Cat 908M multiple issues

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!

EK701 said: I could use a hydraulic and electrical schematic. Click to expand... Check your message inbox. The attached is all I could find in regard to the speeder transmission.

Nige said: Check your message inbox. The attached is all I could find in regard to the speeder transmission. Click to expand... 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.

EK701 said: 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. Click to expand... 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!!!

Nige said: It sounds as though some time spent pressure washing may well be in order. Click to expand... For sure! I spent several hours yesterday with degreaser and the pressure washer.

512high said: 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!!! Click to expand... 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.

EK701 said: 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. Click to expand... 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!

512high said: 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! Click to expand... 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.

512high said: 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! Click to expand... 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.

EK701 said: I didn’t see a reman tag on the engine, but I didn’t look too hard for one. Click to expand... 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."

Nige said: 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. Click to expand... Looks like the motor has been changed. Current s/n is 8MJ2673.

Nige said: 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." Click to expand... Thanks for the info!

Nige said: 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." Click to expand... Very impressive....

EK701 said: Looks like the motor has been changed. Current s/n is 8MJ2673 Click to expand... 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).