HI All, I have 1985 S1900 international with a 5 sp and 2 sp rear . My helper supposedly knew how to work the 2 speed BUT I swear I heard an awful lot of Clicking as the 2 speed struggled to shift (I was not in the truck at the time but rather following behind with the windows down). I'm not sure what he did or didn't do to cause all that (I later suggested to him just to run the truck in low range 1 to 5 on the tranny and only use the high / low in 5th on the highway (we were running light and I figure the less he used the 2 speed the less potential problems there would be). Anyways, after much practice and reading he claimed he had the hang of it so I sent him on a long distance run with the truck (100 miles out 1 way mostly highway until the pick up then back). We he go to the destination the truck cut off unexpectedly but he managed to get a jump to get him going again....I told him NOT to shut the truck off until he got back (it has a manual cut off so no problem running without juice in the batteries).... Anyways, he told me the 2 speed was not working and he was stuck in low range...This made for a 45 MPH run for 100 miles on the interstate. We got the truck back to the shop and I stuck a battery charger on it.....Batteries pretty much dead. Turns out the alternator was bad so it is being replaced..... I figured the 2 speed rear was not shifting due to low voltage so after charging the batteries for a day, I took it for a test drive and to my disappointment, it would not shift into high range ....UGH. When I pulled up on the switch and clutched there was no shifting into high range.....It just went into "neutral" on the rear end (i.e. I could be in gear on the trans but if I pushed on the accelerator it's as though the rear is in "neutral"..... When I pushed the switch back to low range, the truck runs fine.....except for being in low range only in the rear end... So what happened ? .....Did all the grinding mess something up (I am assuming it did). How to fix this situation (is it a "normal" thing that happens when inexperienced people use the 2 speed?).... Admittedly, early on in my 2 speed learning, if I ever got to having the rear make strange noises or not want to shift quite right I always had the presence of mind to push the clutch in to help the shift (I usually use the clutch even when I don't have to when operating the 2 speed rear to make it "easier" on the motor etc...).....My helpers usually seem to apply more power to "fix" things....Ugh.... Thanks in advance for any and all help. Andrew
Older two speeds were electric with points. No please excuse me as the older older ones were vacuum shift. The newer old ones were up dated to printed circuit boards. Low voltage and or age could cause ether to be a problem. Hope it is in the shift unit. Check it out and or jug a magnet down in the diff and see what you find.
That happens to experienced drivers to, nature of a two speed rear end as far as I know. Find out what's wrong before you blame the driver.
I've seen the electrics get water on that circuit board and basically turn in windshield wiper motors, just bouncing between positions
On my 2spd there is a spring in the mix: motor moves shift arm moves and loads the spring, then, when you back off throttle and take load off gears, it shifts. Perhaps it isn’t making full travel to engage hi range? Darryl
I've seen the motors seize up from corrosion. Maybe it was more the calender's fault than the new driver. Fun story, I worked on an old grain truck once, maybe a GM? Anyway, it was a tandem twin screw but both axles had an electrically shifted 2 speed. Well, at some point one axle shifted and the other didn't. That dramatically shortened the life of the power divider. Apparently, someone actually made a rig that was designed to work that way. Both in low, both in high, or one in high and one in low. It gave a half ratio between the two ranges. I've never actually seen one, but I have heard stories.
Yep, 3 speed Eaton tandems. The ones I have seen were air shifted with a thumb switch on the shift knob. Just use the throttle like shifting a 2 speed.
I heard that the power divider taking up all that difference wore too fast in the 3 speeds. Tandem trucks could also have just 2 speeds, they would shift hi/lo at the same time because they underwent the same conditions, but around here 2 speeds were always a medium single drive thing.
Yes, I think power divider wear was the main reason the 3 spd. tandems were discontinued. I've driven a few 2 spd tandems and never done a shift on the fly except an up shift at slower speeds. Going into low was always at rest with a bit of clutch jiggle to make sure they shifted down fully. Those were air shift also, that was just the way the owner wanted them run.
We converted a great deal of the old three speed set ups to two, shifted BOTH third members together, worked fine until didn't. PD did catch hell on the three speeds. What I am hearing is the spool has probably munched. These are pretty simple sliding dog clutch spool to either a sun gear lock or a side gear release. Shear the splines and will do this grind them over and they do this. First things ALWAYS first, check the wiring (power to) the high and low sides at the shift box, get the shifter mechanism off and try it by hand rolling the driveline(WHEELS BLOCKED), then check the two speed shift motor assembly and internals for destruction, finally drain some oil check for chunks.
Just an update, since I needed the truck to work, I bought am entire new motor assembly... Turns out the old one broke at the rod that pushes on the lever (?) to change gears....I'll buy the necessary pieces and keep it a spare when the next helper screws this one up ;-O
Tell your helper to always shift the two speed in the higher gear, whether he is going up or down. When going from low to high, don't granny shift it. Tach it out in low, it will shift to high just fine. Going from high to low slow to near idle before switching to low, then gently feather the throttle to bring the engine rpm up to match road speed.
Seems like Associated Grocers had some of those in their cabovers. they are the only ones I have seen
Ford used to be really big on three speed Eaton rears mostly in the late 60's/70's on Gas engine tandems. Were quite a mess when got 'Lost' in a shift.
They were Fords cabovers! I don't remember what they had for power... Cummins, I think.
My buddy has a H ford with a V Cummins 2 speed tandams. Its the only H ford i have saw in person.