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3CX black cab: no drive

Posted: Wed Jul 06, 2022 3:29 pm
by QAnon
Hi All,
I'm looking at a 1984 4WD black cab 3CX which has sat for 3 years having lost all hydraulics. We found a blown steering hose which cured the hydraulics but it has no drive. It creeps maybe an inch but nothing more. Oil has been topped up (checked with engine running). There is a missing donut support for the intermediate driveshaft which would let that thrash around way too much. The owner is not sure when this came off.
-I'm not experienced with these machines so am looking for any pointers really...
-I'm wondering if the loose driveshaft may have massively damaged the drive?
-I read elsewhere here about possible failed clutch packs?
-I read about simple issues of broken springs to relief/dump valves? -not sure if these apply to this machine!
-Any other checks we can make before running away from this one..?
-Any experienced ideas at all are welcome! :D

Re: 3CX black cab: no drive

Posted: Fri Jul 08, 2022 8:52 am
by Jeremy Rowland
Hi Alec and welcome :wave: there is a wealth of information and skill on this site so somebody should come back to you with some good advice. :thumbup:

Jeremy

Re: 3CX black cab: no drive

Posted: Fri Jul 08, 2022 1:11 pm
by essexpete
Is the forward/reverse a small yellow stalk or a big chunky lever?

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 10:24 am
by QAnon
Hi Pete,
So we've got a cable operated shuttle, found the cable off! But now pretty certain the torque converter to pump seal has gone. We had reverse but no forward and after an hour or so adjusting and checking things we had no drive at all. Oil is pushing out between the starter and bell housing.
The odd thing is that the oil from the bell housing is milky, water contaminated (like that in the hydraulic system) but the tranny oil is clean. Is the converter fed from the hydraulics separate from the tranny? From the manual I thought it was powered by the tranny pump and oil?

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 11:19 am
by essexpete
There are far more knowledgeable folk on here than me and with luck some will comment.
Your machine must have the older Borg Warner T72 velvet shuttle. The oil is separate from everything else. The gearbox is separate with different oil. I amsurprised that the bell house weep appears different. There will be an oil cooler by the main rad (I am not familiar with the 3CX) and it may have internal damage causing cross contamination.
If you have reverse and not forward then you can assume that the torque converter and trans pump must be essentially working. It is likely that the forward clutch pack has failed. Either the piston seal or clutch plates to fault. I think it will be a shuttle out job for overhaul. When we have had these repaired all seals and plates were replaced along with a new pump. The cooler must be checked first before using after repair.

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 11:21 am
by essexpete
To add that the oil level is checked whilst the engine is idling.

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 1:22 pm
by gecko.cx
QAnon wrote:Oil is pushing out between the starter and bell housing.
The odd thing is that the oil from the bell housing is milky, water contaminated (like that in the hydraulic system) but the tranny oil is clean.

Not familiar with this machine, but thinking of options - have you checked the engine oil for contamination?

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 5:11 pm
by QAnon
essexpete wrote:To add that the oil level is checked whilst the engine is idling.


I see there's much debate on when to check oil.. the manual I'm using from here says "within 15 seconds of stopping the engine". Maybe I'll try both and see if there's any difference.

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 5:12 pm
by QAnon
gecko.cx wrote:Not familiar with this machine, but thinking of options - have you checked the engine oil for contamination?

Will do.

Re: 3CX black cab: no drive

Posted: Sun Jul 10, 2022 5:31 pm
by QAnon
essexpete wrote:There are far more knowledgeable folk on here than me and with luck some will comment.
Your machine must have the older Borg Warner T72 velvet shuttle. The oil is separate from everything else. The gearbox is separate with different oil. I amsurprised that the bell house weep appears different. There will be an oil cooler by the main rad (I am not familiar with the 3CX) and it may have internal damage causing cross contamination.
If you have reverse and not forward then you can assume that the torque converter and trans pump must be essentially working. It is likely that the forward clutch pack has failed. Either the piston seal or clutch plates to fault. I think it will be a shuttle out job for overhaul. When we have had these repaired all seals and plates were replaced along with a new pump. The cooler must be checked first before using after repair.


Thanks it is that trany according to the manual from here. We lost reverse too after a while. Am basing my assumptions on old posts on here with the same symptoms but appreciate this may not be the whole story. The cooler is a worry. Mine seems to be part of the radiator but the manual is unclear, maybe someone can clarify?