Okay, I loaded up and was ready for my trip to Syracuse New York today . going through my pre travel check and lo and behold she wouldn't go into reverse. I said no big deal who needs reverse! And then thought about it and said let me find out why.
Check the switch and the wires replace the switch because it was cheap. Continuity in the wires and 24 volts coming in to the switch. So check the relay picture below. It's been replaced 2 years ago. Along with the solenoid. Picture below.
So how do you tell if the relay is bad? I can't even see the cylinoid on top of the transmission without Burying my head in grease covered hoses from the pull out compartment in the rear of the coach on the floor. So another question is, exactly what do I do to manually put her in reverse?? The search features here do not come up with the same threads every time. I'm really confused as to what mechanics take place when it's operating correctly at the transmission. In other words descriptions on what I and a helper if required need to do to manually put it in reverse. Thanks gentlemen any help is certainly appreciated.
#2
#3
Testing the solenoid relay is pretty easy. You should have 24v supply to your switch. When you throw the switch, it should have 24v at the other wire. if it does not, the switch is bad. It sends current to the solenoid relay, so you should find 24v at the input terminal. If it does not, there is a short between the relay and the switch.That magnetically connects a full time 24v source to the wire going to the transmission solenoid. You generally can hear it snapping. If that does not happen, the solenoid relay is bad. If the transmission is getting 24v, then it could be the transmission solenoid or there could be stuck or some other mechanical failure.
From my limited experience with the Spicer, although I dislike them I considered them pretty hardy, so would expect the problem to be before the transmission.
I ran for a few days with Betty getting out, opening the back door and pulling on a rope to mimic the operation of the solenoid.
Inside the solenoid is a contact which provides full current during the pull-in and then reduces the current once it is in hold-in to prevent the windings from burning out. If the contact is bad, the windings won't be energised.
You need to remove the cap off the end of the solenoid where the wire is attached. Remove power wire and nut securing the stud to the cap. Remove two small screws holding cap to solenoid. You will see a pair of contacts. These disconnect the pull in coil in the solenoid and leave holding coil powered as long as the switch up front is energized. You need to power the solenoid and observe that the points open when solenoid makes it's stroke. The gap specs aren't listed in the GM book, just that the points open. Adjust for point gap when energized by adjusting linkage that connects plunger to trans shift rod. The linkage may appear to be sloppy loose when done, but as long as the points open, say .035 to.060. If the points look burned, you can dress them with a point file or Emory paper. I had a problem with our 4104 several years ago. It wouldn't go into reverse when warmed up. Problem appeared to be solenoid weakness. I got a new one from Luke and same problem. I finally dug out the manual and adjusted per the instructions. Linkage was too tight. Adjusted and never had any more problems.
I actually created the problem, when a few months before, I replaced the wire end on solenoid because it looked crappy. While I was back there I tightened the "excess slop" in the solenoid linkage. The result was that the solenoid couldn't initially move enough to move the reverse lever and open the points. Once adjusted, it worked fine and linkage was sloppy just like before I fooled with it.Lesson and the cost of a so!enoid learned.
I get tired of trying to repair or find a replacement for those solenoids.I am just changing those over to air.I use a Bendix TW control valve a Norgren or a cylinder from a old road ranger transmission make a bracket which is simple and easy.Run a 1/4 supply line to the TW valve on the dash a 1/4 inch line to the cylinder on the transmission and you are done.No more electrical problems after that
I like Clifford's idea, although really the solenoid is pretty simple, can be quickly cleaned and adjusted, the relay controlling it is auto electrics 101 and should not challenge anyone either. The problem is the solenoid is a little wimpy so anything amiss causes problems, air would be nice and very easy to do with a cylinder, I might use a lectric valve to control it, but I'm not scared of simple circuits (just black boxes).
I can see why Clifford likes air setup, but on GM, they are right there easy to check or maintain.
Thanks gentlemen, to clarify I have replace the switch. The relay indicated in the very last picture the real shining one new 2 years ago and sealed with no access to the interior. The other two pictures are attempts at viewing the new two-year-old solenoid which I can barley see from hatch inside the coach much less get to it from under it. Without jacking it up or having a bay under it. And then I'm not sure how they got to it putting the new one in. To clarify my question earlier. The other two pictures show the new shiny solenoid attached to a swivel lever that looks like a open-end wrench attached to a shaft. When operating correctly does the solenoid push the lever into reverse or pull the lever into reverse? I'd like to attempt to put it into reverse manually as indicated in one of the other threads with one person operating the switch up front and one pushing or pulling reverse. Just looking some Direction so I know I can get it in reverse when needed. Until I resolve electrical. Thanks again gentlemen have a great Memorial Day and if you served in any capacity thank you and God bless!
In the case of my 05 Eagle, I would pull towards the outside of the body to engage. Your arrangement might be different, but you have a 50% chance of being correct if you pull it. Have a way to push it back or you won't be going forward.
Going back isn't an issue as there should be a strong spring returning the lever to the "off" position. Pull the rope, driver slips it into second position (reverse) and then the rope is let go. Go to neutral and the box resets to normal forward mode
Lou, in the last photo, it looks like that solenoid might be hitting on a hose. Is it possible the hose is interfering with the free movement of the shift solenoid?
Regardless, if your helper just pulls the lever in the direction that the solenoid would push it when enngaged, while you operate the switch, it should shift and allow you to get it into reverse.
What happens is this: Dash switch on, shift lever in neutral. Solenoid's pull in coil is energized, about 30 amps, and the slug inside the solenoid is pulled in, thus pulling in on the end of the lever. As soon as the slug is pulled all the way in it operates a points mechanism that shuts off the pull-in coil and the hold-in coil (6 amps I recall) stays active as long as the switch is left on. The lever will pull the shaft in the transmission top housing out. When the shaft is pulled out it disengages the 1/2 shift rod from the shifter from the 1/2 shift fork, and engages the reverse shift fork. This also locks the 1/2 shift fork in neutral so it can't move (the 1/2 shift hub on the main shaft of the tranny is also reverse gear). Now, when you shift into the second gear position on the shift lever you are actually operating the reverse shift fork inside the transmission, which moves the reverse idler gear into engagement with reverse on the layshaft and reverse on the main shaft. As soon as you are in reverse you release the switch, which turns the solenoid off. Nothing happens at that point because the gearbox is locked into reverse. As soon as you are finished with reverse, you shift into neutral. That releases the shaft in the transmission top housing, and a spring forces the shaft back into the 1/2 position and puts the slug in the solenoid back into it's normal ready position.
So if you want to shift into reverse without the solenoid you need to move that shaft out from the housing into the reverse position, then shift into reverse, which locks the shaft out while you stay in reverse gear. You can do it from the top with a screw driver or obviously you can hook a rope onto it and pull it from the passenger side engine bay. You only need to pull it out while actually doing the shifting, your helper doesn't need to hold it out once you are in reverse gear.
Sometimes the internal switch (just exactly like a set of ignition points to look at) fails and the pull-in coil doesn't get switched off as soon as the solenoid has fully operated. That burns out the solenoid if current is left on too long. For this reason it is always good practice to hold the dash switch on for the minimum period of time to allow you to shift into reverse gear - just in case it is stuck in high-current pull-in mode.
Hope this explains how shifting into reverse works.
Edit: in the picture, the large straight cut gear in the foreground is the 1/2 sliding hub and mainshaft reverse gear. The little straight cut gear to the left is the reverse idler gear. It is slid into engagement with the big gear when you shift into reverse. The grinding you hear when you shift into reverse is the teeth on those gears getting eaten up. For interest's sake, that gearbox is sitting with first gear engaged, the hub has slid down and is engaged with first gear, which is the bottom helical cut gear. Second gear is the one directly above the sliding hub, and you can see the coarse splines on the main shaft that it slides on. The gears are engaged to the main shaft when the sliding hub slides up those splines (which are about 1/4" square splines, and slides over the tiny little matching teeth on second gear. Those tiny little 1/4" square teeth are what grind when you shift into second (or any other) gear. This is why you try really hard not to grind gears - those tiny little teeth get eaten up.
Brian
All of these details makes me glad I have a Allison now. When I had trouble with my Spicer there was no spring return action at all and I had to push and pull.
Here is my experience with the reverse solenoid. I backed up from our camping site and the reverse switch stayed in the on position while driving home. The switch is a momentary switch that goes back to the off position after using it. Once it stayed on it screwed the switch and also burnt the wire to the back (starter solenoid). I replaced the reverse switch with a heavy duty one. I also replaced the wire from front of bus to the back to a circuit breaker and also the starter solenoid that sends power to the reverse solenoid. After all this I still had no power to the reverse solenoid. I replaced the wire that runs from the starter solenoid to the reverse solenoid. I have reverse now and also I have used WD-40 to loosen up the mechanical parts on top of the transmission where the reverse solenoid fork. My whole system is 12 volt but should have same electrical components as your 24 volt system.
So here's a quick update. I talked to Lou earlier today. We've confirmed that the switch and relay are working properly. So the problem is something in the solenoid However, due to it's position, he is physically unable to get to it or even see it from within the bus. When we departed, he was off to find a jack and some considerable lumber for blocking with the intent of getting the bus safely up so he could get under it and investigate the solenoid setup. I've given him the 3 most likely problems to check: loss of ground, not getting 24v, and binding of the linkage. I actually think it's likely to be the linkage, from looking at the photos, but the other two should be quick and easy tests with his volt meter so might as well rule them out early.
BTW, Lou, if you don't get anywhere with the 3 checks above, you should consider removing the 24v wire from the solenoid and testing for continuity across the 24v terminal to ground (i.e. check the coil for continuity). Call me if you need further explanation on this.
craig
Thanks again Craig !!! I did get a stubby bottle jack and blocked her up but was so dang tard from laying on my belly or chest with little leverage I had to give up for the day. Then researched ramps on here and figured with my single axle I could reduce the length and overall weight of the plywood by half but my calculations are still approx 140 lbs per 16" W x 4`L with 4" step/run and 13 layers @ 9.75 high would still weigh approx 140lbs . Dang that`s heavy and still need more height? for all but slithering around under. Would solve my jack issue and be safer?
Gota drive 800 miles tomorrow eve for work so may Build`m next weekend ? Cant take me more than a few hours I`m thinking.
Whats the best pneumatic stubby bottle jack out there to buy? Trying to work smart not hard :-)
And what other light weight material can a set of ramps be made from??
I just wana get under her safely and check the solenoid out as Craig described .
I was able to get a 1/8 gauge braided wire threaded in the solenoid but unable to move the Armature into reverse. Guessing because the cylinoid on top of the transmission bound. Either burned up or too tight as Craig describe.
air over jack from HF plus whatever little thing will lift it enough to get the air over in. easier a few lifts going between 2 jacks to lift a bus enough to work under. you need to put blocking under jacks as you go, and
Never get under the bus that is sitting only on jacks
, block/crib the body as you go. 2 air overs would be ideal, but I use one bottle jack and one air over, and lots of jacking.....but that is for fancy work, if you just want to get under there, run up ramps, with blocking between axle and body should get the height you need.....oh yeah, without reverse you might have trouble getting up on ramps....
Hello again folks. Update. I trouble shot the switch and teethe relay and all is fine no shorts brakes 24 volts as need.
She is parked on decent level ground a slight incline but soft Earth. I have a hand crank 20 ton bottle jack which is mounds of work !
I could only climb under her so far and got a bit aggravated and disappointed to say the least.
I have located a Truck Service mechanic that has his own shop locally where I'm from.
And plan on driving it over there tomorrow to get it up on ramps and or Jax and maybe cool the tires off to see if I can get to the solenoid. My question is this .....
I backed her in where she sits now since I brought it back from Florida, the solenoid working fine But from a different direction. Not sure I can pull her out and make the corner coming out of the driveway, can I put her in neutral and have my friend and his farm tractor pull her backwards while I readjust the steering ( without damaging anything) and then make the corner to continue forward get to its destination.???
. I'm guessing 8 or 10 feet at best.
I'm going to try this at 7 a.m. tomorrow Eastern Time.
You will make it out okay, it will be easy compared to what you have already been through.
Quote from: lou432 on June 10, 2016, 05:40:48 PM
My question is this .....
I backed her in where she sits now since I brought it back from Florida, the solenoid working fine But from a different direction. Not sure I can pull her out and make the corner coming out of the driveway, can I put her in neutral and have my friend and his farm tractor pull her backwards while I readjust the steering ( without damaging anything) and then make the corner to continue forward get to its destination.???
. I'm guessing 8 or 10 feet at best.
Short answer is yes. Caveat is make sure you attache the tow chain or rope to a proper place. The engine cradle is NOT the proper place. Nor is the bumper. You can probably use the tow hitch, if so equipped. Just be gentle. Otherwise, get it around the axle. If it's level ground and not too soft, he should have no problem pulling you in neutral.
You might find that if you move it forward a bit, the reverse solenoid will magically start working!
Thanks Craig ! I was thinking the same thing and hoping it would do it but it did not but I did not have to use the tractor as we were on a slight decline when I pulled out so I was able to Coast backwards readjust my steering and get out of the driveway. I didn't have the time or the equipment and to be honest with you the gumption to further my fixing it.
So I drove it to a local truck mechanic he can at least get to the solenoid. He does not have a pit. But he has ramps and Jack's. If I need another solenoid where should I start? Purchasing one that is.
Another question is can I just loosen the slack up in that solenoid and pull on the Rope that I have attached to it now? Or better yet is there any other way to avoid putting another solenoid on? I know I'm looking for the easy way out but I'm a bit disappointed and perplexed at its location and the difficulty of adjusting it or even getting to it much less replacing it. So another words ,HELP !! :-)
He is going to grease my slack adjusters while he has the tires off so there's a positive note. Thanks and Have a great day guys!
If it's bad and needs to be replaced, I would suggest contacting Luke or C&J Bus Repair in Bloomington, MN. (cjbusrepair.com) Either will have it or know where you can get it.
Someone else commented earlier in this thread that they have replaced that electric solenoid with an air solenoid. That may be something you want to consider if you have more
problems with this one.
I'm hoping it's just the connections binding that are causing your problems.
Have him adjust the brakes while he's greasing the slack adjusters.
Well, selinoid is getting juice and probably needs replacement . But the truck mechanic figured out that by swinging the wire/rope I tied to the armature around from passage side pull ti driver side pull I can get into reverse..yaayyyyyy!!! Heading to Syracuse in a few minutes to her summer home on Sylvan lake just north of the city.
266 miles to go and I'll keep u all in the loop .
Thanks again for all your ideas and reply Really does refresh the soul !!!
Easy as can be, you are on your way! What could possibly go wrong?
Louis,
I sent you a message on your Facebook regarding a possible replacement source.
craig
Similar problem here, my 68 gmc Suburban Fishbowl 4503A with a 4 speed spicer is doing a very similar dance. Bought it, guy delivered 50 miles in the august heat, reversed it in parked it, bam sister wants me to move it and the reverse solenoid does not work..
Does it need to engage in first then go thru neutral to 2nd?? I keep ending up in 2nd (from neutral, brother in law helping at back). My spicer does not want to shift into first even when it is not running, however the guy who delivered it ground the living crpoa out of it :|
Seems to like to bind and not shift while engine is running after grinding it a little myself arg!
On the mci it sounds like you might pull lever opposite? On the GMC you open up the tranny door on the pass side and the thing is staring mocking.
How far should the rod pull out an inch? Seems to sit a half inch out as is. If I pry a large screwdriver in the crack where the rod is while in neutral going to hurt anything? Thanks for any help, George
found a couple posts that might help, posing them here..
ZubZub
Need to be gentle with an old bus. Open up the rear hatches and have a look see. Make sure you chock the wheels and have one person up front gently moving the shifter, another in the engine bay, gently working out what is stuck. Hopefully something simple....
Not too gentle, a little reefing may be required, oh and grease, everywhere you see zerk.
My 4104 does this when I forget to completely push the clutch all the way in or get sloppy with my shifts.
The solution is to go the rear where the two vertical levers attach to the two rods going into the trans. You will note that they are not lined up together. One will be appx straight up and is in neutral. The other one is hung up.
Have someone hold in the clutch all the way in while you pull the other lever upright and even with the other. This takes a little effort but if an old guy like me can do it anyone can!!
I've probably done this 20 times in 72,000 mi but it solves the problem.
This is all assuming nothing is broken or loose. These levers could be loose on the rods and your linkage is probably badly worn, most are."
FloridaCliff L&S,
Cliff..Baker4106My 4106 has a stud installed on top of the transmission with a shifting fork kept on the stud with a castlelated nut. When the nut loosened or stripped the threads it allowed the shifting fork to come off the shifting lever in the transmission leaving it stuck in gear. By loosing the nut, I reinstalled the shifting fork on the shifting lever,retightened the nut and shifted it out of gear. I then replaced the nut with a new one and it has worked good for 3 years.
I had the same issue baker4106 had om my 4905.
You may have to take it off the stud to get it free or just loosen it up.
Once free you can see how it can get stuck and how it should be just free enough to move, but not too loose.
Mine was moving around like a ball joint, but once fixed shifted smooth.
I have also learned to square the shift pattern with the Spicer, not meander over like in a syncro transmission.
bevans6:
There is/should be a grease nipple to lube the throw-out bearing - is that still there? Anyway, I would start by disconnecting the linkage at the top under the floor cut-out to separate the whole pedal linkage from the clutch meccanno set on the gearbox, , and start playing with it to see what is stuck. Fiddle about and look for what is binding. Mine had seized heim joints on the aforementioned air assist cylinder, fwiw.
Brian
gus:
As Len said, on GMCs there are numerous clevises and pins from the pedal to the clutch, a few worn pins and wallowed out clevises multiply into a great big slack in the system. I spent many hours on my 4104 replacing all these things. I found the cross shaft under the driver also lose in its mount.
However, the biggest problem was the bellcrank at the firewall where the clutch rods connect and make a 90* turn to the clutch rods. The arm holes in the bellcrank were completely worn through the bushings into the arm castings.
Even after all this my clutch still dragged. I just learned to live with shutting down the engine to get to first gear, after that I was careful to shift down into first in traffic just before coming to a stop, it takes very little movement to make it easy. This is hard on the clutch leg though if one stops for a long traffic light! When that happens I just shut down to shift. A nuisance but doable.
You should also check shift tower behind engine on firewall. There is a stack of short levers that transfer motion of rods that go through central tunnel to shift lever bell cranks at back to connect to shifter up front. Those short levers connect to rods that go to the transmission. Inside each lever on the stack usually has a needle bearing. The vertical shaft they pivot on has a facing down grease fitting that transfers grease to the levers. On our former 4104, some of those levers were worn so much, bearing was completely gone. Also the pin and holes where the rods connected were egg shaped. At that time you could still buy the vertical shaft and new levers. Wow, what a difference. Movement at shift lever was cut in half and now precise. We greased that shaft regularily at every service, including the pivots up front above front axle. There are an incredible number of grease fittings on these coaches. Copy the location picture in the service manual and laminate it for use at every service.
Thx Chessie I'll check those! Trying to get my buddy to help me tonight, coach is about half an hour away at my sisters..
On my fishbowl 4 speed the tunnel spot you speak of is accessible from the rear top access, where I stare down at the other 3 cyl's.
I started about making sure the measurements were correct for the clutch from the front, working to the back but wow are those spaces fun to work in! Where the 'firewall' is the clutch shaft steps up and goes just back to the right of the drivers arm. Anyone know what / how interior part to start disassembling to perform the necessary measurements and adjustments..Looks like it is drivers side of the galley way, but how does this come up? Hate to tear it up if I do not have to. Thanks, George
The front pivot levers on mine are vertical mounted on a horizontal shaft. The rear ones are horizontal mounted on a vertical shaft.
So thru the top engine access I found the clevis point's that should be aligned, Although I was looking for needle bearings ;) on the transmission (I thought thats where the control tower was, geez its the big stick shifting thing up front dummy!) Yes the Clevis points are a little sloppy..Are these things common at fastner stores? Guessing they probably are.. Well going to try and get them aligned today..
Some materials I dug up.. on fishbowls the clevis center should be 1.78in away from firewall and here is the part I am confused about.."center of clevis pin's must be in line with each other and centered on a line thru the two shaft assemblies..Adjust then tighten lock nuts..(dont think I saw any lock nuts)
So first of all it describes aligning the center of clevis pins which would make me think that the Pass side control rods should be aligned vertically so you could drop a nail thru them... Then I picture no.. they are talking about the horizontal line 1.78in from the bulkhead on a horizontal pane intersecting each side of the bus at 90 degree angles.. Additionally where one of the rods meet the transmission there is very little clearance to the firewall infact It looks like sometimes it does contact the firewall lightly. Hmm..
So..I am trying to 'reset' my transmission to it's default state, I had just started the process of extracting pins when I noticed my 1962 manual differs from what I am looking at in my 1968..In 1962 the process was to measure the distance to the firewall 1.78" from the center of the Clovis pin hole..As described in Section 'transmission control and maintenance'..
I looks like they changed things up a little as in my 68 s6m one of the rods the 62' manual denotes for gear shifting is used for the clutch(.. So dunno if this throws the 1.78" everything out the window?
Probably just go 1.78" on the both and see where it get's me even though the rod holes and positions changed in the 6 years. Included a video link of the clearance in neutral, need about .7 inches.
https://www.youtube.com/watch?v=QCFa1Zjv_dw&feature=youtu.be (https://www.youtube.com/watch?v=QCFa1Zjv_dw&feature=youtu.be)