JCB 3C Mk3 Powertrain - Shuttle problem & Oils Needed?

[philwheelton]

Yes 25 thou is just over 1/2 a mm , you should be able to push the spool in that far ,it is spring loaded to push out .

[Wadhampark]

Hello Phil and Pete,
Just to let you know that it was the dump spool causing the problems.
Somehow the rod which connects to the pedal had got bent slightly so the spool was out a little all the time. A few turns on the nut to adjust it and it now has plenty of power in forward and reverse.
There is a "whine" when reversing but it seems from reading other posts that is very common on Powertrain models.
Thanks for all your help and advice.

[spy290]

Hi All,
Sorry to resurrect this post.
Im having this exact same problem with my JCB 3C Mk3 powertrain.
The old girl when cold will move forward and back, but after around 10 mins she looses all drive.
I have checked the oil level (while running) and is fine.
The type of oil used is ATF Dexron II
I have played with the dump spool (adjusting it) and still the same problem.
Am I now looking at a very expensive purchase of clutch plates/box rebuild or is there something else that needs to be checked first?
Could it also be the torque converter that needs replacing?

Thanks in advance

[essexpete]

Steve I think you really have the wrong oil in there. That era of shuttle did not usually use an ATF. Now whether or not that is the propblem might be debatable. The symptoms are a bit like that of a worn components that become more 'leaky' as the transmission warms up and tolerances increase.
It could be leaking clutch packs or a poor charge pump for instance. I suppose there could be a fault with the converter? What you really need are some pressure checks run by someone with the right kit and knowledge. Some on here might help you with the pressure figures and location of the test points.

[spy290]

Essexpete, Do you know what oil I should be using?
The Gearbox serial No. is: 12731/579/129
The T/C serial No. is: 54
The Axel serial No. is: 01044

[spy290]

Essexpete.
Would this be the correct oil for the shuttle box:
SAE 10W Straight Monograde Engine/Hydraulic/Transmission Oil?

[essexpete]

That might be the one but I would try to check with a supplier.

Morris list this

https://www.morrislubricants.co.uk/prod ... matic.html

Could not see under the 3C 111 but under an old telehandler 520 -2

Q8 : Q8 TO-4 Fluid SAE 10W (From -10°C to 35°C)

[The Haulier]

Hi ,I have a mk3 3c power train and Iam just doing the rear bearing and seal on the gearbox ,however I didn't pay attention to whichway round the oil spinner went below ,( presuming that's what it is )looks rather like a worm gear ,one side is slightly different to the other ,I will try to post a photo later ,any help much appreciated,thanks Dan .

[Camelot]

Hi Everyone,

I'm new to the forum and looking for some help, I have a 1984 JCB 3CX (the old by wire type) and it's got the same problem's mentioned in this thread. no forward/reverse. I bought some oil and when I came to undo the drain plug the O ring washer had perished so the sump was almost empty, I have filled it back up to the correct level and replaced the O ring and now it's really strong in reverse but no movement forward. If I lift the back wheels off the ground then they will spin in the forward direction but nothing when coming into contact with the ground. Is there any type of additive I can put in the oil to give more grip to the clutch plates? and if not or if this doesn't work are there any video's on how to replace the clutch pack, I live in part of Australia where I am not going to find someone who will have done this job before, so I will look to do it myself rather than pay for someone to learn on the job.
Cheers Nigel

[essexpete]

Just to be sure, have you got the non electric shuttle lever? Did you check the oil level while idling or immediately on stop? The symptoms do sound like a problem with the forward pack as you have reverse.