Problem 4104 Motor or Trans

4104SoFl · June 06, 2017, 05:16:25 PM

1956 4104 671 cranks right up, the dip stick comes out a little. When I try to move it, I have to rev it up all the way and slip the clutch to get it to move.
This does not seem right to me. If I do not slip the clutch until I get it moving it will stall it out. Too me it would seem that I should just about let the clutch out and go. 671 is suppose to have about 700 or more pounds of torque.
Can some one please tell me how there 671 pulls away?

Do I have a problem?

Geoff · June 06, 2017, 05:36:47 PM

Your problem sounds like the reverse is geared high so it is not torque, but ratio. How fast is your bus in reverse with the clutch fully engaged with the rpms low? I'm sure some 4104 owners can chine in hear on this one.

--Geoff

chessie4905 · June 06, 2017, 05:40:28 PM

Are the brakes dragging? Also emergency brake, if it still has one. You don't have dd-3's? You are in first gear? If those aren't issues and you aren't belching black smoke...(emergency shutoff accidently engaged) you don't have a 3:55 rear end and are on level ground and fuel filters aren't plugged, then you could have a governor issue. On level ground, my 4104 would ease out by just slowly releasing the clutch. Would need some throttle at a traffic light.

4104SoFl · June 06, 2017, 05:48:30 PM

Ok I'm going to anwser Geoff 1st. I hope you are not tring to make fun of me. I thought there was only two gear ratios that would fit in the 4104. The one I have is the one that lets you run about 66 or, 67 on the highway. I do not know the gear ratio. Reverse is the same as forward. Have to rev it to get it moving.

4104SoFl · June 06, 2017, 05:56:30 PM

I still have the emergency brake lever, I do not think it works thou. Do not know if they are DD-3's. I am in first gear. No black smoke. Filter are not plugged.
Govenor issue HMMMMM. No tack on dash of course. Motor seems to rev up perrty good. Thank you for the questions and ideas. I'm gutting it now. Have given up chasing 1956 wiring. Going to rewire the whole bus. I would just like to figure this out before I dump a lot of money in it and have a motor that is failing.

Boomer · June 06, 2017, 09:06:37 PM

The most common ratio was the 4.12. Also offered was 3.89 and 3.55. Sounds like from your speeds you have 4.12. If your clutch is in good shape you should be able to pull away in first with no problem on flat ground if your brakes are released all the way. In reverse, the trans ratio is close to the second gear ratio so backing up will require more expertise and clutch slipping and a little chatter is normal.

chessie4905 · June 07, 2017, 03:00:56 AM

If have the 4:12 gears which is most common, top speed will be 68 or 69 if tires are 12:00x 22.5 or 11:00x22's less with any other size.The 3:55 gears will run about 77 or 78 mph at the expense of less startability in 1st or Reverse. This vehicle weighs 9 to 10 tons empty so it won't start out like a car or truck. Especially so since it only has a 4 speed and they sacrificed startability somewhat. No granny gear, but transmission is very durable and they experience few failures. BTW, reverse is about the equivalent or a little less of second gear, so it requires finesse backing up; more so if you are on a grade. Don't even bother trying to back up a steep grade or on soft ground. Quick way to burn the clutch. Majority of owners drove this model with great success. Very reliable model. If you are on soft ground, starting out will require some feathering of clutch and throttle to get moving,more of both in reverse.

4104SoFl · June 07, 2017, 04:15:34 AM

So, I guess I will jack up the back of the bus ( not today) and rotate the drive shaft and see how many times it turns to one revolution of the tire. I had a mechanic help start it up when I first bought it. He has also been out once since then. Both times he told me the motor sounded real good. Certainly he was getting max rpm without moving the bus. Sure sounded like the 2150 rpm range. Instance max rpm, no real smoke. Lets say it does have the 3.55 ratio, would this cause the take off problem. I've only drove it once. When I moved from the the third owner to my house. I have moved it around the yard.

dtcerrato · June 07, 2017, 04:18:34 AM

Orv
Going back to the start of your post, you said it cranks right up. what did you mean when you say "the dip stick comes out a little"? just curious.
We're here in Florida North of you near Ocala. We too have a 4104 we love driving for almost 40 years now. From the context - it doesn't sound like engine issue. How long has the bus been sitting since you last moved it? The "drag" you are explaining sounds like brakes are lock up or the parking brake could be dragging. Without getting under the bus the parking brake can be easily checked. If sitting for awhile rust could be an issue (on brakes or parking brake). When you say "If I do not slip the clutch until I get it moving it will stall out" - I need to ask when you do have it moving do you still feel the drag? or does it feel free wheeling. No one here is trying to make fun of anything - we'd really like to help a fellow bus nut especially a fellow 4104 bus nut!

zubzub · June 07, 2017, 04:21:41 AM

I'm not sure if a 671 will start and rev with the engine shutdown flap tripped. I know mine won't shut down with the flap tripped and still produces some power. Maybe give that a look see. While we are at it, did some critters make a nest in the air intake and now the suction has pulled into a tight spot ?

dtcerrato · June 07, 2017, 04:22:59 AM

Even if you had a 355 rear end, unless you are in soft sand or spongy grass - on the flat with hard surface it should roll away easier than your saying... Have you always felt this "drag" you are experiencing on all the moves you mentioned?

chessie4905 · June 07, 2017, 04:32:59 AM

On hard level ground in neutral, two can push coach to check dragging brakes.

4104SoFl · June 07, 2017, 04:42:22 AM

Thank you dtcerrato: The dip stick has no resistance in the hole. If it was upside down it would fall out. Moves out just a little. I would be more concerend about this as a motor problem of some sort if it wern't for the it being so loose. Thought I would throw that out as a fact thou. Bus has been sitting about 6 month since last move, but has been like this taking off since I bought it. I do not think the buses brake are sticking. When moving it, once I get it going it will roll perty easy. I do not belive it is a sticking brake. "Free Wheeling". I just wanted other opions. I will make sure of gearing because the third owner and man who converted it said he had changed the gear ratio.
zubzub: I will check that out "Critters" is a definite posiblity.
dtcerrato: Soft grass to start with but good dirt / shell sock road and yes I have had this drag issue from the begining.
chessie4905: This weekend I'll get one of my buddy's to come over and we will try and push it. For some reason this idea apeals to me. It is sitting in the driveway now. Asphalted.
Thanks everyone, I going to finsh the tear down and get the lights working. That should not cost much. Then on to the problem. Time is not an issue for me right now. Money is.

Nel · June 07, 2017, 07:31:08 AM

My 4104 takes off easily with no throttle input at all off idle on most flat ground, sounds like you are on your way to a seriously fried clutch using it that way. Like most have said here something is either dragging badly or the engine is not producing torque with the governor properly at low rpm.

4104SoFl · June 07, 2017, 07:37:50 AM

I always felt that it should just take off. 700 or so pounds of torque and only 20,000 total weight. I'm going to have to check it out. Clutch is good now and I do not want to hurt it. Thanks for your input also. All input is welcome.