| Author | Message | ||
| Brandon Merritt (Brando4905)
Registered Member Username: Brando4905 Post Number: 9 Registered: 3-2009 Posted From: 173.69.74.220  Rating: N/A |
Had some problems this weekend. Trans started slipping in 1st, fluid level good. Then got worse, stopped slipping and now will not shift out of 1st. Bus at Cardinal Coach in Warsaw,NC, really good shop that knows GMC's. They have tried everything short of replacement tranny. Anyone have any suggestions? Oh, just changed fluid to synthetic 1,500 miles ago,changed spin-on filter and cleaned internal filter. | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 280 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
Brandon You mentioned that the shop checked everything. Did they check each clutch port for pressure? If the main pressure is okay, the shifter is working then it is worn clutches. The only other thing is when you changed the internal filter did you check the "O" ring where the filter goes into the valve body. It may have come out and then the pump won't suck oil. DO NOT rev up the engine if the clutches are slipping. They will burn out in seconds. The fricton material is very thin. Bill | ||
| Brandon Merritt (Brando4905)
Registered Member Username: Brando4905 Post Number: 10 Registered: 3-2009 Posted From: 173.69.74.220 Rating: N/A |
Bill, Thanks for the reply. When I left them yesterday they said pressures would be checked next. I mentioned the internal filter seal and the mechanic said he had never seen that happen before. I read about that in an Allison pdf. The morning after the slipping, when cold it shifted fine until everything warmed up. I'm just hoping for the best, need to be back on the road in 2 weeks, and these guys are real busy. | ||
| Don Fairchild (Don_fairchild)
Registered Member Username: Don_fairchild Post Number: 26 Registered: 3-2007 Posted From: 66.17.9.74 Rating: N/A |
Brandon; The first thing I would check is the gov. Take it out and try to turn the fiber gear and look at it and make sure the valve is moving inside. If the pressures are good and the bus does not move very good I would say the stator may have gone out. Sorry I hope this helps. Don | ||
| Brandon Merritt (Brando4905)
Registered Member Username: Brando4905 Post Number: 11 Registered: 3-2009 Posted From: 173.69.74.220 Rating: N/A |
Don, The gov. was the first thing they checked. Moves very good in first gear! Just can't get past first. Thanks, Brandon | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 939 Registered: 7-2006 Posted From: 74.162.82.56  Rating: N/A |
Re: "Anyone have any suggestions? Oh, just changed fluid to synthetic 1,500 miles ago" You don't suppose? I thought I read sometime ago, that of you're using "normal" lubricants, and switch to synthetics, you'll be in for a helluva time.... unless you thoroughly fllush the system... with trannies designed for normal lubricants, I wouldn't dare take a chance. | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 243 Registered: 2-2007 Posted From: 64.12.116.203 Rating: N/A |
I want to change mine to motor oil. Anyone know the recommended procedure? How many times should I drain and refill to get all the old stuff out? Any problems if I don't get it all out? Anyone know of any history of problems when doing this? | ||
| Don Fairchild (Don_fairchild)
Registered Member Username: Don_fairchild Post Number: 27 Registered: 3-2007 Posted From: 66.17.9.74 Rating: N/A |
brandon; I went back to the service manual but mine does not have the trouble shooting section. You say it moves good in first but wont shift so the stator is working, The next is the gov. and you say they checked it, the next is the modulator, if it is good drop the pan and see what is in it. If it is full of black then the trans needs to come out. If there is just a little juk in it then drop the valve body and clean it and pull the two pipe plugs under the gov. pull the gov. and blow out the passages also there may be a small screen in one of the passages, clean it and put it back in. If you pull the valve body there will be some small ball bearings in a couple of spots.Don't lose them. You can look at the valve body gskt, to see where they go.use a small amount of petroleum jelly to hold them in place when you reinstall the valve body. I may be able to sent you some pic's if needed. Hope this helps Don | ||
| Brandon Merritt (Brando4905)
Registered Member Username: Brando4905 Post Number: 12 Registered: 3-2009 Posted From: 173.69.74.220 Rating: N/A |
Don, Thanks for all the good info. Definately helps! What do you think about the syn. fluid? The Culprit? Brandon | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1645 Registered: 12-2000 Posted From: 76.71.101.140  Rating: N/A |
I vote no, the synthetic is not the culprit. Busnuts on here have switched to synthetic in the V730, only good reports. Your transmission stopped shifting for a real reason, and you need to be told in specific terms what that reason is, by way of proper diagnosis by the people you are PAYING to look at it. The shop checked everything, and then you report they hadn't checked the pressures yet? Hadn't heard of the O ring coming out? And they are busy... Not a good combination. You best be careful. happy coaching! buswarrior | ||
| Don Fairchild (Don_fairchild)
Registered Member Username: Don_fairchild Post Number: 30 Registered: 3-2007 Posted From: 66.17.9.74 Rating: N/A |
Brandon; I don't think the syn. fluid is the problem Do you have any more news from the shop doing the work. Thanks Don | ||
| Brandon Merritt (Brando4905)
Registered Member Username: Brando4905 Post Number: 13 Registered: 3-2009 Posted From: 173.69.74.220 Rating: N/A |
Hey Don, The shop has a "good" used trans., they're taking the old one out now. Thanks, Brandon |