Hello, We have a 91 Pete that has a intermittent issue with shifting. Sometimes when splitting the gears on the high side it will go into some sort of neutral freewheel. The only way to get it to re-engage is to stop the truck using the brakes and re-start. This happens primarily on the splitter but has also done it a few times on the high/low selector as well. Looking for ideas?
First Place to start is the air system and valves. The air is feed into the pressure regulator at right rear top of transmission, there are two range cyliners on the rear section. The lower one on left is the splitter, the one on the top right behind the regulator is the range cylinder. The valve on the left side near the top/ middle is the slave valve. Sounds like the air system is dry, remove the air fed line from frame to pressure regulator at rear of transmission, get a bottle of air tool oil and squirt a good amount down the air fed line once it stops flowing air. Reconnect, build air and operate the low range and splitter back and forth several times. If it was dry it was also/probably shifting slow. With the air tool oil it should speed up the shifts. Normally this symptom happens when the slave valve is dry. Moisture in those air lines is not good, water plays hell with that air system. Has the air dryer been serviced recently?
I don't like to just throw parts at stuff, but if it looks pretty old I will replace the filter/regulator unit if it looks like it has seen much moisture. So far I've been right on the last 3 cases. The air tool oil first.
It has a very old looking self contained Bendix Air dryer. Maybe I should look into this, as we did have some issues this winter with ice in the lines not allowing the box to raise or lower. I'll squirt some oil in the lines and see about getting a new element or whatever air dryer takes. Thanks for ideas!!!
I may be well off-base here but I always thought that the idea was to keep water and oil out of the air system downstream of the air compressor but maybe I'm wrong............
Correct, but over time the air system on these transmissions will collect crap and the o-rings start to drag instead of sliding. Plus where I was headed with the air dryer without asking the direct question told me a possibility of air line antifreeze could have been used to clear the ice in the air lines. I hate airline antifreeze {alcohol} it dries out any air valves it makes it's way to.
This is the dryer. Anyone familiar with servicing it or just by new? Hoping to lube up and try the system tomorrow
You remove the whole unit, split the nuts and bolts around the perimeter. Swap out the desiccant and put her back together. Now turn it upside down and take those 3 little screws out and replace the purge valve/heater assembly. Reinstall and your done. Or in the interest of time, swap with a reman unit.
I'd be interested to hear what's the recommended interval between dessicant cartridge replacements for an on-highway truck..? Our off-highway equipment we replace every 1000 hours which equates to every couple of months give or take.
Interested to hear what the fix is. Strip & clean the valve, S&C plus some sort of lubricant, etc, etc..?
On highway is recommended annually. Truck shop will back me on this, they're usually forgotten till something happens.
The exhaust ports aren't substantial enough to purge the dirt and crud. You would have to disassemble clean/polish and reseal. It's a PITA but the only 'right' way to do the job. I myself have sprayed blaster or wd-40 in a slave or 20 over the years. Plus, like truck shop mentioned, the air brake alcohol is terrible. It turns the aluminum to chalk, corrodes relay valves from the inside. You wanna really lose hair quick. Try to troubleshoot an air problem on a gradall that someone pours alcohol into regularly. Holy smokes, I just wanna burn it to the ground and start over.
Bendix o-ring lube in the cylinders and on the o-rings.
Excellent thanks, I think I’ll opt for a new one. This one is pretty crusty trying to get off. Ive found some more info on the on my neutral problem. It seems the splitter sometimes does not dump into the low side. And stays high, so if I shift into the low side (1-4) where there is no split available it makes terrible noise and stays in a neutral. So which actuator is the splitter and which line should I squirt some lube?
In the bottom photo the feed line with the white fuller parts tag sticking up is the one to put air oil in. But before you do that-in the second photo remove the rubber hose to the splitter valve and see if anything drains out of it. That line has a dip in it which is a collection point for oil and water. There are only three ranges, low, direct and over drive. The Splitter will only work in direct and overdrive. Photo of the control knob please!
Excellent, I will take care of this today. definitly going to check that rubber hose with the dip in it. It sounds like the splitter is unable to dump properly. The range selector from high to low has a very audible clunk when toggling up and down. The splitter on side, not so much. I am not by the truck but this is the type of shifter it has
In that splitter valve is a shuttle valve that can get covered with crud. It is opposite the 5/32 line and has a port in the end of it, it takes a 7/8 socket to remove the cover plug and carefully use needle nose pliers to grab the stem without bending it pull it straight out and clean the bore it slides in and clean plus lube the shuttle and reinstall.
Had occasion to just replace the shuttle on the Dir/OD spool, the pin insert was the culprit with debris damage over time that would not seal for shifts.
I have two new ones in my tool box. And I agree Dave those shuttles can be problematic I'm just trying to help him through it without throwing any parts at it. At least until they have an idea whats wrong.
This may have been mentioned but I didn't see it. Have you washed out the sintered brass filter under the 1 1/2" plug on the trans. air regulator yet?
Have gotten away with cleaning the shuttle at times A little silicone grease on those orings is good too Used to save the tubes of that when supplied with trans valve kits, they still put those in the packages?
Not yet, because the high/low works. when the splitter starts working then the owner can pickup a new regulator and shuttle for splitter. You brought that up before in a thread on HTF three years ago.
Hate to think it, could also have loose/broken/otherwise damaged pins in the clutch/synchro assembly, hanging it up when shifted, am hoping NOT.
I cleaned as much as I could last night, I removed that brass plug opposite of 5/32 line, but was unable to remove the unit inside. I could grip in with needle nose but in wouldnt budge. I did notice the brass plug had a machined hole in it and air was escaping through it very slightly. I lubed everything else up that was mentioned and the splitter/od has a very positive clunk now when operating. Going to test it out today. If it works I will be able to replace it! thanks for the helps
For whatever it’s worth, here is the tag
This is the little device you did not get out, really need to get that out and inspect/lube if not replace. p/n 19974 https://holsttruck.com/parts/details?part=80900815
Actually, his first post said the problem occurred most often with the splitter, but with the high/low also. I try to mention it any time air shifting problems come up, because washing that filter is a quick, cheap way to rule out one cause of inadequate air, and just something the old junk I see needs periodically.
The splitter seemed to work OK the Hi/low did malfunction on me tho. Where is this filter before I jump to bigger problems
Under the top cap of the multiline regulator in the last photo. file:///C:/Users/ddm50/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/2074-Air%20filter%20regulator%20assembly%20(1).pdf
There is also a sliding lockout dowel that prevents the air shift Hi/LO and LO/Hi behind the valve on the side of the case, if it gets gummy and the spring fails to retract it the system will do the same. By the outward appearance of your gear box I would have a look at that as well. Page 10 and in the manual as to location/passenger side right below top cover. file:///C:/Users/ddm50/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/super-parts-book%20(1).pdf
It's all yours guy's. I found his problem, and I seriously doubt anyone on here even comes close to the amount of Eaton's I have rebuilt through the years.
I tip my hat to a master I cannot compete to and admit I am not as learned.
Dave the truth be known I'm faking it, I'm only a #3 grease monkey!
Now that I seriously doubt!! Good Humility though. I do need humbling on occasion.
Well there are days if I was a #3 things would be better as less responsibility for me. And I'm not trying to humble anyone and I fu^k up a enough **** anyway all by myself.
Hello DMiller, there is no photo attached. Is this a file or manual I can find somewhere? Thanks
Ah ha! This is where it’s at! I can hardly wait to try this! I have found that alcohol tends to clean out the air lines and send it all downstream... I’ll take a picture of evidence
Unfortunately its as clean as a whistle
Not a told anyone so, but that is why I wasn't worried about the screen.
Sooo... Cleaned that screen out with brake clean and air. I had one of my guys running it for about 3 hrs today without any problems! he said it seemed a little slow clunking from high to low but did not do the "stuck in neutral, have to stop to get it in gear" problem. We will be running it a full day tomorrow. Thanks for your guys' help so far! You ever make it up to Alaska I'll buy you a beer or dinner!
If it's still slow shifting from High to Low without any grinding noises, I would replace the entire regulator filter unit. The regulator is not adjustable and gets weaker with age. Alcohol does bad stuff to the diaphragm and valve seat, not to mention hardening from old age anyways.
Not trying to start any arguments, but I've seen this work over and over on older vocational type stuff. When you posted that pic of how clean it was, I started to tell you to wash it anyway. And I second replacing the regulator if this helps but not fixes it, but I never have. All the stuff about cleaning and oiling those components is very true, but none of it works if you don't get enough air, and washing the filter is quick and cheap.
So where that filter is concerned it would appear that there's obviously clean and "clean" .........
We ran it for 8 hrs on Friday and it only had a problem once! Still a little slow actuating, I would like to replace this whole unit as mentioned. Does any one have a part number or its "official" name for oredering? Its a RTOF 14613 Trans. Thanks!
We had a similar issue with my buddy's Mack truck this spring . It would not shift at all . I first removed the small 5/32 " pilot line " line from the cylinder cover & had the driver shift the switch . We have good air flow ! Also have to be carful not to overtighten the ferrule nut as that can restrict air flow . We then removed the 4 bolt piston cover and took it to the workbench vice . Have to be carful as air cylinder body my try to come out as well . We loosened the 4 bolts a little and popped the cover loose from the body with a light tap from a chisel . Removed the bolts & cover " oil will drain out the holes so have a small container ready & be fast " . And Installed the bolts back in the cylinder body . Now at the workbench removed the plug and valve assembly . " dirty & grimy " Cleaned it all up , blew out all ports with compressed air and reinstalled lubing it all up with engine oil . Fixed the shifting problem .
I've always called it the "Filter/Regulator unit" most parts guys had no problem with that. I think they are all the same... But I have been wrong about stuff before.
Just a update, we replaced the regulator and splitter valve. Completely solved the going into neutral while trying to split problem. Every once in awhile going from 4th to 5th (low to high) it will go into freespool. But if you shift the splitter up it will catch and then you can go up or down... Very weird and intermittent but at least its manageable now! Thanks again for the help
What kind of oil is in it and what condition? Had a 10 speed that used to do that and then the oil got changed and it was better. Like the synchro was taking longer to shift than it took to move the lever.