| Author | Message | ||
| dave tiehen (209.137.231.116) Rating: N/A |
anybody have this problem w/their's. i have already had 4 speed out and have eliminated any problems that would be clutch related. i have thouroghly inspected the engine cradle and bulkhead and related frame work and all is sound, no cracks anywhere. any help would be appreciated. dave | ||
| RJ Long (Rjlong) (67.181.236.27)
Rating: N/A |
Dave - Slop in the driveshaft splines, slop in the driveshaft u-joints, and slop in the "dogbone" (radius rod) bushings can all contribute to rear end hop. So can oil on the clutch disc, too. Did it hop if you eased it away from a stop without using any throttle at all until the clutch was fully engaged?? (This is called a "dead throttle start, btw.) HTH, RJ PD4106-2784 Fresno CA | ||
| TWO DOGS (63.185.80.99) Rating: N/A |
motor mounts.....u-joint....shock absorbers.. what kind of a hop...just rolling in first gear ?? any noise...need better description of symtoms | ||
| TWO DOGS (63.185.80.99) Rating: N/A |
that dead throttle start R.J. is talking about is the correct way to take off ,no pressure on the footfeed until clutch is out...hard to get used to,but,you need to do it THAT WAY | ||
| mclough (63.235.52.188)
Rating: N/A |
what about starting out on a hill, how do u start out ? | ||
| TWO DOGS (63.185.81.133) Rating: N/A |
you can give it a little....but just enough to keep the engine running...no power till the clutch is out...going to be hard to get used to...believe me ....you won't be able to pay all the repair bills if you don't learn this... | ||
| RJ Long (Rjlong) (67.181.236.27)
Rating: N/A |
Regarding the Dead Throttle Start: Please understand that this is NOT simply "dumping the clutch" in one swift move!!! A DTS is done (on a bus) by gently working your way thru the clutch take-up point to get the coach rolling. Once the clutch is fully engaged, then you add throttle to accelerate. 18-wheeler jockeys may do it differently, but that's the way it's taught in the bus industry. (I even taught my two kids this method when they learned to drive stick shifts.  ) On a grade, you use the parking brake to hold the coach, bring the clutch out until you begin to feel the take-up point, add just a tiny bit of throttle, and come the rest of the way thru the take-up point while releasing the parking brake. Takes a little coordination and practice. Just don't slip the clutch!! Too easy to burn 'em out in a bus w/ a four or five speed. Different story if it's got a RoadRanger, 'cause then you've got stump-pullers to work with. . . HTH, RJ PD4106-2784 Fresno CA | ||
| FAST FRED (4.245.212.174) Rating: N/A |
The gov built into the engine will pick up the load as you slowly release the clutch. The Extra throttle is needed only if the hill is SO steep that at idle the coach would stall. DTS ,technique works for me, Thanks RJ! FAST FRED | ||
| John Rigby (65.112.227.94)
Rating: N/A |
I agree as I have burnt two clutches out in 18 years. One was done trying to get the old 4104 out off a soft area. Dont DO IT GET IT PULLED TO HARD GROUND. Im a believer. John | ||
| dave (209.137.231.95) Rating: N/A |
rj, thankyou and the rest for timely response. ok , i am using the dead throttle to start out with. driveline and u-joints are in good shape. don't know about condition of radius rod bushings. i looked at them but didn't see any visible wear, seemed to be tight. is some clutch hop normal for these buses being the transmission gearing is so high? i talked to luke at us coach, he said could be a combination of smaller things like flooring bolts etc. being the design of gmc as "mono(whatever)"type construction. also has anybody converted to automatic and cured this problem | ||
| TWO DOGS (65.177.145.62) Rating: N/A |
everybody has their own beliefs...autos never cure a problem...just make more problems...stay standard.. | ||
| Kyle Brandt (Kyle4501) (65.23.106.193)
Rating: N/A |
Hi 2D, Since I an a newbie, I need all the help I can get, what are the problems with an automatic? I am the one who just bought the scenicruiser off of ebay and want to convert to auto. My 8V71 runs stong on the highway but does not seem to handle a DTS. It idles at 500 rpm. Is this the correct setting? | ||
| TWO DOGS (65.177.145.62) Rating: N/A |
probably spell this wrong...."SUBCONCIOUSLY"...you just said the problem was in the clutch area | ||
| TWO DOGS (65.177.145.62) Rating: N/A |
man...I'd give 100.00 to drive a senic cruiser...yeah that sounds about correct for a diesel...top r.p.m. shouldn't be above 2000...it's all a learning process...dead throttle start,double clutch on shifts...if I can learn it...you can learn it...just have to make up your mind...does kinda sound like clutch tho...get a friend that drives big trucks to try it...if he has problems..then I'd say it was the clutch/pressure plate.. | ||
| TWO DOGS (65.177.145.62) Rating: N/A |
are you sure you are pressing hard on the brake pedal AFTER you release the park brake... | ||
| Jim-Bob (12.46.52.74) Rating: N/A |
If the engine wants to (and does) stall when starting out dead throttle on reasonably flat ground, you probably need to adjust the governor & racks. Mine did that. It acted like it had no power. After a properly done tune up, when you put load on the engine at idle, the governor gives it fuel very quickly. It should bark as you let the clutch out some & push it back in. If it just loses rpms unless you give it throttle, it needs adjusting. The engine should hunt for a minute or two when started cold at 75-80 degrees before smoothing out. (Longer if it's colder.) If it doesn't hunt at all, the buffer screw is too tight. Some folks set the idle with it but that's wrong. Get the DD book I read the "tune up" section. Also I had hopping for some time. It went away after I repaired a loose rear radius rod bracket & for some reason, a cracked & sagging engine cradle. (each made a difference) | ||
| John Rigby (24.174.238.253)
Rating: N/A |
Jim-Bob, More info please, as my 04 and several of my bus nut friends all have problems with hopping. Which radius rod and how did you detect it?? Where on the engine cradle was the problem and how did you find it?? It seems that these 4104,s have the hopping problem in the high reverse gear and in first gear, its common to many. On reading your many posts, I see you have taken time and lots of hard work solving a lot of the challanges we all face with these wonderful GM PD4104 AND 4104,S. Thank You. John | ||
| Jim-Bob (205.188.116.135) Rating: N/A |
John, I noticed orange rust marks around the two 3/4"? bolts that fasten the triangle plates to the chassis. The one I found was the right rear upper one. My cradle had a trailer hitch attached to it. The previous owner had been pulling a 20' Pace trailer when a pickup t-boned the trailer. The side force ripped the rivets out of the two center aluminum channels that angle outward towards the front of the cradle. I fabricated some new steel channels & had to use a lot of force to pull the rear of the cradle forward enough to ge the holes to line up. Now, to be fair, it still hops a little sometimes. But I still have a LOT of play in the differential. But 85% of the hop is gone. Another thing to check is that the clutch pressure plate arms are correctly adjusted. If they are not, you will get hop. | ||
| John Rigby (24.174.238.253)
Rating: N/A |
Jim-Bob, The last time I redid the clutch, I took it to the cluch rebuiler himself, asking him if he needed the book to set the fingers. He said he new the settings. While installing I ckecked the the finger setings, they were not even close. Just shows you not to trust, but to ALWAYS check. I also agree with you about this adjustment, and think it is a weak point on the power train that as there is only one cluch plate it easily comes out of adjustment. I also hear U-bolts, radius rod bushings engine mounts, But that clutch plate??? John |