2006 Pajero 3.2 GLS (Gen3) knocking noise when central diff lock is engaged
Posted: Wed Jul 11, 2018 8:52 am
Hi Guys. This forum is always a great source of valuable information, but I couldn't find any related threads to the noise I am experiencing.
The vehicle:
2006 (Gen 3) Pajero 3.2 DiD (4m41) SWB GLS with autobox and central diff lock. Mileage: 192000km. I bought the vehicle with full service history at 120000km, and have maintained it myself with the help of this forum and the Heynes Pajero Maintenance Manual (https://haynes.com/en-au/mitsubishi/pajero/1997-2014) and some other resources made available through these forums.
The issue:
Actually, since I bought the car, this issue has persisted, but it's never given me a headache and I'd like to put my mind at ease with the help from some gurus here.
When I am driving in sand and need to use 4HLC or 4LLC, I experience a single clunk / knock when transitioning between forward and reverse. It only happens once per cycle. For example, if I am in forward, and need to reverse under strain / load, then the vehicle emits a single clunk when I initially start reversing. It reverses fine, and I do believe that the central diff lock is engaged (due to the fact that it helps and I get out of sticky situations, but I can't actually confirm this). and there is no persistent clunking or knocking noise. When I then go forward again, under load, there's another single clunk / knock, and the vehicle moves forward with no persistent knock / clunk. If I were to reverse again, the knock comes back, once, and so on. This happens in both 4HLC and 4LLC.
All oil levels and grades are correct (front diff, rear diff, transfer case, autobox, engine) as far as I know.
I have thought of the following, but I'm looking for someone to shed some light.
1. A loose mounting bolt or worn mounting bush somewhere, but it could be anywhere (engine, autobox, ?). I have not done a thorough investigation, and I'm hesitant to say this is a probable cause, because I would expect it to happen in 4H also?
2. A problem in the transfer case. Hopefully this is not the issue because I don't want to have to open her up like that. If it is a problem in the transfer case, what is the likely cause? Backlash due to wear doesn't seem likely as I wouldn't expect such a sudden, loud knock from that. The knock seems more likely to be the result of something in the drivechain suddenly slipping due to excess load, not some clearance being gradually taken up until meshing / contact occurs.
3. A problem in the front wheel drivechain, but who knows where. I'm thinking worn CV joint (inner or outer), U-joint, front differential, or where the drive axles or front driveshaft meet their mating flanges. I don't know, and it doesn't make sense to me that it only happens in 4HLC and 4LLC and not 4H.
If anyone has any ideas or has experienced anything similar, please assist. I don't think it's a critical issue, but I don't want to be in a sticky situation that then results in me destroying my transfer case somewhere deep in the bush...
Looking forward to the guru responses!
The vehicle:
2006 (Gen 3) Pajero 3.2 DiD (4m41) SWB GLS with autobox and central diff lock. Mileage: 192000km. I bought the vehicle with full service history at 120000km, and have maintained it myself with the help of this forum and the Heynes Pajero Maintenance Manual (https://haynes.com/en-au/mitsubishi/pajero/1997-2014) and some other resources made available through these forums.
The issue:
Actually, since I bought the car, this issue has persisted, but it's never given me a headache and I'd like to put my mind at ease with the help from some gurus here.
When I am driving in sand and need to use 4HLC or 4LLC, I experience a single clunk / knock when transitioning between forward and reverse. It only happens once per cycle. For example, if I am in forward, and need to reverse under strain / load, then the vehicle emits a single clunk when I initially start reversing. It reverses fine, and I do believe that the central diff lock is engaged (due to the fact that it helps and I get out of sticky situations, but I can't actually confirm this). and there is no persistent clunking or knocking noise. When I then go forward again, under load, there's another single clunk / knock, and the vehicle moves forward with no persistent knock / clunk. If I were to reverse again, the knock comes back, once, and so on. This happens in both 4HLC and 4LLC.
All oil levels and grades are correct (front diff, rear diff, transfer case, autobox, engine) as far as I know.
I have thought of the following, but I'm looking for someone to shed some light.
1. A loose mounting bolt or worn mounting bush somewhere, but it could be anywhere (engine, autobox, ?). I have not done a thorough investigation, and I'm hesitant to say this is a probable cause, because I would expect it to happen in 4H also?
2. A problem in the transfer case. Hopefully this is not the issue because I don't want to have to open her up like that. If it is a problem in the transfer case, what is the likely cause? Backlash due to wear doesn't seem likely as I wouldn't expect such a sudden, loud knock from that. The knock seems more likely to be the result of something in the drivechain suddenly slipping due to excess load, not some clearance being gradually taken up until meshing / contact occurs.
3. A problem in the front wheel drivechain, but who knows where. I'm thinking worn CV joint (inner or outer), U-joint, front differential, or where the drive axles or front driveshaft meet their mating flanges. I don't know, and it doesn't make sense to me that it only happens in 4HLC and 4LLC and not 4H.
If anyone has any ideas or has experienced anything similar, please assist. I don't think it's a critical issue, but I don't want to be in a sticky situation that then results in me destroying my transfer case somewhere deep in the bush...
Looking forward to the guru responses!