OK, mostly this is a plea for a parts source. I believe I have narrowed this down to the F-N-R switch, or possibly the wiring. I get a good solid engagement in F, but nothing in R, regardless of speed selection. Opening up the speed switch, as far as I could without removing the steering wheel to access the wiring to the stalk (stoopid design, imo), I see that parts of the contact system is a bit crispy, so I will need to replace that. Once, while doing the jiggle test, it did engage firmly in R, so I'm pretty convinced it is not a solenoid or clutch/hydraulic issue. The operators said it was fine up until suddenly today R quit altogether. I'd rather buy online than drive the 100 miles to the nearest dealer, so what I'm hoping for is that someone has access to a parts book. I found several online for JCB equipment, but only specified the OEM PN, which I do not have. The tag is pretty washed out, so I can't say which is the SN, but here are all the numbers on it. SLP53000VE0770458 844336C 449/061/3/00087 15479 1997 6000
Not sure on the exact part number for yours. But you can buy them cheap on ebay. Just search "jcb forward reverse" Maybe you can just see which looks like yours.
Maybe? https://www.johnconaty.com/701-52601-p/1946.htm https://www.amazon.com/Signal-Switch-Forward-Reverse-52601/dp/B07GFD11TD https://www.ebay.com/itm/701-52601-SWITCH-FWD-REV-SHUTTLE-TRANS-fits-JCB-/291813737252
Another https://www.ebay.com/itm/Forward-Re...074247&hash=item2d05b41f2b:g:9WwAAOSwQz1bEkjk
Well honestly they all look pretty much alike. I have not pulled mine yet to have a look at the connector, which is the most obvious difference in those you found. Some specify the model number machine they fit, and don't list the 530. One does, however, and shows the oem pn to be 701/52601. Do we agree that is the correct number?
Best guess without an actual parts book?
Just pop the steering cover off and look. Take a minute to do.
Maybe not the same issue, but I lost reverse on a Terex 4010 telehandler. It turned out to be a high resistance to ground from the selector. Why it only affected reverse, I don't know. A new wire to ground solved the issue.
I ordered one that specified several variants of the 530 series. It was a little higher than some, but the lower cost ones were shipping from China, and I'd rather not wait on it longer than needed. This lift is very handy for it's purpose. We run a firewood cutting/splitting operation with 2 saw/splitters. This lift is equipped with a claw, so it's better than a standard forked lift that the guys are forced to use until this one is fixed.
Well, with the best intentions I'm sure, the engineers decided not to split the cover on the column on this one. The screws that secure the cover to the column are not accessible without removing the steering wheel. One nut holds it on. I didn't have my puller on the truck, so I'll have to get that look next trip. Removing the nut didn't allow me to pull the wheel. A little rusty I suppose. Same for replacing the switch. Has to be scattered a bit.
I'll be double checking all the wiring once I have the covers off. I would think the same ground circuit would be in play for both F and R, but who can say. Grounds are funny things sometimes.
Best I could figure is that there was just enough current with the increase to activate the solenoid for forward travel. In reverse, with the additional load of the beeper & lights, there wasn't. But I'm no electrical guru.
That's a possibility, especially if the machine was old enough to have incandescent bulb rather than LED lighting, but the backup alarm likely would draw more. Good thought. On the JCB at least, and likely the Terex, the stalk switch only controls a relay, with the JCB relays mounted on the same board as all the fuses. I feel pretty good clicks with my finger on the F relay, but can't say for sure which is the R relay, since it doesn't work. I suppose I could swap the relays around, as I'm sure they are the same for shifting F/R. I didn't try that. Lost confidence in the stalk switch when discovering the crispy parts. Generally a bad sign on electrical parts.
The steering wheels aren't that tight on the shaft. Pull on the steering wheel and hit the shaft with a hammer may break it loose. Keep the nut on the shaft end to prevent thread damage from hammer.
Does this machine have a TCU?
Skata, this one is, but it's just rust and I soaked it down before I left yesterday. It will come off easy enough. Vetech, define TCU (Trans Control Unit?) If that's it, I haven't discovered it yet. Honestly, I didn't spend a lot of time with it. I just removed the internal snap ring on the stalk switch and had a look inside, punched the microswitches that the lever actuates, and tried briefly on the wheel. I have a habit of not working on my birthday, which was yesterday, but it sounded really urgent when the owner called, so I made a quick exception.
Correct! You can still have a TCU controller even with an electric shifter. There was a lot of older stuff back in the day that was electric shifted with and without a TCU. Do you know what make and model transmission you have? I’m working on a JCB 722 articulated truck right now with a TCU operated ZF.
I don't think the telehandler transmission has a tcu. At least the older ones for sure didn't. The forward /reverse lever just triggered solenoids on the transmission.
I wasn’t sure which system we are dealing with.
I don't believe this model does. Just above the trans, there is a valve bank, for lack of a better term, that has some solenoids on it. I'm not sure how (yet) how it all works to give the machine 4 speeds, automatic style, with only a pair of solenoids, but there easily could be additional wiring connections on the trans. It does automatically upshift when the stalk switch it set to a higher gear than 1. Naturally, I've no service manual for it. Figured it's a simple machine and hoped not to need it. I actually have a yard full of telehandlers of various makes that were brought in from auctions. We have 2 or 3 that we use regularly, but this is the only JCB. So I can't make any meaningful comparisons of their workings. Oh, and no, I don't know what trans is in it yet either. It was a fast service call.
Without the tcu it should be a pretty standard setup. 5 solenoids would be the most popular. There will be a forward solenoid and a reverse solenoid......then 3-4 other solenoids for your range speeds. It will take electrical power to a combination of specific solenoids to get the direction and the range selected by the shifter. If you can get the transmission make model and serial number of the transmission, I may be able to supply the solenoid diagram for you which will help in the troubleshooting.
I'll try to get that Monday. Would be nice to have that diagram. I'll probably have to give it a washdown just to locate the tag, if it's still on there. It's probably encoded in the SN, and if necessary I can call Shreveport, the nearest dealer and plead my case. Just never know how helpful the guys will be.
Is there an Operating Manual in the machine? It should tell you relay locations. Pull the Reverse relay and test for voltage. If the test light doesn’t light up, it’s either the shifter switch on the column, or the wire between the shifter switch and the relay.
No, unfortunately there is not. Many of the machines we have come from auctions, where a lot of companies dispose of problem machines. Although cheap most of the time, some have serious issues. It's a rare thing to get much in the way of documentation, ops manuals or even rarer service manuals. I end up buying a few if if the repairs are going to be extensive or specialized. I cannot at this time positively identify the specific relay for R. If I could, I could check for supply voltage as well as switching, plus swap relays from the F circuit. Those I can ID by finger touch while engaging the transmission, but since the R shift is completely unresponsive I cannot. There are about 10-12 relays in the panel. Not identified, of course.
https://www.servicemanualbit.com/ I found this website googling at work when I needed a manual for a Nissan forklift. Had my job buy them to make sure it wasn’t a scam. Purchased a few from this site so far and haven’t had any issues. We’re pretty cheap too.
Thanks Jeff. I bought the 530 manual for 15 bucks and downloaded it along with a supplement. Total of something like 1700 pages I believe. I appear to cover this model. Holiday shipping slowed the parts coming in but I can check and verify the relays and a few other things before they get here now. I think I'll go to Kinko's or somewhere and get it printed and bound. And keep a copy on lappie as well of course.
The problem turned out rather elementary. One of the control solenoids on the transmission had come mostly unplugged, despite the retainer. It's awkward, and tough to access, but managed to do a wiggle test and found it. Plugged it all the way in and it's fixed. I don't know why the engineers didn't put an access panel on this machine so you could actually see these valves, but they didn't. Poor service thinking. Apologies for the late update, but the book it closed on this one, for now. It has some leaking cylinders, but they are going to wait a bit. This machine is equipped with a 60" claw/grapple and the guys are unloading timber for two firewood processors. After the season dies down, then it will get some seal attention. Thanks for all the help, guys!
Thanks for the update
And some guy probably unloaded that machine at an auction thinking it was going to need an expensive transmission overhaul.
Very likely the case. This is part of the auction game. As I recall, we got this machine rather cheap, so that seems like a reasonable explanation. The previous owner may not have had anyone capable of troubleshooting it or chose not to get someone who could, or perhaps if someone did have a look, either didn't find it or just told the guy it needed a new trans. Probably never know, but this was a zero parts cost fix, other than the F-N-R switch which did have some burned contacts that gave it erratic upshifts in forward, but that cost less than a hundred bucks and fixed what had been more of a nuisance than anything. The no reverse problem was not affected by that part replacement anyway. This one was nearly pure labor, and not really that much time. skata The thing about fora in general is that when someone posts up a problem and everyone tries to help, one of the worst things (to me) is that the readers, for possibly years in the future, never know the results. Was it fixed? Which suggestion was the correct solution? How does the story end? I used to lurk a lot of fora on different topics, and when I searched for previously presented problems, finding hanging threads was always frustrating to me. Even if the story didn't have a happy ending, at least the readers should know what happened. Maybe the machine burned to the ground....but we'd never know unless it was a closed thread. I promise to try and never leave an open thread here, although it may happen despite my efforts. I'm only human, and have typically a dozen running projects, some spread out a good bit, time-wise. It's not like a shop where I can just start a repair and not do much else until that one is complete. I jump around a lot, and some of it is not even heavy machinery related. I worked on a cardboard baler last week. And not all are presented here as trouble assistance pleas, but there is a lot to keep up with and my memory isn't what it used to be. But you're most welcome.