Help!!! Case 621b trans problem

[tightgtp]

:Bangheadi have a case 621b with no 1st and 2nd gear in forward and reverse. i have 3rd and 4th gear. i check power to my 5 solenid valves on the trans valve. in forward i lose M3, in reverse i lose M1. i also tried a good used for/rev. lever assy. and got the same result. i have talked to 2 local dealers. they have been very helpful. both think probably the ZF trans control module is the problem. but i want to make sure before i buy a $3000 module that isn't returnable. i have talked to ZF transmissions, they thought a problem with the declutch system, i tested and didn't find anything out of the norm. does anyone know if the declutch works on all gears? any info on any of my problems are greatly appreciated.:Banghead

 

[Cotterpin]

The only experience I've had with ZF trans problems is on our HL760 Hyundai loader . It would suddenly just not move , tech came out and checked the resistance on the 5 solenoids , finding one with low resistance and replacing
would fix the problem . This has happened several times , with different symptoms such as forward only no reverse , 3rd and 4th no 1st or 2nd , If I remember the solenoids are $100 + . I'd definitly check ohms and compare readings looking for the weak one . Good luck........

 

[tightgtp]

i did check ohms. all around 89. dearler said they in spec. thanks for info

 

[Chris5500]

I assume you have the transmission clutch pack chart since you are using terms like M1, M3 etc. Can you upload the chart or try and replicate it here please?

 

[tightgtp]

heres the chart, solenoids are on the left M1 on top M5 on bottom

 

[Chris5500]

Makes it alot easier to help now

:Bangheadi have a case 621b with no 1st and 2nd gear in forward and reverse. i have 3rd and 4th gear. i check power to my 5 solenid valves on the trans valve. in forward i lose M3, in reverse i lose M1. i also tried a good used for/rev. lever assy. and got the same result. i have talked to 2 local dealers. they have been very helpful. both think probably the ZF trans control module is the problem. but i want to make sure before i buy a $3000 module that isn't returnable. i have talked to ZF transmissions, they thought a problem with the declutch system, i tested and didn't find anything out of the norm. does anyone know if the declutch works on all gears? any info on any of my problems are greatly appreciated.:Banghead

Have you actually checked the current to the M1 and M3 solenoids or have you made the asumption that you are losing these by misreading the chart?

The solenoid and clutch that is common to both F1, F2, R1 and R2 is solenoid M4, check it with your DMM and look for any loose, broken, shorted wires etc.

I'm not saying it's definatley M4 but its alot more likely than 2 (or 4) seperate solenoids (M1 and M3 or clutch packs).

Have fun!

 

[tightgtp]

after first studying the chart i was convinced M4 was the problem, but after testing i found i always had voltage there and none at M1 and M3 when needed. ZF transmission told me that M1 and M3 are the directional solenoids.

 

[tightgtp]

:Bangheadi have a case 621b with no 1st and 2nd gear in forward and reverse. i have 3rd and 4th gear. i check power to my 5 solenid valves on the trans valve. in forward i lose M3, in reverse i lose M1. i also tried a good used for/rev. lever assy. and got the same result. i have talked to 2 local dealers. they have been very helpful. both think probably the ZF trans control module is the problem. but i want to make sure before i buy a $3000 module that isn't returnable. i have talked to ZF transmissions, they thought a problem with the declutch system, i tested and didn't find anything out of the norm. does anyone know if the declutch works on all gears? any info on any of my problems are greatly appreciated.:Banghead

i got the unit running today, i didn't have power through my declutch relay to the trans computer. everything works great

 

[tightgtp]

:Bangheadi have a case 621b with no 1st and 2nd gear in forward and reverse. i have 3rd and 4th gear. i check power to my 5 solenid valves on the trans valve. in forward i lose M3, in reverse i lose M1. i also tried a good used for/rev. lever assy. and got the same result. i have talked to 2 local dealers. they have been very helpful. both think probably the ZF trans control module is the problem. but i want to make sure before i buy a $3000 module that isn't returnable. i have talked to ZF transmissions, they thought a problem with the declutch system, i tested and didn't find anything out of the norm. does anyone know if the declutch works on all gears? any info on any of my problems are greatly appreciated.:Banghead

i got the unit running today, i didn't have power through my declutch relay to the trans computer. i thought the relay was supposed to energize when declutch is activated, but it works opposite my thinking. repaired the wiring and everything works great

 

[tightgtp]

i'm retarded! i wasn't done writing in my post before i posted it. anyone know how to delete a post.

 

[t-chnmypup]

Hey can u tell me which relay outa 4 is the one is the declutch relay. I kinda have the same problem but mine will kick in and outa gear then back in.

 

[tightgtp]

i think it was the middle relay of the three as soon as you open the relay/fuse panel. i had a big relay towards the front of the machine then two smaller ones.

 

[t-chnmypup]

Thanks i ordered a manaul but its not here yet. I've had more problem with the electical parts of this tranny than i've ever had before

 

[bignorms32]

Ive got a problem with an older trojan loader. anyone know why i would have good power in all the reverse gears but no power in the forward gears? someone said there are adjustments and even one on the converter??

 

[gggraham]

Watch those B series wheel loaders they had ground problems there are a couple spots where several ground wires come together. Take the nut off and all the wires, clean them thoroughly and put the nut back on. One is on the engine, one is on the frame near the center pin and one is I believe inside the LH electrical access door. The 2 Deutch(round) harness connectors that go together with a half turn on the LH side below access panel. Common for them to corrode take them apart and clean them too. The only other thing I can remember with the electrical was that the alternator light can on some units flicker at an idle. If it does install a capacitor on the alternator and it will stop the flashing.

 

[t-chnmypup]

Little more info on the electrical on this. There is a speed sensor on the left side that controls alot like not shifting over second,forward or rev. It also has some control over the valve solenoids through the computer. I found this out after readin the manual i got. Theres a ohm reading of 1080-1280.Thats for the past advice

 

[Tyler G. Dildine]

I've got a 721b with no movement at all. Replaced shifter all 5 solenoids ( $110 a piece if you Google enough). I rebuilt the wiring harness to the M1-M5 solenoids, my biggest issue now is the order of the solenoids. I've seen 3 different schematics from the Titan dealer, but no one knows for sure the right order. Any one have an idea?

 

[Coy Lancaster]

:Bangheadi have a case 621b with no 1st and 2nd gear in forward and reverse. i have 3rd and 4th gear. i check power to my 5 solenid valves on the trans valve. in forward i lose M3, in reverse i lose M1. i also tried a good used for/rev. lever assy. and got the same result. i have talked to 2 local dealers. they have been very helpful. both think probably the ZF trans control module is the problem. but i want to make sure before i buy a $3000 module that isn't returnable. i have talked to ZF transmissions, they thought a problem with the declutch system, i tested and didn't find anything out of the norm. does anyone know if the declutch works on all gears? any info on any of my problems are greatly appreciated.:Banghead

Check the speed sensor on left side of trans housing about midway. Should ohm 1000+. Be sure and not loose the washer on sensor if you need to replace it because it’s a shim for spacing.