Among a host of other problems my bus (GMPD4106) wouldn't shift into reverse. For those of you who have the GM buses with a solenoid that helps select reverse here is what I found.
I took the solenoid apart and cleaned in which DIDN'T seem to help. But what I discovered is that the solenoid plunger was too close to being fully engaged when the bus was in neutral or another gear. I'm not sure if it wouldn't pull the trans lever far enough to go into reverse or the plunger was too far into the body to be activated.(its hard to push the reverse button from the drivers seat and watch the plunger action at the same time by yourself. So I adjusted the linkage to give the plunger more "throw"( i.e. moved the lever closer to the trans lever) . At any rate it works fine now.
Hope this may help someone else. There is nothing like being at a campsite blocking the road with other RVs trying to get by and you can't back up.
Regards
Fred
If memory serves sometimes having 40 foot long arms and hands did not work. What we did if that recalcitrant reverse gear did not want to engage we would kinda help it by abusing things.
We placed the tranny in neutral then let out the clutch, letting everything spin inside the transmission. Then we would quickly stab in the clutch THEN quickly hit that reverse gear button.
While grinding the tranny into second. If we heard horrible grinding noises we were doing it non correctly but sometimes it allowed the solenoid to engage reverse instead of second gear.
If that did not work then we put the tranny in first and pulled forward just a tad, then repeated the above abusive action. This procedure was advised by the master mechanic.
If that did not work we repeated the abusive technique while still slightly rolling forward. Most of the 4106 GMC buses did not have a problem. One did. A bad technique but it worked.
Also we tried to never be in situation where we had to back up.
"If that did not work then we put the tranny in first and pulled forward just a tad, then repeated the above abusive action. This procedure was advised by the master mechanic"
This was the method I was using at the campground.However, after each attempt I was a "tad" closer to the edge of the bank. Finally I got out and put a block in front of the wheel to prevent aforementioned forward motion. At least that part of the exercise was successful.
I had that with a work bus. I just ran the gear selector right the way to the top and the bottom then selected the correct gear. Occasionally you just have to shut the engine off and restart in order to go from drive to reverse. Simple.
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