| Author | Message | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 9 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
I have the Automatic Allison VH9 W/leaktroit diesel. When trying to put it in gear I get just grinding and am having trouble putting it in gear both Forward & Reverse. I have read online that it's a fluid temp problem. (is that true?, and any solutions or adjustments that can be done?) A previous owner installed a transmission gear override toggle switch that allows starting in gear that I read was supposed to allow it to start in gear. (which by the way the toggle switch was not labeled and the buyer I got it from knew nothing about it and it took me days to figure out what the heck it did then another few weeks to figure out why it was on there. FYI I tried that for the first time today and it started in gear but grinded until I popped it into neutral. (I only tried that in Reverse today maybe it works better in Drive??) I just let it warm up another 30min and it worked fine. Dumb luck that it worked or is a temp problem? I've only had the bus for since November and it came from Southern California. The problem seems to be worse but it's much colder now with some mornings in the teens. Anyway since it' new to me and I don't know anything about it I figured I would ask for some other input for people who might know. It drives fine and it only seems to be happening when it's cold. | ||
| Steven M. Toomey (Pabusnut)
Registered Member Username: Pabusnut Post Number: 38 Registered: 3-2005 Posted From: 96.25.34.30 Rating: N/A |
Scott, I had to also put in a neutral safety override switch in my GMC5301 w/VH9(and later VS2-8) as neither would let you put them in gear cold! During winter it is nearly impossible to warm up that Detroit w/o getting it out on the road where you can put a load on it. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 730 Registered: 2-2001 Posted From: 184.0.13.120  Rating: N/A |
I had a VS2-8, not a VH-9 but the basics are very similar. These boxes are different from modern stuff. They actually have a mechanical shift lever on the trans moving mechanical F-N-R gears and then up & down shifting is done automatically. You have to either energize or de-energize a solenoid valve (there are both kinds)on top of the trans valve body to dump hydraulic pressure to allow shifting or it only grinds. Plus, you need air pressure for some that have an air powered F-N-R shifter. Don't mess with this much because when it is grinding, it is destroying the mechanical gears. First thing to do is see if you have a lever and cable going from the front to the trans, or if the shifting is done by air on the trans. If no shift cable, then it should have a shift mechanism with 2 opposing air solenoids & some air switches at the lever on the trans. | ||
| Paso One (Paso_1)
Registered Member Username: Paso_1 Post Number: 201 Registered: 11-2004 Posted From: 142.165.246.240  Rating: N/A |
When I had a VH9 It also had the neutral over ride switch. Only needs to be used when cold once the engine/ trans warmed up it was fine. Best to live with it unless you want to change trans. Loren joplin said it had something to do with a hanging clutch pack that was a GM change up that had that negative result. | ||
| Paso One (Paso_1)
Registered Member Username: Paso_1 Post Number: 202 Registered: 11-2004 Posted From: 142.165.246.240 Rating: N/A |
Sorry Scott I just re read your post. This is how I used the neutral override switch. Hold toggle switch ( returns to middle when released ) start engine in forward let engine warm up in gear. ( park brake on or sit there till all warmed up. Sometimes I just waited till it air'd up and then drove away. If you start it in gear and shift to neutral right away or attempt to move it to reverse from forward it will still grind away. Let the oil get hot ( warm) and you would never know it was the same transmission. (Message edited by paso_1 on December 20, 2011) | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 10 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
I suspect that Lauren Joplin Put this over ride toggle in since the bus came from his collection, but I got it from a guy that bought it from him 3 yrs ago and he didn't know what it was for. I will try it if forward the next time I have problems with it. I also put two of the magnetic 200w warmers on the transmission oil pan to keep some extra warmth in the fluid. Maybe that will help. I'm glad to know it is probably just a cold fluid issue. | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 60 Registered: 3-2011 Posted From: 173.8.221.225  Rating: N/A |
I tied my shutdown solenoid to the gear shift (by accident, as part of the old VH mechanical shifting linkage/wiring mess!) in my TDH-4512 so when I move the shifter out of N F or R the engine starts to die...it allows me to grab a gear real fast and once it's in, it'll fire right back up. Neutral safety start interlock disabled, so in-case it dies I can still fire it back up while in F or R...easy as pie :-) |