 3 Lever System.

Overheating Trek   Thanks to Ken Harmon (past editor of this newsletter) isuzutrek (at)

For years our dash engine temperature gauge stayed midway in the normal range (white band) regardless of the outside air temperature or the terrain. Around 100,000 miles the temperature became erratic and I replaced the thermostat and it corrected the problem. It was replaced again at around 200,000 miles. Now the thermostat has been replaced for the third time as we passed 300,000 miles but the cooling remained erratic.

The temperature would run higher than normal in hot weather and would go up close to the high mark when we went up hills. Isuzu service in Salt Lake City thought the fan clutch could be the problem and it was replaced. With the new thermostat and fan clutch things improved but climbing hills in hot weather still caused the temperature to run hotter than normal.

While working on the fan the service people checked the radiator for air flow restriction by using a flashlight to look through the radiator fins and they thought it looked ok. Later in Billings, MT, I talked to an Isuzu service manager who asked me what part of the country I was from. He said if you operate a lot in the southern states radiators tend to clog with a mixture of black tire dust and petroleum (oil & grease) that will gradually block the airflow through the radiator. He suggested cleaning it with Simple Green. I cleaned it twice spraying full-strength Simple Green from a hand spray bottle (do not use a pressure washer) through the fins from front to back and then rinsing it out with a garden hose.

Prior to cleaning the radiator, I noticed the bright aluminum screen wire that I had installed over the radiator and inter-cooler years ago was now covered in a black, almost sticky, deposit. After the cleaning was completed the screens returned to their bright aluminum color. Engine temperatures improved again but in some conditions the temperature followed the contour of the land, uphill hotter, downhill cooler, tailwind hotter and headwind cooler.

When I got home I cleaned the radiator again front and back using Simple Green applied with a weed sprayer to get better penetration . Since it was time for new coolant, it was drained and the system flushed. I decided to clean the inside of the system using a commercial cooling system cleaner following the instructions on the container (it foamed a lot as it cleaned). New coolant was installed. While working on the system I discovered several problems with the wires going to the temperature-sending units in the area of the thermostat housing (crispy insulation and broken wire strands). It looked like the original tie wraps intended to support the wires had failed, allowing the wires to vibrate and flex. I ended up replacing three sending units: Engine Temperature, Thermo Sensor and Thermo Switch.

While the grill was out I enlarged the opening in the front fiberglass cap (1.5″along the bottom and 1.25″ on the left side) to allow more ram air to enter and added some baffling in the engine compartment to direct the air flow toward the radiator. To help troubleshoot the system I added a second gauge that shows coolant temperature leaving the engine. Test driving the Trek on a 95 F day, climbing a 6% grade for 4 miles, showed the dash temperature gauge holding steady at mid-range (+ or – 1/8″). The secondary gauge showed straight and level ~ 180 F and mountain climbing @ 8,500ft showed a maximum of 205 F. All temperatures seem to be in the nominal range again.

Information from the service manual shows: thermostat opening temperature, primary 176 / 183 F, secondary 181 / 189 F, full open 203F, max continuous operating ~ 190 F. Fan engage 165 / 190 F & locks @ 2500 rpm.

Writers comment: There are times when engine temperatures do odd things in our Trek. When you test a Trek thermostat moving it in and out of boiling water on the stove you will find it moves very slowly, maybe slower than the engine heats up when you climb a hill first thing in the morning. But to make the overall cooling system work the engine needs to heat the coolant and send it through the thermostat to the radiator. The radiator needs to heat the air that hits the front of the cooling fan where it activates the bi-metal coil and moves a valve inside the fan that compensates for thermal changes of the viscosity of the silicone fluid inside the fan, which in turn changes the speed of the fan and hopefully controls the temperature of the engine. They also talk about the Fuel Low Cut Function which restricts fuel flow by 5% at 208 F and above by reducing fuel flow (heat energy) entering the engine. No wonder strange things can happen.

Raising Your Right Mirror   Thanks to Greg   grrreaat(at)

Many of us have wanted to raise the RH outside mirror, here is how Greg did it, just needs a longer center bolt.

I found these knurled inserts, no clue what they were originally used for but they work!!


High Tech Anti Siphon for Fresh Water Tank  Thanks to Greg  grrreaat(at)

After coming to my senses I had an epiphany…

Someone on TT had the idea of a simple tiny hole drilled in the overflow vent line and they got roundly jeered for it.

Any real siphon breaker needs to raise the height of the run from the tank as well so…

Solution version 3:

Raise the vents run, U-turn and provide enough atmosphere to break any suction on the back side of the turn.

I used a T on the back side of the U turn and made a little closed “tank” that should trap air when filling normally.  If it ever gets clogged with water I put in a little straw to break the water clog.

Had to use hard PEX piping to make sure the lines don’t kink up over heat and time.

Editors note: The Isuzu 2400 and 2830 fresh water tank which is located in the base of the wardrobe will siphon off some gallons of water when filled to 100% and lose even more when subsequently driving down the highway shortening your boondocking time. Installation of an Anti-Siphon device will prevent this. Another method is to use an anti-siphon device normally used in your stick house for a dishwasher installations. Not sure of the tank locations in other floor plans, but if you have some overhead room this will work.

See Level II Tank Gauge Upgrade  Thanks to Bret Medbury  islandduo(at)

We have all fussed with tank gauges, especially black tank, that become erratic and inaccurate due to deposits collecting on the sensors. I had previously tried Horst brand sensors that claim to eliminate the problem and to be blunt, they lied.

To cure this nuisance a See Level II system was installed. I ordered it from RV upgrades ordering the 709-P3W unit which monitors all three tanks, propane and contains the water pump switch. Garnet 709-P3W SeeLevel II Tank Monitoring System ( plus I ordered a sender for the propane tank level, model G14845 RV propane tank gauge, which replaced the original visual only gauge.

Sender strips are fastened with self adhesive to the outside of the tanks so nothing can foul them. The Isuzu black and gray tanks had a raised ridge about mid-line which I smoothed somewhat with a Dremmel Tool. Each strip is coded as to its location for the readout. After all is final and testing is complete the senders are sprayed over with spray can undercoating for protection from the elements.

Install was fairly simple as original sender wiring can be used. The wire from the fresh water tank needed to be snaked to the outside to join those from the other tanks (one wire is used for all three tanks and a new wire snaked down the fridge vent stack area to the propane tank). The readout panel fit the original panel location perfectly in width, but was about 3/8” short vertically. I cut a piece of sheet metal painted black to fill the gap, see photos.

These things work GREAT. They read in 2% increments and react instantly. If you hit the readout immediately after stopping you can see the water slosh in the tank.

I really hope you all enjoy the Isuzu Infoletter.  Remember these pieces are written and submitted by Isuzu owners just like you. You too can submit ideas, repairs, modifications, etc. etc. to be included in the next Infoletter. These can be submitted ANYTIME to me at islandduo(at) and I will save them until I have gathered enough, and a little rainy day time, to publish another.

FYI the Next annual Trek Gathering in Quartzsite, Arizona will be in a new location featuring much improved connectivity to wireless services. It is also much closer to the big tent falderall so you folks on bicycles or even walking will find it more user friendly. Directions, information, etc. will be published on Trek Tracks when we get closer to the time. Circle the date robustly as we will gather “officially” (is there anything really official about Quartzsite?) on January 20th, 2022 thru the 23rd. We are looking for as many as possible to arrive early just to show occupancy to the new area. As always you are welcome to, and many traditionally do, arrive early and stay late. No cost, no reservations, no fuss, no bother, just great Trekkers and Treks.

FYI x 2; I am still hanging on, but with a limited selection of LEDs to inexpensively upgrade your Trek making it more energy efficient, cooler, and be more kind to your batteries. In addition I also have “glow when they blow” fuse assortments. These little buggers can save you much time in looking for that blown fuse. Please contact me about any of the above.

Thank You for reading, please remember to submit material to benefit other I-Trekkers.

Bret Medbury, Editor