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Letter 28

Isuzu Trek Owners Infoletter #28

Side decals and roof repairs

Clark and Jeanne Van Galder (clarkvg at wrote-

We have decided to upgrade the interior of our Isuzu 2840 Trek. We plan to re-carpet and use Pergo type flooring in the kitchen and bath area. We also need to do something to the ceiling; it is drooping a bit and has a little discoloration from water stains. We have fixed the leaks.

I should also mention that we replaced the green strip on the outside, leaving the gold strips. It came out great, made a big difference. I went to a sign company and they ordered a roll of vinyl and covered the old strip and saved the lettering so it looks original. $300 is what they charged.

My question to you is how is the ceiling/roof constructed? Have you or do you know anyone who has replaced their ceiling that may be available for some guidance?

Editor – the reply email had the following information on roof construction and pictures of a roof undergoing repair.

When I toured the factory years ago (1994) I seem to remember the top to bottom roof construction was:

-Fiberglass sheet that has a sun-resistant additive in it. I have seen material that looks the same in old public restrooms but someone told me that type of material did not have the sun protection.

-A relatively thin plywood top sheet similar to the plywood on the inside walls of the Trek.

-The roof joists (slight curve on top and flat on the bottom) were cut out of a plywood type material and span from one sidewall across the coach to the other sidewall.

-Several kinds of brace wood to space the roof joists.

-Fiberglass batting for insulation.

-Relatively thin plywood interior ceiling covered with the headliner material.

As I remember it the entire roof structure is wood; later Safari Treks had a foam core between a top and bottom sheet of plywood. Metal came with Monaco.

Blind replacement, converter, power steering fluid, headlights & transmission.

Keith & Jody Redfern (kjredfern at sent the following information-

Dear Ken and Cathy: Thanks for all your work on these Infoletters. We hope our contribution will be helpful to other Isuzu owners. Last fall we took a 9,000 mile trip to the Pacific coast and back. In order to get ready for the trip, we made several modifications. The first thing was, we replaced the blinds in the front driving area. We removed the pleated blinds that had become a constant aggravation with sticking, etc. I found out that Home Depot’s roll blinds came with spring-loaded ends, which enabled the blind to remain in place after hitting bumps or having vibrations, so we installed roll blinds in the front windshield and on the side windows. We made wooden mounting frames for the end brackets and attached them first. We also soldered a piece of paper clip across the opening on the bracket that would have enabled the roll blind to jump out of the bracket. The opening is not necessary with a spring-loaded roll blind. This worked out very well for a reasonable price.

We removed the front TV that is located above the driver’s compartment. In the hole where the TV was, we put a small safe we purchased at Harbor Freight for about $50. Inside the safe we drilled two holes in the back that line up with a box member that runs horizontally across the front structure of the coach. We then mounted the safe through those two holes with self-drilling metal screws. The safe is digital and just big enough for storing small valuables that would be a target of a smash-and-grab break-in. There is enough room ahead of the safe to put a decoy panel or store other small, lightweight items, and we installed a small curtain. This made a difference about not having to hide stuff, and would stop an amateur, (but not a professional), and served our needs. In order to overcome the loss of the TV and the back-up camera, we connected the feed wire from the back-up camera to an LCD 6″ flat screen unit, that works off a 12 volt converter normally, wired it to 12-volt system and installed it in the space to the immediate left of the dashboard. That worked well. We overcame the loss of the TV by buying a 14″ flatscreen LCD TV with a built in DVD player which we store while traveling and use wherever we want in the motor home.

In a previous trip to FL, we burned up our converter which is mounted in the rear compartment. I felt that the compartment was not ventilated, and in hot weather the unit overheated. I installed two louvered household vents using pop rivets and painted them to match the exterior colors on the door to the compartment. Underneath the vents, which came with built-in screen, we drilled multiple one inch holes and placed the vents over them. I feel the lower temperature in that compartment will lengthen the life of the inverter and converter units. Editor note – water and moisture in the inverter compartment can cause problems also.

Inspecting the power steering fluid in the p.s. reservoir, I found it was very contaminated and needed changing. In order to change the fluid, the return line to the reservoir should be taken off and the reservoir fixture plugged and the hose put into an open container. Fresh fluid, approx. a gallon of Dextron, should be on hand. The lid and the oil strainer should be removed from the reservoir and the engine started at idle, with the front wheels off the ground. Oil will immediately pump out of the return line. While oil is flowing out of the hose, new oil should be poured into the reservoir at approx. the same rate, while someone turns the wheels to the left and then back to the right. Continue to flush the oil through the system until the oil runs clean out of the hose. At that point, shut off the engine, reinstall the hose on the reservoir, wash the filter in mineral spirits and allow it to dry completely of solvent, and reinstall in reservoir. Fill the reservoir to the full line and reinstall the lid.

Our experience with changing oil on the road and lubricating the chassis during long trips is that it can be very expensive if it is done at an RV service outlet. Walmart seems to want the RV business, and their auto centers accommodate motor homes very well. The problem we encountered was they do not stock oil filters for the Isuzu and they usually do not have access to them. We have found that the larger Isuzu factory filter requires tightening more than the aftermarket filter by a half turn. Their people do not know there are two filters (oil @ 6,500 mi & fuel @ 13,000 mi intervals) and you must provide them, plus instructions for installing. You can provide your own oil, if you wish. They remove the cost from your bill, which normally includes a filter and oil. If, upon going to Walmart for an oil change and a grease job, you provide them with a schematic of grease fittings for the vehicle and instructions for changing the filters, the staff will do a good job. They will not, however, check any other fluid levels or check tire pressures unless you specifically ask them to. Your savings in costs are at least 50% or more if you think ahead before taking it to them.

We also have had bad alignment on our headlights due to adjustment screws pulling out of the metal housings due to the poor design. I decided to take out all the headlights, replace all the adjustment screws and realign our headlights with an old sealbeam alignment tool that a lot of shops still have for older vehicles. We had a difficult time with the alignment and also realized, from a previous letter, that we weren’t the only people who had problems with this design. We made modifications without having to re-fiberglass the housings and have some holes in the housings so adjustments can be made properly. After completing work on the headlights, I attached one-gallon freezer bags above the headlight housings and let them hang down over the wiring and the holes to keep road splash, etc. from getting into the housings. So far, so good.

While on our trip, we were in WA state when our transmission started to drop out of overdrive and go down to 3rd or 2nd gear without warning. I knew from previous publications that this was something that could happen and solved it by pulling off the road and shutting everything down to allow the computer to de-bug. We did this and it worked. Everything worked great until a week later, we were on the Pacific coast in northern CA and the same problem started to occur. We would shut it down, and try to continue, and it may or may not have cured the problem. We knew at that point that this problem would not go away by stopping and starting.

I checked the transmission temperature and it had started to run hotter when this condition existed, due to running in lower gears. The oil in the transmission had been completely flushed and changed previous to the trip, and was in beautiful shape still–no sign of anything wrong. Through connecting with my daughter I asked her to look up qualified Isuzu dealers that we could seek help from for this problem. I contacted Victory Auto Plaza in Petaluma, CA and we made an appointment and limped to it. The transmission would clear the problem at times and run normally, then suddenly act up again. They were an Isuzu authorized GM dealer but they failed to diagnose the problem and sent us to Oakland, CA, to TEC of California. They also failed to diagnose the problem. The transmission would sometimes give us a day or two with no problem, then start up again.

I woke up one morning and remembered that I had an old parts catalog for Isuzu trucks from a company who specialized in Isuzus, in Santa Ana, CA (a suburb of Los Angeles). It was Tom’s Truck Center (714-338-6030). They said they could diagnose it and fix it. We just had to get there. We then limped along to LA, and eventually made it to Tom’s. I, meanwhile, had removed the glove compartment in the dash to reveal the computer that controls the transmission so that Tom’s would have easy access to diagnose the computer. Upon their getting the vehicle, I learned that this truck center not only supplied parts across the country for Isuzus and many other trucks, they are also a recycler of used components for Isuzu and have a vast inventory. They tested the computer and found that it was failing, and replaced it with a used unit for a very good price. A new computer costs over $1,000.00 plus labor. They diagnosed, repaired and replaced the unit, gave us a discount out of courtesy and the total cost was $825.00 out the door. We would recommend this company for parts, used or new, to the Isuzu Trekers. They are outstanding to do business with and they know what they’re doing.

One thing that may be causing a problem with our Isuzus is heat around and in the transmission computer. They found a connection to the computer where the plastic insulator had melted. If you have a full glove compartment, it may restrict ventilation and allow heat to build up. I am going to add either a computer fan or relocate the computer to an area where there is more ventilation.

We think our Treks are really a great solid vehicle and I can’t tell you how many people stop to admire our 19-year-old vintage coach. Sincerely, Keith & Jody Redfern

Editor- Thanks, Keith & Jody, for your input. Replacing power steering fluid is a scheduled maintenance item. If the fluid becomes black or starts to overflow at the reservoir your power steering pump seal has failed, allowing engine oil to enter the system. See Infoletter #15

Exhaust manifold, cruise control

Ken Harmon, (isuzutrek at

The Trek is back from the shop after the 3rd exhaust manifold repair in 230,000 miles. A little history; my first problem occurred when one of the exhaust manifold bolts backed out and was lost. I think the second problem occurred when one of the bolt heads popped off, this time it required removing the manifold to make the repair. When the manifold was inspected one crack was found above the turbo mount area and three cracks below. With the installation of a new exhaust manifold I had studs installed in the former bolt locations, two in front and two in the rear. My thinking was, if Isuzu thought studs were good in the center part of the manifold (and I had no problems with them) why not install them in the other locations.

When they removed the manifold this time, the lower forward stud had broken off flush at the exhaust port on the head. As they were removing the nut on the upper forward stud it broke also. Normal shop policy was to replace all studs when the manifold and turbo were removed. I elected to go back with studs in all exhaust manifold mounting locations. On our RV it looks like the service life on exhaust manifold attaching hardware, bolts or studs, is about 75,000 miles.

Cruise control

Over time my cruise control began to drop out when we hit a sharp bump in the road. “Resume” brought it back with no problem. As time went on it took less and less of a bump to make it drop out. One of the first things I checked was the setting of the brake light switch; it seemed OK. I have had problems with corroded wire connections at the cruise servo and occasionally a wire would come off one of the posts.

As the “drop out” became worse I resorted to shock mounting the servo but that did not help. Finally, I rechecked the brake switch and it was now definitely out of adjustment. I think a contributing factor was the return spring getting weak over time and allowing the pedal to “bounce” when I hit a bump. Cruise works good now.