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TOPICS => THE BOARD => Topic started by: Jack Ashore on December 02, 2015, 02:01:48 PM
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I'm sorta broke down in Charleston, SC with an Allison VS2-8 tranny that is acting up, i.e., occasionally failing to downshift from direct into turbo when I approach a stop, and then stalling. The Allison specialists here, W.W. Williams, say the transmission fluid is burnt, and someone needs to get inside to see the damage. They don't want to do it. They will, with great reluctance, give it a go but are clearly uncomfortable and they think I should have them remove it and send the tranny to someone that knows this stuff. Of course, they don't know who that would be. Any recommendations? I am half tempted to have them drain and fill it with fresh tranny fluid and take my chances getting back to Florida where I at least have relatives and friends I can stay with if need be.
Thanks,
Jack
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Try General Diesel:
http://www.allisontransmission.com/sales-service-locator (http://www.allisontransmission.com/sales-service-locator)
See if they can help you. It's odd that the Allison site has Williams listed as a service facility. But we used General Diesel a long while ago...they were great.
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Hi Jack & Folks:
The burnt fluid doesn't sound good. You might start with the governor, as if it hangs up, the result can be the problem you are having.
If you think it might help, give us a call.
LUKE at US COACH
1-888-262-2434
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Thanks for the General Diesel recommendation, I spoke to Aaron and he expressed no hesitation at getting into it. Says he worked on 60's era stuff before. I am confident I can nurse the bus the 4.9 miles from WW Williams to his General Diesel.
Luke, thanks for the offer, and I will pass on the bit about the governor to the General Diesel people. I have had occasion to connect "younger" mechanics with Ted out at Coach Maintenance Company for phone tech assists on this old bus, is that something you or your people would do as well? Or are you mainly parts? I know your company provided the guts to our Voltage Regulator when when we got it fixed at Interstate Power Systems in Omaha last month, so thanks for that.
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A quick pressure gauge test would show if the problem is with the governor or the valves that do the switching. Fortunately the converter lockup valve is the easiest to access (right at the passenger rear corner of the trans up top).
These transmissions do NOT like running low or too full. I run wet-clutch tractor hydraulic oil in mine and it's been pretty happy (other than a leaker).
I have the manual posted online https://brandon314.wordpress.com/2011/08/12/vh-vs-series-service-manual/
I would not open up the transmission without first checking the condition of the oil (maybe drop the pan and see if any solids in there). Since you're not getting slipping, I'd suspect valves or the governor sticking due to contamination or messed up pressures. Good luck!
Video of governor pressure across speed range (bus was blocked so wheels could spin)
https://www.youtube.com/watch?v=JaeyZekXpG4
My transmission has weak main pressure...so some of the other videos are not good reference material.
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Brandon, Thanks! I will pass this along to General Diesel as well. Great to have such specific information to provide. I tend to agree that it is something sticking in the governor or valve body given that everything else works so well. The transmission, aside from this new problem, works a lot better overall since the clutch replacement, particularly the transition between direct and overdrive. The one bit of oddness is the transition from turbo to direct going up in speed: I think the mechanic set the thing up to wait too long to transfer, up near 35 MPH instead of 28 or so. Not sure if this has anything to do with the problem coming down the gear train.
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The one bit of oddness is the transition from turbo to direct going up in speed: I think the mechanic set the thing up to wait too long to transfer, up near 35 MPH instead of 28 or so. Not sure if this has anything to do with the problem coming down the gear train.
Mine moves in/out of lockup around 27-29MPH (though my rear differential is ~55MPH during lockup at 2250RPM). That is easily adjusted with shims on the particular valve. A 'high' setting would usually make it drop out sooner as you slow down. There is some overlap there to make sure it doesn't flap back-forth wildly trying to decide (hysteresis)....but if it is sticking.
My splitter overdrive changeover is really crappy because of my low main pressure. I've changed the main pump, futzed with the pressure relief valves, and pressure hasn't moved an inch. I need to do some more elaborate testing to see if I can get it up closer to 95-100psi. I have a manual override to select direct drive (for hill climbs, decent, etc.) so I usually hold that until I hit 50MPH+ then do the changeover to O/D while letting off the accelerator. I set the clutch up pretty tight but not tight enough for that crap pressure apparently. :-)
Cheers!
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Brandon, You're speaking beyond my mechanical knowledge level, but I appreciate the info. Dang it why didn't I know about you when I spent a month in Portland this summer!?
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Brandon, You're speaking beyond my mechanical knowledge level, but I appreciate the info. Dang it why didn't I know about you when I spent a month in Portland this summer!?
Download that manual and start reading. It's written surprisingly well. Thanks to Bill Gerrie for loaning it to me so I could scan into digital! Cheers!
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You are most welcome Jack. My father used to say it's the unwritten bus nut code that if you can help a fellow nut, you do ;D
Luke: Where are you all located? I'm going to put your number in my bus contact list, if that's OK.
Brandon: Great blog!
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Brandon: Great blog!
www.theghostbus.org is where the bus project/driving blog lives. It's pretty quiet lately as I haven't had time to update with the work I've done. But it has the basics :-)
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Brandon, Regarding fluid for the VS2, I had on old bus mechanic (Ted from Coach Maintenance Company) tell me that even though the manuals call for Dexron II, the industry learned that 40 wt was better for some reason. I see you are using wet clutch tractor hydraulic oil, so I guess you don't like the modern Dexron option either. In the absence of tractor hydraulic oil, would you recommend 40 wt or something else?
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Brandon, Regarding fluid for the VS2, I had on old bus mechanic (Ted from Coach Maintenance Company) tell me that even though the manuals call for Dexron II, the industry learned that 40 wt was better for some reason. I see you are using wet clutch tractor hydraulic oil, so I guess you don't like the modern Dexron option either. In the absence of tractor hydraulic oil, would you recommend 40 wt or something else?
My bus had Dexron in it before...I changed it out for the tractor wet clutch transmission oil (which is cheaper and available at almost every farm store/Napa/etc). I can get a part number tonight if you like. I've heard folks run all sorts of stuff. I chose this fluid because my father (a heavy equipment mechanic) recommended it. They run it in dozers/etc. which have remarkably similar style transmissions and far more difficult working loads/environments.
I was low on fluid and we were out in some little touristy town in WA doing a vintage 4x4 meetup so I hit up the local NAPA and even they had 5-gal pails of it and it was very cheap. I dropped the pan recently to re-gasket and didn't find any alarming levels of nasty in the oil. It stays the same golden brown color and AFAIK exceeds the vintage Allison fluid requirements.
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Great thanks. If you have the time the part number would be helpful.
As an update, this morning I drove the bus over to General Diesel, staying in low gear the whole time to avoid a stalling scenario. The assigned mechanic and his supervisor do not claim experience on this model, but seem game to figure it out. I have forwarded them all of your comments on this blog, which he read immediately, and I just sent him Brandon's ghostbus.org blog, so hopefully he gets the time to look at all the Allison transmission posts. Right now they are dropping the pan to inspect. They have already found some tiny metal flakes, a bad sign, but I am hoping the damage is limited. They felt there was no point in going at the governor until they had at least checked for any obvious damage from the pan.
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Post a picture if you can of what was found in the pan.
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I would also like to see what they found in the pan. Do you know what color the fluid was? or How did it smell? Strange questions that can be revealing.
I'm glad you made it to General Diesel.
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Cr@p. Things don't look good. Found chunks of what they think is clutch in the pan. Pieces about 1/8" or more even. If clutch needs replacement, they don't think they are qualified to do the rebuild. Manager is proposing they research a remanufactured transmission. He think it would probably be about as cost effective as the labor to rebuild the existing one. Of course, he hasn't yet even looked into how hard that would be to find. I'll post a pic as soon as I figure out this site's procedure for it.
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(http://i477.photobucket.com/albums/rr132/Osteomata/IMG_20151203_145939_zps8sbwxvhd.jpg) (http://s477.photobucket.com/user/Osteomata/media/IMG_20151203_145939_zps8sbwxvhd.jpg.html)
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That is definitely bad looking. Much larger chunks that expected.
There is a VS2-8 for sale here nearby in Portland for $700 with an 8v71 attached. I've seen it on Craigslist and considered buying it but the owner never got back to me on what the bevel gear ratio was (there are two options...the spare in my driveway is the wrong one for my bus!)
http://portland.craigslist.org/mlt/hvo/5334496811.html
You can call up Pioneer Transmission in IL (http://pioneertransserv.com/)
They know their stuff. Old school shop...used to keep fleets of the VS alive and kicking.
Luke would also be an excellent resource to talk to.
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I'm so sorry. That does look bad all around.
This is just MHO, but I would put a new (rebuilt) tranny in it.
I think a lot of mechanics might be hesitant to get into the existing unit because they have no idea what they'll find and quoting you a price can be tricky. Then there is the whole warranty issue, because they don't really know your bus, how it's operated etc...
This might not make you feel any better (I hope it does), but when all is said and done, if everyone is safe... it's just a bad day.
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Brandon, daddysgirl, all,
I spoke to Luke, who patiently listened to my tale of whoa and said he needs to put on his thinking cap for a bit to come up with some options for me regarding parts.
I spoke to Gary at Pioneer Transmission (who has a high opinion of Brandon's skills/knowledge level by the way) and he walked me, and then the young mechanic assigned to this case, through the process of checking the governor and valve body for blockage and port alignment to address the very specific symptoms I am facing. He approached it from the standpoint of getting me on the road long enough to get back to home base in Florida where we can deal with this problem as something other than an emergency. This is exactly the approach I wanted to take. He seems to think that if it is shifting fine going up the gear train and we onl have a problem with the Direct to Turbine downshift, then we stand a very good chance of making it home without incident. I hope I am not distorting his views based upon false hope.
Meanwhile, the service manager here is making inquiries for sending the transmission out for rebuild, I don't think he has had any luck finding a re-man.
Right now I am warming it up so we can verify the right tranny fluid level, after which we will park nearby and reassess in the morning. I have to give it to General Diesel: they have not given up, and have been very flexible with us about being in the bus and where we can spend the night right off of their property.
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I don't know where you are located but Ted Keating will probably have 1 on the shelf try him 1-800-997-4858 is the last number I have, he is Yanceyville NC he shipped me one about 3 years ago
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Reminder, checking the level on these transmissions is not obvious. If memory serves...main dipstick on the filler (between engine and transmission, big guy) is pulled within seconds of shutting down engine idling, in gear (or neutral?). Check level on dipstick.
The pan refills quickly from the torque converter upon shutdown so have to be quick.
I've never used the small dipstick on the side but I suppose you could use that one to check while running? I don't remember seeing it in the manual.
Overfull is just as bad if not worse than under (will froth, overheat, and cause pressure issues)...been there done that!
I might suggest getting 150psi gauge + hose that you can get inside the bus for checking pressures while underway (unless the shop can get the bus up off the ground so the tires can safely spin).
Gary is good people. Haven't seen him and the crew in 15+ years. He and my father are friends as well from his days doing GSE support in Chicago for Evergreen Aviation. Keep us updated!
Let me know if any confusion about plumbing/etc. I have a stock VS2-8 at home to use for reference.
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Thanks Brandon. Right now we are sitting thirty feet outside the General Diesel property line in a paved turnout, "stealth camping," with the intention of backing into one of their bays when they open tomorrow morning. We have our faithful Honda 2000 generator powering our fridge, lights, and a heater. Tomorrow General Diesel will go through the process Gary provided to clear the governor and valve body of any debris. I strongly suspect we will then make a run for Florida where we can re-assess our situation. Fingers crossed.
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I don't know enough about the transmission that you have in your bus to help fix it but someone that is in our Southeast Bus Nuts might. If you call Kirby Karlsson he may be able to help. I know he had problems out west and had a spare at home shipped to him to replace the bad one. Kirby may know where you can get a used that would be a lot less than a rebuild. Kirby's cell 305-788-4104. Look at his number and guess what kind of bus he has.
Jack
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You have coach net??, shouldn't leave home without it, just saying
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It's your money but me I would toss the piece of trash, find a flywheel and a V730 and be done with it, then we all do it different but the V730 is a far superior transmission that works good in a 4106 JMO
The problem with a VS2 they don't have enough HP or torque rating for the 8v71 what are they rated for ? something less that 200 hp and 600 ft lbs of torque.
I know some models are rated at 250 HP and 750 ft lbs I believe the VS8 was not sure about if any where rated higher or not ,that is the highest ratings I ever saw
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IF you are going to work on it I have the
DD "SA 1239D" which is the factory book for VH and VS transmissions.
It has sections on description and operation, preventive maint and the overhaul and assembly procedure , all 15 fold outs are intact.
1971 edition in good to use condition.
$50 postpaid if you need it. 860-346- 5008
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Here's what I run in my VS2-8
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Hydraulic-Fluid-All-Purpose-Tractor-5-GAL-Warren-Unilube-Inc-/_/R-FHQ85475_0509237194
I think even cheaper last time I bought it...but expect price around there somewhere. Regularly available at other farm stores too.