Ok sorry in advance for the long thread but I’m trying to be through older case 621b the boss was running it and it lost all gears forward and reverse zero engagement whatsoever I’ve checked all my declutch circuits and sensors all good my neutral safety parking brake all good trans cut out relay functioning properly. All my shift solenoids ohm out 95to 115 depending on temperature I have good charge pressure at the valve body my speed sensor ohms out good my main buss connections are good grounds are good I have power and grounds were I should at the zf controller I have continuity to the shift solenoids the fnr lever is sending power correctly the zf controller you can hear clicking 3-4 times upon cycling the key from what I have read it is shutting itself off because it doesn’t like something it’s seeing in the readiness check also all solenoids click and cycle upon key cycle once but are receiving no voltage after I’m getting desperate guys hoping someone has ran into the same problem
Maybe its a bad key switch. A prime example where electronics has no place, on a loader transmission. Just wow ! Need to check for internally broken wires, meaning under the insulation. I've had that happen a few times on other vehicles.
Key switch fires off everything just like it should I have home, tested everything from the TCM all the way back to the main bus connections I’m really stumped. I found nothing wrong with this machine.
@Bigbert is our resident ZF go-to guy. Hopefully he will chime in.
Hi Zack, resp. MG2361, thanks for invitation. Zack, assume your loader got a ZF 4WG150 or 180 with EST25 box? Is there a display fitted in dash? Possibly not as you did not mention anything about fault codes. I'll share a description of EST25 in a PN.
I will post a picture of controller box tomorrow when I’m back at work I’m posting some screenshots of the manual for everyone lol
Diagram s and schematics
No displays in dash just a old school led location display on the side
It does appear to be a eat 25 controller and ergo 2 shifter
A relay clicking and staying on only means the control circuit is strong enough to make the contacts move to the closed position. It tells you nothing about the conditon of the contacts inside . Load testing the relays off with a known load like 5 amp, 7 amp, 10 amp bulb lets you know whether it will work in the real world with vibration and heat. Not saying you tested incorrectly, just saying what is a proper test for a relay, or even for testing wires. There has to be load, OHM meter test can lead you down a rabbit hole. Simon C
I will chime in, I have seen this before, If the controller does not see resistance from any one of the transmission shift solenoids, no movement. I would disconnect the plug to the transmission shift valve and ohm test the 5 solenoids, also check the internal harness, seen enough failures there that I used to carry a harness and a solenoid with me on the truck. Hope this helps!