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Letter 33

Isuzu Trek Owners Infoletter #33

November 2013

Bruce Matlack, (matlackwindsurfing at, 1994 2400, 133,000 miles.  Remember to replace “at” with @ in the email addresses.

Front Wheel Bearings and Brakes.

Pay attention to the wheel bearing maintenance schedule! They are not sealed as on your car. I almost had a truly bad bearing event because I was way over on the wheel bearing packing scheduled maintenance interval. Also found one brake rotor to be glazed and full of cracks; it needed to be replaced immediately before it disintegrated. The first pads lasted to 80,000 miles.

Floor insulation.

On top of the carpeted area over the engine lid I added some high density, 1-inch thick home construction insulation.  It really helps keeping the heat and noise down.

 Mice invasion.

I finally got serious about blocking the remaining openings used by rodents to enter the coach.  Areas to pay attention to are under the bathroom sink.  Look for openings near what looks like sewer pipe and the vent pipes for both black and gray tanks. I used the common spray foam one gets at the hardware store together with steel wool imbedded in it where possible. Otherwise, I just wedged the steel wool in tightly. It is tough to access these areas, especially if you are a normal-size person. The most difficult area requires removing the fuse panel below the bath sink and doing a lot of stretching and cursing. Don’t forget the far corner of the pots and pan corner cupboard. The gray water vent pipe opening is in the far corner and very difficult to reach, but do it! Previous newsletter dealt with screening off the floor level air inlet below the blower motor on the right side of the firewall.  Metal wire screen will let air move in, but not rodents.

 Thermostat erratic behavior.

For no reason, the thermostat was allowing an unusual temperature rise above the half-way mark. Then it would behave normally for 1500 miles or so, then get radical again for no apparent reason. I changed the thermostat and cured the problem and possibly saved my engine plenty of damage.

Alternator wire.

Problems with the main hot wire from alternator to the isolator. This big thick wire has cost me plenty over the last few years, probably at least one alternator and two batteries that did not need to be changed. It gets corroded down where it comes off the alternator, and is incredibly hard to reach. The lug at the alternator is where the problem mostly occurs. Best to change out the entire wire and connector lug so that resistance is held in check against false readings of bad batteries and/or bad alternator.


Editor Note: We could be seeing a trend here – seems like we have multiple reports of problems with thermostats and wire terminal ends at the alternator.  Might be worth watching on our coaches.

 Water heater replacement. 

Ken Harmon, IsuzuTrek at, 1994 2400, 260,000 miles.

Taking a shower one morning I noticed the water pump was running more than normal; I thought a faucet must have been leaking or the pump was failing.  After breakfast I went outside and found  water coming out all along the left side of the coach.

I pulled the drawers and panels under the cabinets and opened the furnace compartment.  There was up to ½”  of water standing along the interior wall.  I could not see any obvious leak at the exposed gray plastic pipes or around the water heater.  We soaked up all the water we could with rags and found new water was coming from the area of the water heater or the pipes located under the water heater.

I disconnected the two water pipes at the back of the heater and went to town to buy caps and plugs so the water heater could be capped off and the water pipes plugged so they were separate systems. I drained the hot and cold water pipes at the low point valves and siphoned the water out of the heater.  With the systems isolated I pressure-tested each system using my tire air compressor.  The pipe system did not leak.  Pressurizing the water heater gave us a hissing sound coming from inside the heater insulation.  Apparently the water tank had rusted through so a new water heater was ordered and was installed by a local RV repair facility.

Unfortunately the mechanic assigned to the job was not experienced with water heater installs  and elected to not follow the manufacturer’s instructions.  He did not center the unit in the wall opening, align it perpendicular to the wall, seal it around the edges or use the gas pipe grommet to prevent propane and/or exhaust gases from entering the coach. I will need to reinstall the unit properly.

The coach ended up with a lot of residual water soaked into the particle board floor, along the wall and in the heater ducts.  We addressed this with a fan, a portable electric heater and running the furnace with the windows open.

 Transmission replacement.

Our travels took us west through central Nevada and up the Pacific coast toward Canada.  At a stop in central Nevada I found a significant oil leak coming from the rear crankshaft seal with oil dripping out of the bell housing.  By the time we reached the Reno area the oil leak had cured itself.  I  stopped at FMI in Portland to talk about the problem.  It would cost about $1,000 to remove the transmission, install a new seal and re-install the transmission.  We also talked about the expected service life of the transmission, which is around 170,000 miles, and the cost of a re-manufactured transmission.  Our transmission had close to 260,000 miles on it.  I decided to head on to Canada and if the oil leak returned we would come back to Portland to replace the seal and the transmission.

On our way north of Seattle I noticed a different noise and vibration in the drive train.  We stopped in a campground where I jacked the coach up, ran the engine and drive train and found nothing wrong. When we departed the last campground before entering Canada there was a big “thump” and the engine stalled.  I checked the transmission oil; it looked good and did not have a burnt smell.  We drove to town where it went “thump” again and this time the coach did not want to move.  I called a friend (thanks, Dick) and he reminded me to check the transmission failure codes through the transmission warning light system and try pulling fuse  #11 to reboot the transmission computer.

The light gave me a failure code 35 – the service manual said this was a line pressure valve problem.  I called Fleet Maintenance (thanks, FMI) in Portland and they felt I had a significant transmission problem even though the fluid was still clear and it did not have a burned smell.  I decided to head back to Portland where a re-manufactured transmission was in stock.  About an hour down the road the transmission dropped into the “safe mode” and was showing a continuous flashing warning light.  We stopped at the next exit, turned the engine off, re-booted the transmission computer and started out again but this time there seemed to be a significant loss of engine power getting to the drive wheels.

Traveling south through Seattle in rush hour traffic the Trek stopped in the middle of 6 lanes of traffic.  By repeatedly turning the engine off and on, rebooting the computer and cycling the shift lever, we were able to get the coach to move short distances and eventually we were able to get the coach to a parking lot.  Another check of the fluid showed that it was now dark and it had a burnt smell.  We ended up getting towed to Scarff  Ford/Isuzu in Auburn, WA, where we ordered  a re-manufactured transmission and had it installed.

I wish I could say this solved all our transmission problems but on the way back to Albuquerque the  transmission gave us a few codes and after a short stop in our driveway the coach did not want to move into our storage area.  The good news is: Isuzu re-manufactured transmissions have a one-year parts and labor warranty.


Editor Note: This is why I like the Infoletters, see the next input from Keith & Jody

 Transmission computer overheat.

Keith and Jody Redfern, kjredfern at .

HI, Ken & Cathy.  We added a feature to our Trek this year: it is a 12-volt desktop fan underneath the transmission computer that is located under the glove box.  It is wired to a circuit that is turned on by the ignition switch. We know from experience that in warmer weather our original computer got too hot & acted erratically. Having a full glove box over the computer seems to keep the temperature too high, so we are trying to help move some heat out of that area. So far so good! We look forward to your news about your summer adventures.

Keith & Jody.

Thanks for the input and guess what I will be working on soon!  Ken & Cathy