928g transmission gear shifting problem

[promark51]

Hello all. Just want to say I appreciate all feedback and advice. This is a great resource to have and glad it exists. I’ve definitely learned a lot and saved some money in the past.
The problem: 3rd gear F/R doesn’t work. All other gears work.
Current status: located the shift solenoids and tested that they are energizing (screwdriver trick). They work properly except when I shift to 3rd. In particular, solenoid 3 and 6 are to activate in 3rd and they do not. I am that solenoid 3 does work as it is also used for 2nd gear and when in 2nd gear it’s magnetized and you can hear an audible click (most likely the valve moving).
Im thinking it’s something between the solenoids and the lever shifter in the cab. So I began to tear apart the shift lever but doesn’t seem to be much to repair in terms of a mechanical problem. I was hoping to open up the twist knob on the lever that allows you to select gear 1-4 but no luck yet. Seems there’s a metal pin that holds it together and I’m having difficult removing it. Was hoping once apart there is a contact or broken wire but nothing yet.
Anyone with some suggestions? Thoughts? Prayers?

 

[Nige]

First up may I suggest you post a Serial Number.
Second you might have got more views if you had posted it in the Wheel Loaders forum.
Thirdly do you have any Diagnostic Codes present on the Monitor..?

 

[Mobiltech]

If you know which cutches do what you can get away with switching leads at the coils from one to another which will point you in the right direction. What I mean is switch leads so that when the shifters in third it’s actually powering second gear coils. Just make sure you know which ones are which before you start.

 

[promark51]

Nige: thank for the response.
1. Alas, I do not have the serial number available at the moment. But will get it to u tomorrow.
2. Sorry about posting in the wrong section...I’m a bit rusty.
3. I do not have any diagnostic codes available. Not sure how to retrieve those?

Mobiltech: thanks for the advice. I’ll give that a try in the am.

 

[Nige]

You can retrieve Diagnostic Codes as follows. Note which ones are ACTIVE. This is important: -

Diagnostic codes can be displayed on the instrument panel. The codes can be viewed when the panel is in the service mode. To enter the service mode, begin with the key switch in the OFF position. Cycle the key switch OFF->ON three times within ten seconds. At the third cycle leave the key in the ON position. The displays are used to show active diagnostic codes and logged diagnostic codes. The MID is shown on the left display. The CID and the FMI are shown on the right display. When a diagnostic code is active, the letter "A" is shown in the left display. When a diagnostic code is inactive, only the code is shown. Each code is shown for several seconds. Then, the display will show the next code. After all the codes are shown, "---" will appear. The display will then cycle through all the codes again. To exit the service mode, turn the key to the OFF position for five seconds.



I suggest that you look at the Diagnostic Codes as a first step before frigging around with transmission solenoid connections. If there is a Code for the offending solenoid there will be a troubleshooting procedure for it, if the gear selector control is faulty there will likely be be a Diagnostic Code for that too.......

 

[promark51]

Thank u so much Nige. Now I see why the serial number is so crucial. This machine is a 1997 or 98....cluster looks nothing like your image. No displays on the cluster....all analog gauges. Sorry to waste your time. I should have waited till I had the serial number.

 

[Nige]

There were loads of alternatives for 928G. I just picked one at random to try to speed up the diagnostic process.
Don't lose hope. Even with an "analogue" machine there may well be a (relatively) simple way of extracting Diagnostic Codes. I just need the S/N to figure out how to do it.

 

[promark51]

S/N: 6XR00623 - Cat 928G -

 

[promark51]

Just a quick update.....went to get the S/N for Nige this morning off the machine, started the machine and let her warm up, selected 3rd gear and it works. Verified this by shutting off the machine, putting the key switch into the run position, put the shift lever into 3rd, jumped off the machine over to the solenoids/coils and confirmed that solenoid #3 and #6 are both magnetized.
The machine is in Michigan and our highs topped into the 60's this morning before a cold front moves thru this afternoon.....could this possibly be a temperature issue? We are normally in the 30's this time of year.....or a complete coincidence?

 

[Nige]

With that S/N we have to go "old school" to get the Diagnostic Codes, but it can still be done. It just takes a little longer.
If the problem comes back then reactivate this thread and we'll go from there.
I wonder if you haven't got damp in a connector or electrical/electronic component somewhere

 

[promark51]

Thank you Nige.....I am interested what this "old school" method would be. I have found some random diagrams/schematics online not specific to this machine.

 

[Nige]

If you don't mind I'm going to take a rain check on that. It means doing a fair bit of work pulling information out of disparate service documentation and then arranging it all in a way that it will make sense to you. If the problem returns I'll gladly invest the time & effort in doing it.

Basically what you have is a module external to the cab which can be "interrogated" to show up Diagnostic Codes.