I have a new to me Cat 908M s/n H8801419 with 2 issues I need help with. Issue 1 - quick coupler lock is inoperative. It has a skid steer style quick coupler with a hydraulic lock. When activating the switch in the cab, the lock hydraulic cylinder doesn’t move. There is however a hydraulic leak somewhere up under the cab that occurs when the switch is activated. I haven’t tracked the source of the leak down yet. I could use a hydraulic and electrical schematic. Issue 2 - the transmission will not go into high speed. I have the high speed or “speeder” transmission. Both low ranges work fine, however I cannot get it to go into high speed. With the transmission F/R switch in neutral and foot on the brake, when I push the high speed switch, the black gear symbol on the dash comes on for a second or two, but then goes back to low range. One time when I tried it, I got a gear grinding noise for a second and it went back to low range. No warning lights on the dash in either switch position. I will probably need someone with Cat ET to plug into it, but I thought I would ask if there is anything simple I could check. I haven’t dumped the transmission oil yet, but that’s on my list of things to do. Any help is appreciated!
Check your message inbox. The attached is all I could find in regard to the speeder transmission.
Thank you, I appreciate your assistance!
Thanks to Nigel’s help I was able to get the coupler working. After checking the wiring to the solenoid, it turns out there was nothing wrong other than the solenoids were stuck. Cycling the switch a few times got them unstuck. And there is no hydraulic leak in the coupler system. The hydraulic leak is most likely from trying to activate high speed on the transmission. I’m not sure the two speed low speed is working correctly either. With 2F showing for the speed on the dash, it maxes out at 6MPH, which according to the specalog is the max speed for 1F. There are no leaks when in low speed, so maybe the low speed issue is another stuck solenoid. I need to get under the cab (where the hydraulic leak is coming from) cleaned up to chase down the leak. It’s a black, greasy mess. Hopefully, the transmission problems are dues to the leak and/or the solenoid.
Looks like the high speed issue was also a stuck solenoid. Got the under cab cleaned up, but still chasing the hydraulic leak. Of course it’s up high under the cab and not something obvious… I believe this machine was used at a landscape supply company loading bark mulch or similar products and there is fine wood dust everywhere along with compacted, oil soaked wood dust in the engine bay and under the machine. It probably never changed implements and always ran in one gear, which would explain the stuck solenoids. That and the 21,000 hours it has on the meter. Oh and the A/C compressor is seized up.
It sounds as though some time spent pressure washing may well be in order.
As is sip my coffee......did you say 21,000 hours on a CAT 908M? If that is correct that makes me happy! (have a 2015) I could see those on the "bigger Cats", never heard of 21K on a compact!!!
For sure! I spent several hours yesterday with degreaser and the pressure washer.
Looks like I mispoke - it is 20,403 hours. The odometer is showing almost 31,000 miles. It was built in November of 2016, so not quite 10 years old.
I am baffled! Maybe Nige and others can chime in, I don't want to hijack this thread, BUT ...This is just unreal! What did that machine do in a previous life? 24 hour operation? Does it have the original engine? How is the rest of the machine looking? But Nige and others, have you ever seen a compact loader with this many hours? (Cat, Deere, Case, etc.) Thanks for the picture! And good luck going forward! Keep us posted!
I do not know for sure what its previous life was, as it’s an auction machine. From the clues I could find on the machine, it appears it was used at a landscape supply company loading bark mulch or similar products. It looks like the center pivot was replaced at some point as there are newer looking bushings in it and it is tight. I think the motor might be original. It starts easy and feels strong, but it does have some blow by. Hydraulics are strong. The bucket has a lot of heel wear, the grille and rear lights are all broken, the seat is worn out, and the front tires are shot, but it’s a pretty solid machine overall.
That's about 8.5 hrs/day, 5 days/week, 50 weeks/year since it was built... I'm guessing here, but on that size machine if those are actual hours it must be because the operator started the machine at the beginning of the day and let it idle all day... Although I can't see the original engine lasting that many idle hours either... Maybe someone here knows of an application where this size machine works accrue that many actual working hours? This is interesting...
The odometer is also showing over 30,000 miles. I didn’t see a reman tag on the engine, but I didn’t look too hard for one.
You'd need to find a Serial Number plate on the engine to determine if it is original or not. The plates in your photo don't contain a S/N. The original engine Serial Number fitted to that loader was 8GS3891. A thought from left field. I wonder if someone was messing with the hours on the Monitor Panel.? 30k miles on a wheel loader in 20k hours does not seem exactly logical.
Here's a nugget supplied by a contact of mine. It appears that the hours may well be genuine after all if it was at almost 12k four years ago. "From the sale date Sept 2017 up to the last Cat service record in Sept 2022 it put on nearly 11,700hrs consistently with the same dealer with no major repairs."
Looks like the motor has been changed. Current s/n is 8MJ2673.
Thanks for the info!
Very impressive....
Not really a surprise. I reckon the engine manufacture dates from somewhere around the 2021-22 time frame but it could easily have been installed way later than that. Engines with Serial Numbers beginning 8LSxxxx were being installed in machines at the end of 2020. 8MJ2673 is obviously newer..
Making slow progress, but it is progress. After many, many hours of scraping, degreaser, and hot water washer, I finally have all the reachable “gunk” cleaned out from the engine bay. In some places it was over 6 inches (130mm) thick! I got the engine oil and filter changed and the hydraulic oil and filter changed. Next up is transmission oil, axle oil, hub oil, and fuel filters. The switch between high and low on the transmission is still temperamental, but I want to see if changing the oil makes any difference. I think the one hydraulic leak is coming from a hose up under the cab. I need to trace that out better, but if it is a hose, that should be fairly easy to resolve. Here is just a small sample of the gunk that was every where, some places with more oil than others. Overall, for a compact machine with over 20,000 hours, it’s in pretty decent shape. So far I am into it about $1500 in parts, oil, and filters (with most of that being Cat oil and filters).
That is awesome, keep us posted!
Forgot to add, the engine oil drain plug, hydraulic oil reservoir drain plug and hydraulic filter drain plug are all magnetic and none of them had any metal on them. The hydraulic filter was very dirty.
All that flammable dust mixed with oil must have made that machine a major fire risk, especially around hot engine components.
Changed the transmission oil today. It was pretty low, but no major metal on the magnets. All 3 transmission positions are working and shifting smoothly now, I think they just needed some exercise. The female hydraulic quick connector on the loader wouldn’t lock, but liberal use of penetrating oil got it freed up as well. I was going to change the rear axle oil (and I may still do it), but it looked really clean and it was full. Still need to check the front axle and hub oil. Spent another hour trying to clean the top of the transmission and hydrostatic motor to chase down the leak. I think the oil leak is coming from the top of the hydrostatic motor. Hopefully it’s just a loose fitting or a bad o-ring.
Two separate issues on your 908M (H8801419). Here’s practical guidance based on common failures for this model. Issue 1 – Quick Coupler Lock Inoperative + Leak When Switch Is Activated The skid-steer style hydraulic coupler lock is controlled by a cab switch that energizes one or more solenoids. These solenoids direct oil to the lock cylinder. Most common causes on these machines: • Stuck coupler lock solenoids (very frequent after the machine sits). • Wiring/connector problem to the solenoids. • Actual hydraulic leak in the lines, fittings, or cylinder under the cab/platform when the circuit is pressurized. What to check first (no schematic required): 1. Locate the coupler lock solenoids (typically near the implement valve or under the cab/platform area). 2. Have a helper activate the cab switch while you listen/feel for the solenoids clicking. 3. Cycle the switch rapidly several times. Stuck solenoids often free up this way and the lock starts working. 4. While the switch is held, carefully inspect under the cab for the source of the leak (fittings, hoses, or the lock cylinder itself). Clean the area first so the leak is easier to spot. 5. Check for voltage at the solenoid connector when the switch is activated (should see battery voltage). If the solenoids click and there is still no cylinder movement, the problem is hydraulic (stuck cylinder, internal leakage, or blocked line). If they never click, focus on the switch, wiring, and fuse/relay. A Cat dealer with the serial number can supply the correct ones (commonly in the UENR5406 / UENR5407 / UENR5409 family for the 906M/907M/908M). Issue 2 – High Speed (“Speeder”) Will Not Engage Low ranges work, but high range only flashes the gear symbol briefly then drops back to low. Occasional grinding suggests the high-range clutch or shift mechanism is trying to engage but not completing or holding. Simple checks before needing Cat ET: • Transmission oil level and condition (check hot, on level ground, in the correct range). Contaminated or low oil is a frequent cause of shift problems. • Confirm the high-range switch itself is sending a clean signal (if you have a multimeter, check continuity/voltage while pressing it). • Listen/feel for the high-range solenoid clicking when the switch is pressed (with FNR in neutral and brake applied, as you described). • Check for any related diagnostic codes on the display even if no warning lights are currently on. Grinding + temporary symbol illumination usually points to either: • Insufficient clutch pressure (pump, filter, relief, or internal leakage), or • A solenoid/sensor/calibration issue that the ECM aborts. Changing the transmission oil and filter is a good next step. After that, Cat ET is the most efficient way to read codes, monitor solenoid currents, and view speed/range sensor data in real time. If you can report what you find on the coupler solenoids (do they click?) and the condition of the transmission oil/filter, more targeted advice is possible.
Thanks for the input! I have most of the issues solved (see my previous posts), except for a hydraulic oil leak from somewhere on the top of the hydrostatic drive motor.
Merci d'avoir fourni le numéro de série (908M / H8801419). Voici le détail des vérifications à effectuer pour chaque problème : Problème n° 1 – Verrouillage du coupleur rapide défectueux et fuite Test de clic des solénoïdes : Demandez à quelqu’un d’actionner l’interrupteur de la cabine pendant que vous palpez ou écoutez les solénoïdes de verrouillage de l’attelage sous la cabine/plateforme. Vérifiez si vous entendez ou sentez un clic distinct. * Déblocage des électrovannes bloquées : Si la machine est restée inactive, il arrive fréquemment que les électrovannes se bloquent. Actionner rapidement l’interrupteur à plusieurs reprises permet souvent de les débloquer. * Localisation de la fuite : Commencez par nettoyer la zone sous la cabine. Tout en maintenant l’interrupteur en position action, inspectez les conduites, les raccords et le cylindre de serrure afin d’identifier la source exacte de la fuite de liquide. * Vérification de la tension : Débranchez le connecteur du solénoïde et vérifiez la tension de la batterie à l’aide d’un multimètre lorsque l’interrupteur est activé. * Vérification : Si les solénoïdes émettent un clic et que la tension est présente, mais que le vérin ne bouge pas, le problème est d'ordre hydraulique (vérin bloqué ou conduite obstruée). En l'absence de clic ou de tension, vérifiez le fusible, le relais ou le câblage de l'interrupteur. Problème 2 – Défaillance de l’engagement à grande vitesse (« accélérateur ») * État du fluide : Vérifiez le niveau d’huile de transmission à température de fonctionnement, sur un terrain plat. Inspectez l’huile et le filtre afin de détecter toute contamination ou présence de débris métalliques. * Codes de diagnostic : Vérifiez l’affichage de la cabine pour les codes de diagnostic actifs ou enregistrés lorsque le symbole de vitesse clignote. * Vérification du solénoïde et de l'interrupteur : assurez-vous que l'interrupteur envoie un signal propre et écoutez le cliquetis du solénoïde de gamme haute lorsque l'interrupteur est activé (avec FNR au point mort et frein de stationnement serré). * Vérification : Si vous entendez un grincement accompagné du clignotement du symbole de vitesse, il est probable que le calculateur moteur interrompe le changement de vitesse en raison d’une pression d’embrayage insuffisante ou d’un défaut de capteur/d’étalonnage. Si vous pouvez nous indiquer si les solénoïdes du coupleur cliquettent et à quoi ressemblent l'huile/le filtre de transmission, nous pourrons déterminer la cause exacte !
Thanks for providing the serial number (908M / H8801419). Here is a breakdown of what to check next for each issue: Issue 1 – Quick Coupler Lock Inoperative & Leak * Solenoid Click Test: Have a helper operate the cab switch while you feel or listen to the coupler lock solenoids under the cab/platform. Check if you hear or feel a distinct click. * Freeing Stuck Solenoids: If the machine has been sitting, solenoids frequently stick. Toggling the switch rapidly back and forth several times can often free them up. * Trace the Leak: Clean the area under the cab first. While the switch is held active, inspect the lines, fittings, and lock cylinder to identify the exact source of the fluid leak. * Voltage Check: Unplug the solenoid connector and check for full battery voltage with a multimeter when the switch is activated. * Verification: If the solenoids click and voltage is present, but the cylinder doesn't move, the issue is hydraulic (stuck cylinder or blocked line). If there is no click or voltage, focus on the fuse, relay, or switch wiring. Issue 2 – High Speed (“Speeder”) Engagement Failure * Fluid Condition: Check the transmission oil level at operating temperature on level ground. Inspect the oil and filter for contamination or metallic debris. * Diagnostic Codes: Check the cab display for active or logged diagnostic codes when the gear symbol flashes. * Solenoid & Switch Check: Ensure the switch is sending a clean signal and listen for the high-range solenoid clicking when the switch is activated (with FNR in neutral and park brake set). * Verification: If you hear grinding accompanied by the gear symbol flashing, the ECM is likely aborting the shift due to insufficient clutch pressure or a sensor/calibration fault. If you can let us know whether the coupler solenoids are clicking and what the transmission oil/filter look like, we can narrow down the exact cause!
I appreciate the input, but both of those issues have already been resolved.