My name is Mark, I bought a 1980 GMC H8H649 about a month ago, The bus came with a manual transmission from GM someone installed a VS2-8 automatic transmission which is fine but , you have to shut the bus off to change gears from forward to revease. After looking high and low on the net noone seems to have a wiring diagram for the H8H649. I have one for a 1978 4905a bus but it dont show one with the VS2-8 trans as a option. can anyone help me wire this up , what parts will I need and where can I get them?? Thanks alot for reading Mark
Quote from: tanman496 on September 05, 2012, 09:32:15 PM
My name is Mark, I bought a 1980 GMC H8H649 about a month ago, The bus came with a manual transmission from GM someone installed a VS2-8 automatic transmission which is fine but , you have to shut the bus off to change gears from forward to revease. After looking high and low on the net noone seems to have a wiring diagram for the H8H649. I have one for a 1978 4905a bus but it dont show one with the VS2-8 trans as a option. can anyone help me wire this up , what parts will I need and where can I get them?? Thanks alot for reading Mark
Why do you have to turn it off to switch from f-r? Is it because it grinds and does not want to go into gear? Has someone bypassed the neutral safety and you have to start it in gear?
http://brandon314.wordpress.com/2011/08/12/vh-vs-series-service-manual/ (http://brandon314.wordpress.com/2011/08/12/vh-vs-series-service-manual/)
Yes it does grind when you try to put into gear. And yes it will start in any gear so I guess the neutral safety switch is disconnected
That is a common problem. The neutral safety switch is a great work around. I have a similar trans the VH9, you have the better looking sister trans to mine. I start in gear to avoid the grinding. I can switch gears from F to R once the fluid is warmed up. But I have to do it fast. Out and into the other gear really fast. I've never heard of a fix for the problem other than the workaround which you already have. Loren joplin said it had something to do with a hanging clutch pack that was a GM change up that had that negative result. I don't know about that, I was also told that it might be a few other things too. Just don't grind the gears, if it happens stop it right away.
If you find a fix, let me know.... I've asked, otherwise it's not to bad to live with it. I avoid parking where I have to put it into reverse, and mostly just leave it in F
I had a VS2-8 in my 5301 and had the same trouble. I always started it in neutral until I had good air pressure. Then I shut down-put in Forward, and restarted. I could switch from F to R and back again if I did it quickly once the fluid was warmed up.
It was never a problem for me, and some days I wish I had the Automatic in my 4905, especially when trying to back in a campsite and not slip the wet clutch!
Steve Toomey
PAbusnut
well someone installed this transmission but never installed all the parts that go with it , like a shift switch and all the wiring that has to be hooked up so you have backup lights. Its a real pain to have to shut it off to change gears when your trying to turn the bus around.
My bus a 61 GMC didn't come with back up lights or any wiring for them. I added them myself.
tanman, you might want to look up Bill Gerrie over at BNO.
He knows an awful lot about these transmissions and might have a few ideas for you.
happy coaching!
buswarrior
Thanks Bus warrior I never heard of BNO Who are they?? do you have a number for them?
Quote from: tanman496 on September 18, 2012, 02:35:48 PM
Thanks Bus warrior I never heard of BNO Who are they?? do you have a number for them?
BNO is "the other board"
Sent from my PantechP9070 using Tapatalk 2
BNO, Bus Nuts On Line a forum like this almost the same they have some great GM people there
good luck
www.busnut.com (http://www.busnut.com)
Click on the "BNO BBS" link in the LH column.
FWIW & HTH. . .
;)