JCB 3C MK3/mk111 no drive/wrong pump?

[Dieseldazzler05]

Ref:
Machine is a 3C mk3
MN: 3C111 139954/5

hey guys,

posted on here a while back about a machine I was looking at that had no drive, im refusing to buy it until the problems sorted! however I was down at the sellers working on it all day today to try an get it like the thing but no success! ,
ORIGINAL PROBLEM---once the TC oil got up to temp it dumped it all on the ground and that was that,no drive

its had a new crescent oil pump and a few new seals which has stopped the oil from the TC pouring out near where the T/C dipstick "Should" be (knackered bearing) however it still has no drive, and I cant figure out why?

one thing I did notice is that going by the manual the TC needs a "Pre-charge" from the Steering pump which should be the 5 pipe one (its name escapes me) however this has the earlier 3 pipe pump from the manual gearbox 3C mk2, also the relief valve block from below/beside the TC filler/dipstick tube and all associated pipework seem to have been removed,

so:...

can anyone confirm if the shuttle/TC needs this pre-charge from the steering pump in order for it to operate at all?

here's what I think has happened although I'm unaware if my theory's plausible!:

5 pipe steering pump failed-been replaced with 3 pipe one, pipes/relief valve removed from TC and holes fitted with blanks to keep the pre-charge- bearing in crescent oil pump disintegrated-lost oil and pre-charge-oil pump and seal replaced- new TC oil in but lack of correct steering pump = no pre-charge-resulting in shuttle not pumping/driving.

AND to top it all off the hydraulic oil is mixing with the engine oil and filling the whole engine right up!

any help much appreciated!

John

[TullyveeryClassicJCB]

The serial number you've quoted means your digger has the JCB Powertrain transmission but I'm nearly sure its the Build 3 Brockhouse transmission that only requires the pre charge from the steering pump.

[Dieseldazzler05]

ok cool, it doesn't distinguish any difference in the manual (workshop) that I have, just that the TC machines have the pump with the pre charge and the manuals have the normal 3 pipe one, I called JCB today Dundee and Glasgow HQ who both denied having any knowledge about the steering pump giving a pre-charge to any of the 3C Torque range of machines ? and went as far to tell me that they had no idea where I was getting such info even after multiple times of me telling them it was from their manual! must have been a Monday morning thing,

although both of them did say its most likely the "dump" pedal valve stuck in the dump position on the inside as the bit on the outside works fine,

cheers for your reply!

[TullyveeryClassicJCB]

I've seen the power steering pump with the five hoses that you are talking about and they were all on Brockhouse Build 3 machines. Your manual maybe was before Powertrain came in.

[Dieseldazzler05]

That's a good point! Although my manual from here is mostly the same but the "to" "from" machine numbers are much farther apart, strange one, I guess they just went with what they had at the time which would explain why the manual goes through all the different parts possible!

[philwheelton]

The Brockhouse transmission has the pump as part of the power steering pump ,your serial no relates to the Borge warner shuttle it has the charge pump in the bell housing on the front of the unit driven direct by the torque converter and they do need to be set , the dump spool can go out of adjustment and stop driving.

[essexpete]

If you have the the torque converter shuttle box + 4 sp gearbox with short stubby prop shaft you have a build 5. AFAIK there is no conection whatsoever between the hydraulic circuit and the transmission. There is an internal charge pump that supplies oil to the system.