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Letter 22

Isuzu Trek Owners Infoletter #22

March 2008

Interior Re-do

Bonnie Denning (kioti3 at )writes:

Encouraged by the great results other Trekers have reported we decided to redo our 1992 Trek.

We began with removing the carpeting in the living area, kitchen and bathroom. I then sanded some high areas, filled in with auto body filler, and varnished all of the original flooring. Next we installed a laminate brazillian cherry flooring in the living area and the kitchen.

My husband did not feel up to installing new vinyl in the bathroom so we had that done when a new china toilet was installed.

I purchased oak moulding, & stained them to match the flooring. We are very happy with the results and look forward to installing new carpeting in the area where the driver & passenger sit. I will also be redoing the walls, but have not yet made a decision as to what I should do.

Lyle & Bonnie Denning

1992 2830 Isuzu

(Editor Dale: We re-did the walls with fabric very similar to the stuff that is on the ceiling. It was easy to work with, added a bit of insulation-sound proofing and Trish discovered she could easily hang pictures on it, and easily change them, by using the hook side of velcro on the picts and other deco items. We took a two day side trip in our toad while the glue dried and its smell went away.

 Transmission acting up? (Inhibiter Switch)

Len Nicholas (

nicholas146 at gives us this good info:

We have all heard the remarks about our transmissions suddenly acting up. The solution in a lot of cases was to pull over to the side of the road, shut the motor off for a few minutes to reboot the tranny computer. Start out again and all was well.

I too had this problem. Suddenly the unit would downshift for no reason at all or act very odd in it’s shift patterns .

I discovered that one cause of all these remarkable actions is a little known switch that operates the transmission. It is called an ” INHIBITOR SWITCH”. I have replaced this switch, it cost me about $85.00, and the transmission works like new.

The Inhibitor switch is located on the passenger side of the Transmission body. It is most easily found by having someone move the shift lever while you get under the motorhome and watch where the linkage connects to the transmission & also the switch. These two points are the same. The switch is behind the shift lever and is a very tight fit in its little recessed space on the side of the transmission. This is why it is missed so often. If you did not know it was there it would not be noticed at all. Many wires come out of this switch and are covered with a 1/2 protective covering. All of this terminates in a plug that fits its mate that is easily seen.

Holes at two points on the case are used to align the switch with the transmission in neutral. A rod is inserted into the holes and the switch body is shifted until the all holes line up then you simply tighten the mounting bolts.

Once I got the old switch apart on my workbench it was very apparent exactly why the transmission was failing. The unit has a copper wiper that contacts different copper segments on a plate. As it wipes these different segments it sets up the shift pattern. In my case the copper wiper was black with corrosion as were the segments .The result as we all know was an erratic shift pattern.

Those of you who are very handy could dismantle this switch & use a little crocus cloth to polish the contacts.(Editors note: this is a great ‘field fix’ or, in Len’s case, he now has a spare switch (if he can remember where he put it, a few years from now when it happens again!)

(Editor’s note: Len has photos of the switch. If you need them please contact Len.)

 Exhaust Manifold bolts and dipstick tube leak

Bob Gilson (bobgilson at shares:

Thanks for the reminder and opportunity to contribute to the letters. I enjoy the letters and print them for reference.

Recently while traveling I could hear a somewhat unusual engine noise and figured is was an exhaust leak. Sure enough one broken bolt and a missing nut at the rear of the engine. I believe someone else recommended checking the exhaust manifold on these Isuzu’s. I did look at them a while back but didn’t notice loose bolts. While moving parts around to be able to get to the bolts I decided I needed to remove the dip stick tube. In doing so I found the upper end was leaking oil where it passes though a mounting bracket. On mine the dip stick tube is routed through a flat bracket without a bushing. The tube has worn through on the bottom so whenever I check the oil enough falls off the dip stick to seep out a hole worn into the tube. This wear spot is located under the hood. There is a bracket about three inches long and an inch wide. Apparently the manufacturers drilled a hole in the bracket and pushed the tube through. Certainly not a major problem but it would be a nuisance if it leaked and dripped down onto the alternator. I’ll probably repair it by putting rubber fuel line over the worn spot and securing it with hose clamps.

My Trek (a 91-2830) now has over 140,000 miles and is running strong. We bought it about three years ago with 70K miles. After purchase I added new front shocks, Sate-t-Plus, tires, front wheel bearings, propane infusion, boost, trans temp and exhaust temp gauges and probably other items that I don’t remember at the moment. We have done two trips around the US, one to Alaska and numerous trips to California and Texas from out home in Oregon. Great vehicle, great economy as all of Isuzu owners know. I just added new Bilsteins to the rear and handling and ride has improved. My wife noticed the difference in sounds or more accurately the lack of noise of the stove grill bouncing with each bump.

Thank you for doing the letters – sorry to hear you are passing it on but I’m confident Keith & Jody will continue your good work.

Skylight Replacement and Request for Isuzu chassis manual

Linda Dahle (lindadahle at writes:
Hi Dale,
Thankyou for doing the newsletter, I learn so much from it. This time I have two things. First, my skylight wore out. It was just leaking and then filled up with water. I had my RV repair shop check into skylights and I guess there has been a change in the industry because the only known supplier wants $400 and will then custom make one. Well, not to be discouraged, I took off the old one and it wasn’t really custom just a double layer plexi with some alumium and gasket holding them together this was screwed to the roof and caulked around. The inside of the skylight was no higher than the roof, so I caulked a piece of plexiglass over the opening large enough to cover the old nasty screw holes. I cut the plexiglass to fit with a circular saw and it did a great job. This spring I plan to cover that piece with another plexiglass sheet that is more expensive and guaranteed not to break, purchased at Lowe’s. I plan to put a heavy rubber gasket between to get some dead air space and perhaps some insulation value and will drill and screw that piece down. I think this will be quieter going down the road and definitely more leak proof with a total investment of about $60. During extreme heat or cold I block this opening on the inside with a pillow, a piece of tagboard and 2 small bungle cords hooked onto the trim. Sounds ugly, but looks like it belongs.

Second, I am looking for an owner’s manual for the Isuzu Chassis for 1994. I have the little pamphlets for the rv part. If anyone has one I could copy or knows were I could get one, that would be great.

Ken Harmon has been a frequent contributor to the Infoletter ever since the very earliest issues.

Welcome back, Ken! The following three items are from Ken (Kencathyha at )

Freedom 10 inverter moisture problems

After a 14-hour ferry ride in fog we arrived in Newfoundland at night in a very heavy fog. The fog lifted the next day but by late afternoon it was back and we could no longer see to drive. We stopped in a pullout on top of a ridge and by nightfall there was a heavy, horizontal wind-driven rain.

I elected to turn the back of the coach into the wind to cut down on the noise; this may not have been the best decision. (Previously I had resealed the center brake light and installed additional weatherstripping around the aft door.) The rain lasted most of the night and when we got up the next morning the inverter would not stay on. It would go through the start-up cycle but trip out on high voltage. Then we noticed the refrigerator, water heater and furnace did not work. Fortunately the generator worked so we could get the bed up.

The weather improved during the day and the water heater and furnace started to work. We did not have electric hook-ups at our next camp and the inverter and refrigerator still did not work by the time we went bed. The next morning the inverter worked and by evening the refrigerator was working.

From that point on, the inverter start-up was intermittent depending on what seemed to be local humidity. Along the coast it was intermittent. When we went further inland to dryer weather, it worked most of the time (except on some rainy days). Later, when we went to the west coast and camped close to the beach, it started having problems again.

At home I removed the inverter. The dust on the topside of the case showed a little water had dripped on it, but not much. Inside I found that everything was covered with a moderate amount of what I would call “coarse dust”. The top circuit board, the one that is installed with the printed/soldered side up, had the most dust on it.

My neighbor, who worked with electronics controls in steel mills, said he had seen a lot of problems with circuit boards that were exposed to dust and moisture. He suggested cleaning and silicone spray. With compressed air I blew out all the dust I could from the unit but the circuit boards retained a fine dust covering. I purchased silicone spray from a local electronics store and, using a soft bristle brush, I sprayed, brushed and rinsed the boards with silicone. I blew out the residue and then applied two coats of silicone, allowing it to dry between coats.

I fabricated and installed a drip shield over the inverter prior to reinstalling it. I am writing this more than a year later, on the coast of British Columbia in the rain, and can report we have had no additional problems with the inverter.

 Speedometer/Cruise Control

(Another from Ken Harmon-see his address above)

Approaching 190,000 miles on our ‘94 Trek, the speedometer gradually started to fluctuate in the 50-60 mph range. When the fluctuations became significant it caused the cruise control to surge. I tried lubricating the cable using several different lubricants, 3 in 1 oil, Dextron III, and silicone spray. Each time I removed the cable assembly from the transmission and added the lubricant at the cruise control end. By blowing on the cable I could force lubricant through until it came out the bottom end.

The lubrications worked for a while but each time the interval shortened before the problem re-appeared. Looking closer at the cable I found it was made in two sections with a coupler in the area of the front axle. By jacking up the coach and running the transmission/drive line I determined the problem was in the area of the coupling. On the recommendation of a speedometer shop I disassembled the cables, cleaned each component, greased it with light grease, and tried it again. It improved some but still caused a surge in the cruise control.

I had the speedometer shop fabricate a one piece cable using new parts from their inventory. They lubricated the cable using a light lithium grease. I installed the cable and found the coupling nut at the transmission needed to be shortened (by grinding) so it would hold the cable housing tight against the fitting on the transmission. I have several thousand miles on the new cable and it is working fine.

P.S. On a recent trip in 10 degree F weather we did experience some surging but it cleared up as soon as we reached warmer weather.

Norcold refrigerator problems

(Another from Ken Harmon-see his address above)

On a recent trip we started to notice problems with the refrigerator. Driving down the road with the refrigerator operating on gas (propane) it worked fine. In a campground plugged into the electric it worked fine. When we dry camped with the unit set on gas it did not work; however, when we started driving the next day the refrigerator would start working.

When we got home the first thing I did was clean up the burner with a wire brush and blow the loose crud out of the flue. When I tried it the igniter would spark but there was no gas flow. I checked the current at the gas solenoid while the thermostat was calling for cold. (To make it call for cold set the switch on “gas” and have someone move the temperature slide switch to a colder setting). The voltmeter showed 12 volts at the solenoid coil but still no gas flow. When I tapped the solenoid with a screwdriver handle during the starting sequence the solenoid clicked, gas flowed, and the burner started.

The sticking gas solenoid valve explained why it would work while going down the road (vibration) but stop working while setting in camp. I checked the local RV supply store and they quoted about $375 for the part. They said the old solenoid number was superceded by a new assembly, it would need to be ordered, and they could not tell me what parts were included in the new assembly. I decided to shop around and ended up ordered the same assembly from Camping World for about $160.

After a lot of effort to find a phone number, I was able to talk to someone at Norcold and was told they provide no customer support. They would not tell me what parts were included in the assembly or give me any service information. Nothing. They said I should contact a licensed gas service technician at one of their local dealers. When I talked to the local dealer they said there were no service manuals available for the Norcold units and they were instructed not to talk to customers about servicing their own units. Apparently the procedure the factory wants to follow is to have the dealer call the factory with information on the problem and they will send information to fix that specific unit.

I went around back and talked to one of the technicians and he gave me the information I was looking for. The new solenoid assembly has a solenoid valve combined with a built-in on/off valve (eliminating the old separate on/off valve), the connecting tube and a new burner. I installed the new assembly, leak checked it with bubbly dish soap, and now the refrigerator is working fine.

Stop and see us in Florence, OR (summer) or San Bruno, Baja California Sur (winter) if you travel that way. Always room for a Trek…full hookups both places. (note: the invitation above applies to all who Trek with an Isuzu!)