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Cat D5G dozer-- suddenly won't go. Brake light on. Just stopped/locked up

gaery123

Member
Joined
Aug 28, 2019
Messages
14
Location
PA
Occupation
Farmer
Cat D5G dozer
CAT00D5GEWGB00772
S#: *MHK02423*
Model 3046

DISCLAIMER--- I'm going to do the best I can explaining this because I'm a wife of a guy who is helping troubleshoot while trying to interpret a bunch of frustrated short ass responses from 3 guys about a broken machine and they are p/o'd. :)

Cat Dozer D5G was working fine, then all the sudden stopped moving forward.
Starts/Runs fine.
No pressure in the side case with the little valves that they can test.
E-brake light came on (i think it was e brake)
Voltage on alternator checks out good.
Solenoids checked out good
Has fluid in it.

Did a search and saw it's finicky about voltage so alternator and solenoids were 1st stops. They all seem to be okay though.

They are thinking either a plastic wheel that is enclosed that happens to be buried in the center of the machine is broken and needs ripped apart to even know if that's the culprit (a CAT familiar friend thought this possibly). Thinking this because there is no pressure in the valves forming so it's not spinning... OR they are thinking ECM because something in the back/bottom is testing a lower voltage and I'm not sure what that was (and it was plugged in when tested if that means anything to people that know what they are talking about).

Any other simple fixes to look into that would cause it to come to a halt randomly when working fine and not even under load?
Any thoughts/suggestions. It has 8000ish hours I believe, kept up and serviced well. Thanks for any insight
 

CM1995

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Jan 21, 2007
Messages
15,952
Location
Alabama
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Running what I brung and taking what I win
Have they load tested the batteries?

Probably not the culprit but we had a similar issue only to find out we had 1 battery going out.
 

gaery123

Member
Joined
Aug 28, 2019
Messages
14
Location
PA
Occupation
Farmer
Have they load tested the batteries?

Probably not the culprit but we had a similar issue only to find out we had 1 battery going out.
Thanks for the reply CM1995. Yes they did test the batteries. all good on that part.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
38,493
Location
G..G..G..Granville.........!! Fetch your cloth.
We’ve been here before - numerous times actually. This is the 2nd one in the space of a week. Kudos for posting the Serial Number BTW.

See the link below which should contain all the required information to test the machine and to probably confirm the failure of the drive coupling. D3G thru D5G the same information applies to them all. If the 8000 hours on the machine is correct then the coupling has done pretty well to last that long.

https://www.heavyequipmentforums.com/threads/d4g-lgp-parking-parking-brake-issues.120272/
 

gaery123

Member
Joined
Aug 28, 2019
Messages
14
Location
PA
Occupation
Farmer
Additionally if you do get to removing the engine the two attachments in Post #11 of the thread I linked above will both still apply to your tractor Serial Number.
Thanks Nige.
In my haste/desperate attempt to get the info out there for any responses, I did end up searching and found posts on here with all your resources and explanations! I apologize for the dup posts but I appreciate your expertise. I ended up sending screen shots and links last night from some other posts of your replies.

Unfortunately they are landing on the drive coupling plastic star teeth part. Your engine instruction pages will be most helpful now .
 

Greg P

New Member
Joined
Aug 17, 2025
Messages
4
Location
Texas
Gaery123, I was just wondering how much time it took to pull the engine and replace the coupler.
I have the same machine bought used, no service records, but looks to be well maintained with less hours 4800 and was going to change the coupler, as I think it’s the original one in there.
Just as a PM type repair.
Thanks
 

gaery123

Member
Joined
Aug 28, 2019
Messages
14
Location
PA
Occupation
Farmer
It took them probably 4-5 hours to get the engine out to access. Then they let it sit because they had to get the part the next day and it went together fairly easily and probably 3-4 hours they were back to operation. 2 of them were working on it and they had an excavator luckily on site to lift

They had found a YouTube video about it too. Guy did it in a day. The YouTube video was a bit older model but same concept and issue.
 
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