Sorry this is so long, but I'm hoping for advice / suggestions and want to provide as much detail as possible:
We've been on the road for a few months, driving on mixed terrain including mountains, with no engine or tranny issues. My 2004 National RV Dolphin LX class A is a gasser on a Workhorse W22 chassis with a GM Vortec 8100 (8.1L) engine and an Allison 1000 tranny. We're towing a Honda CR-V which weighs about 3600 lbs loaded - the motor home is rated to pull 4000 lbs. Per a recent "Smart Weigh" thru Escapees, we are under max GVWR by 400 lbs.
A couple days ago I was driving the motor home (and towing the CR-V) across the Hill Country of Texas. This is an area of rolling hills, but no long or very steep inclines or downgrades. This day was the was the first time since I bought the motor home last August that we've driven in heavy rain with LOTS of water on the road. At times, I was using cruise control with Overdrive turned OFF, and everything was fine until we were about 4 hours into the trip. We were going up a hill at about 60MPH and the tranny tried to downshift to maintain speed, just as it had been doing for 180 miles. But, the tranny would not engage in the lower gear - it "bounced". I immediately turned off the cruise control and then discovered that if I slowly accelerated, the tranny would down shift without an issue... but if I pushed it, the tranny would bounce.
About 70 miles from our destination, the terrain leveled out and I started using the Cruise control again - everything was fine. We are now set up at the RV park.
At the time of the trouble, there were no warning lights illuminated on the dash. The engine temp was normal. Oil changes and other preventive maintenance are up to date. The previous owner had the tranny fluid and filter changed about 16,000 miles ago. Current mileage on the motor home is around 39K.
My questions are:
- What is the correct way to check the transmission fluid level? Do I need to drive the motor home and bring it to normal operating temp and then check the level while the engine is running (in PARK)?
- Is it possible the extremely wet weather (lots of water getting thrown up on the underside of the motor home) contributed to this issue? Is there wiring or electronics that might have been affected by the moisture?
- Should I check the Oil vent (breather) for dirt? Where is it? How to clean?
- Should I get an analysis done of the tranny fluid and change if necessary, or just bite the bullet and have the fluid and filter changed?
- Is there some sort of diagnostic a service shop could run to check the transmission and drivetrain?
- Could turning the Overdrive On and Off have an adverse effect?
- Would disconnecting the chassis battery reset tranny computer/sensors? Is there any point in doing this?
- What else should I do?
We will be leaving in a few weeks for Colorado, and I want to take action now to help ensure we don't run into issues on the road.
Thank you in advance!
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