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JCB 3CX4T powershift no 2nd gear in fwd

Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
I have a 2012 JCB Powersift 3CX4T 4 speed fwd and reverse, electric solenoid control. I do not have 2nd gear in fwd, or 4th(I think 4th needs speed control and I dont have the space for the speed test).
In forward I have 1st and third, reverse I have 1,2,3,4.
The column selector lever was sloppy(4000hrs) and I replaced it thinking this was most likely the issue. Alas, it was not. So definately dont have 2nd in fwd. Any tips on what to look at next. The solenoids are in a place that are virtually impossible to reach.
 

jcb jeff

Senior Member
Joined
Nov 23, 2014
Messages
394
Location
United Kingdom
I would say you need to check to see if you got a solenoid gone down or micro relay if controlled that way. Need serial number to tell what box is in yours.
Need to start with basic fuse ,relay ,wiring harness and solenoids first.
Solenoids fail you would normally have 2 engaged at any one time to make drive work.
It could be forward high or forward low solenoid issue or depending on gearbox layshaft or mainshaft solenoid.
If you take a pic of valve chest on gearbox and a mc serial number i can pin point which solenoid you need to look at.
 

Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
Thanks Jeff. Serial number JCB3CX4TJ02019533(could you let me know what the actual serial number part is, supposedly last six digits but that starts with a 0 and trying to find manuals/parts using that number doesn't match) It is the 4spd powershift, As far as I can tell the forward high clutch is not working. I removed the Us solenoid and applied 12v to it on the bench, and it was clicking as I assumed it should. I did a half assed voltage output test on the connector to Us and got 13v, but it seemed to climb to that point, not instant, but it was a poor check with poor contacts working in a very hard to reach area, so that check should ideally be redone. The relays appear to be the once behind the steering wheel cover, as I can feel the bank clicking.
 
Last edited:

jcb jeff

Senior Member
Joined
Nov 23, 2014
Messages
394
Location
United Kingdom
Hi drop the first 0 off and try that.Does you valve block look like this?
Try removing another and swap it with a none good one and try that.
The gears are controlled by an ECU behind steering coloum ,you will have a input from speed sensor on gear box to autoshidt but you should get 2 nd gear though.
Do you have any beeps when you first ign on or start?
 

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Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
Ok, I pulled the transmission out, I found some serious overheating on the layshaft pack/housing. A baffling find is that x5 of the solenoids have a dead short within themselves, and only x2 working. The old gear selector level had no detent between 2nd and 3rd, and I had replaced it. But not sure how x5 are not working. These are $250 a piece, whats the opinion on knock off solenoids? I tend to be an OEM parts person, but thats a lot of $.
viW-K1h3GZg0j_TwPG3u8JyltcjHmUbkAb5WiTuiPjoH0yVLDVr7TqZntQk3B1F4OyIFa0HAkrHQ6lqxABlD1ED-H-Fj3Vw4NvDhn3KiXWKaOjVaz25Far6k78PqBhfoxcAEVt3Zzn9g6s-CpFLPpTAZ3Nwq_Ka8M9sNl-_dtTfN8hw_Awd86buHcqF1Vp8asfo0uX1UYAi_5jjMdLwwvGBpu9uOVAs-rZAA1IKNgR_lIyzQYIjcvht-HUKajIYZ2xKpTE-GDf_CoNVXfBgeFmiWfsJVBc_Ma1IIHmlh3yKVSzCbSmI44zs_D3rU9BZtwOG5szzAFKIlOQGHrjJ8iBYK-FUY-TiouJj6hgO1nND1VqqY4E_EAR_xQgpJYK7xXwQ5Zu4r5gSGh23rYeRFSV_8ACXD3JZE8Ca-OllFyheElQyuUAef_kWVlfKcgHCI-vVtG6N6MsDg3x7A0iB1Obn3RDDiqgya60O4hDiw-XPu5o3uzCOb5RAeoQ-NuFgXP7P5YhQtPCuFeU0n3Z_p03-K6bZ87Rn3l5bdlOniXERiubeK23ZGt1C7CAtUwTFlvdQJPn767Qpp_7tMXDZtUidcnAcuySIJiufnLB_q5o8_5r5dimVHE4QA_bMOOz4z2Wc6I3JARO8zpTK7CcDcMFP7i1__5UgUV2py4WK9mxWVyLnuCTf0uoNiy8y-oQ=w194-h258-no
 

skata

Senior Member
Joined
May 10, 2007
Messages
1,541
Location
midwest
How are you testing them for short? Ohm meter? It should be very low. Maybe 3 to 20 ohm range ?
But it's kind of odd for that many to burn up.
If so, I would not hesitate to find aftermarket solenoids. It's not like jcb makes them themselves ...
But as for burning up, I'd check the clearance and seals on the shaft to make sure there's no leakage. Use an air gun to pressure test, like in the video above.
 

Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
How are you testing them for short? Ohm meter? It should be very low. Maybe 3 to 20 ohm range ?
But it's kind of odd for that many to burn up.
If so, I would not hesitate to find aftermarket solenoids. It's not like jcb makes them themselves ...
But as for burning up, I'd check the clearance and seals on the shaft to make sure there's no leakage. Use an air gun to pressure test, like in the video above.

I applied 12v to the pins, and its all sparks on contacts and no valve actuation. Superweird. I will check clearances etc on shaft. Installing all new O-rings etc on piston as well as clutches
 

jcb jeff

Senior Member
Joined
Nov 23, 2014
Messages
394
Location
United Kingdom
Hi
On testing the solenoids make sure the + and - are the correct way round or they dont seem to like being wired the wrong way.
As far as the clutch packs when you rebuild them soak the friction discs in the trans oil first before installing.
Have you got plastic or metal pistons if plastic replace them with metal ones .
If you send me serial number of machine or the id from the gearbox plate i can tell you what your clutch pack clearances are to be set at.
Jeff
 

Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
Thanks Jeff, serial is 2019533 2012 3cx-4t, I have the metal pistons, I am soaking the plates in JCB oil. I have noticed on the x2 solenoids that work that they are polarity sensitive, the rest are dead shorts. I have found some online for $60 that seem the right fit, but will check once i physically have them.
 

Bearhead

Active Member
Joined
Apr 20, 2018
Messages
42
Location
Boone, North Carolina
Thats great. thanks. From my measurements im getting around 2.1mm float. I dont have a dial indicator but a good vernier/caliper. Just waiting on few more parts etc.
 
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