| Author | Message | ||
| Rusty Thompson (Rusty)
Rating: N/A |
has anyone installed a 2 speed differential in a 4104, I've been thinking about it lately, since it would be nice to have 2 rear gear ratios, one for climbing hills and one for going down the highway. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
The Consensus seems to be that it's a bad idea to install a 2 speed rear end in any large vehicle. Yes there are a few out there but the big deal is that 2 speed rear ends often "miss" shifts, and the only way to get back in gear is to stop entirely, fiddle with it until it gets back in gear, and start again. I had one in a 24' stake truck and I hated it for just that reason...and that truck weighed no-where near as much as your 4104... Though it's rare, the problem comes if your rear end happens to miss a split when going down a grade. Then you're suddenly in neutral and that could prove extremely uncomfortable under various circumstances. Just something to think about. Better would be a tranny with more speeds and an overdrive, lots less likely to "loose it" when coming down those long 6% ars-clenchers.... | ||
| jimmci9 #2 Rating: N/A |
lots of heavy haul trucks have 2 speed rears....and they regularly haul our companys' mud pump packages that weigh over 100k...my service truck at the caterpillar dealer where i worked was a gmc 2 1/2 ton... 5 speed main, 2 speed rear...called a working 4th and 5th... loved it...it weighed in at just under 26k... | ||
| Donald Lee Schwanke (Dontx)
Rating: N/A |
I think it might be a moot point, to the best of my knowledge, there never was a two speed angle drive rear end. Anybody ever hear of one? | ||
| Earl-8-Ky Rating: N/A |
I used to have a couple of trucks with 2 speed axles. They worked just fine. They were single rear axle trucks. I don't believe you could get both axles on a tandem to shift at the same time. | ||
| dougtheboneifiedbusnut
Rating: N/A |
Boy, am I getting an education here. In over twenty years of heavy trucking I have never heard of a 2 speed rear end refered to as a working 4th and 5th. Nor have I ever seen a "heavy" truck with a two speed rear end. Jimmi, what the bleep are you talking about! You say you drove a 2 1/2 ton truck that weight in at just under 26k . Gary, you are by far the electrical Guru and I am aleays amazed at how astute you are with regard to things electrical, but,geeeese you do not know of what you speek when you speek of two speed rear ends! Earl and Don are right on. | ||
| Tim Hoskinson (Tdh37514151)
Rating: N/A |
I believe the idea that the 4104 had a two speed rear axle came from the fact that a overdrive two speed clutch assymbly was available as a option. I have never seen in print nor have I even herd of a two speed v drive rear end for a 4104. The two speed clutch was hydraulic activated second clutch disc that had a set of planetary gears built into the disc. The unit was called a hydroshift unit. I have the supplement in my 4104 manual covering this unit. No where in any book I have on 4104 is there any mention of a two speed rear axle. I have seen two 4104 buses sold on e bay that had the hydroshift unit. | ||
| Bill K Rating: N/A |
I had several dump trucks with 2spd rear ends, these where 33000 lb GVW and they worked very well. one was a elect shift and the other air. The air was less trouble. and the only trouble with the elect if some water got in around the gasket of the elect. unite. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Well Doug, I might have my head up my you-know-where, but I had firsthand experience with the 2 speed rear end on my (ex, long ago sold) truck, and though the rear end was in perfect shape, it was a pain. Missing splits and having to stop happened a lot, and it wasn't the fault of the driver...it was how the things work. I'm sure a lot of guys will swear by 2 speed rear ends but I'm a guy who will generally swear at them. I only had the joy of finding myself inadvertantly in neutral whilst coming down a grade once in that truck, and I NEVER want to have that experience again. No sir. Thus, I stand by what I said... and if you still believe I'm way off base, I'm willing to accept that too, as long as you don't ever ask me to drive another 2 speed rear end down a grade!!  Oh... and the reason I said "The Consensus seems to be that it's a bad idea to install a 2 speed rear end in any large vehicle" is that I asked almost this very same question to a lot of truck suppliers and I think even on BNO maybe 5 years ago when I was just starting my Crown. I was in exactly the same situation, trying to figure out how to optimize my drive train. The answer from everyone I talked to (..."don't do it"....) and the reasons why are reflected in my comments in my first post above, and were confirmed from personal experience. (Message edited by boogiethecat on April 24, 2006) | ||
| Phil Dumpster2 Rating: N/A |
You can avoid brown trousers syndrome flying down a hill with a two speed axle grinding along in "Neutral" if you DON'T SHIFT THE BLOODY THING ON A DOWNGRADE IN THE FIRST PLACE! Just some friendly advice from a professional driver who has lots of experience negotiating favorably with gravity. | ||
| Jim (Skyslayer)
Rating: N/A |
I have actually seen one on a guys 4104 in San Jose, CA some of you my know him his name is Bill I don’t know his last name. I would love to have two speed axle. The ExtremeFamily 1964 4106-2802 | ||
| niles steckbauer (Niles500)
Rating: N/A |
Never have seen one on a bus - but back in the late 70's when I drove for GESCO - they had a straight truck (think it was a jimmy) with a 2 speed rear, air operated on a tandem rear (but single screw) and I can't remeber the GVW but it was well in excess of 26K lbs. - FWIW | ||
| 4104bgs Rating: N/A |
I have seed more than 10 of them, THEY DO EXIST Someone in Western GM Coach (FMCA Chapter)years ago made up a unit that install in front of the Pumpkin that was 3nd & 4th gear from some other trans. He made up the casting that married the two together. Cable or air shifted. There are some 4104's still running around with them.George Thornhill had one. | ||
| Jarlaxle Rating: N/A |
I have driven plenty of miles with 2-speed axles--in fact, I trained for my CDL in a Ford L8000 (GVWR 28,500) with a 5+2. I have NEVER, not once, under no circumstances had one miss a shift. I've had an electric-shift axle (70's GMC) NOT shift when I hit the switch due to a corroded connection, but NEVER had one hang up. I gotta agree with Phil about NOT shifting the axle on a downgrade. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I really do not see any difference in missing a shift with a two speed axle than missing a shift with a standard four speed in a 4104. I have done that a couple of times and never had any trouble bringing the bus to a stop beside the road to re-engage the tranny in the gear I wanted. I find it hard to believe that anyone would have their brakes so hot that they could not come to a stop. I have also had the same thing happen with a three speed differential. Can not for the life of me remember what it is called. Had a five speed tranny then a three speed differential. Missed a gear coming into Vegas one time and that is a big steep grade. Richard Richard | ||
| Doug G Rating: N/A |
I drove a 4104 with a Hydroshift in the early 70's across country. There was a small push-pull knob on the shifter. Even after the clutches were rebuilt it would occassionally pop out of gear. | ||
| truthhunter@shaw.ca Rating: N/A |
Dumpster & Slazy are both right, when melded into on rule of thumb . And of course the caveat is never drive on big or unknown down grade if you have for some reason gotten your brakes "smoken" as drive lines do break on rare occasion without much warning (think broken axle), on very rare occasion. $ My second conversion bus was a International school on propane, 7 ton with a 2 speed axle for the mountain $ It worked fine, but I did miss a few times. Keep them brakes cool in the first place. | ||
| Len Silva (Lsilva)
Rating: N/A |
I had some info on the two speeds which I just posted on the gmc-busnuts egroup: http://autos.groups.yahoo.com/group/gmc-busnuts/message/48177 It seems like it would be a major project, certainly beyond my capabilities. Good luck, Len Silva | ||
| Dallas Farnworth (Dal300)
Rating: N/A |
If any one wants the 4104 Supplement on the 4104 with the Hydrashift, email me. One thing I heard, but don't know for certain, was that the planetary gears and clutches came directly from the VS2. I don't have a VS2 manual, so, I can't tell one way or the other. Dallas PD4103-1085 GHTrucking at msn.com |