Cat 938 wheel loader tranny issues stuck in first gear

[Cat938g]

I just bought a cat 938G with 5,000 hours with tranny issues it goes in forward and reverse FIRST GEAR ONLY it won't shift in any other gear and is strong in first.. Any thoughts at all as far as possible issues has anyone dealt with the same issue I'm hoping its not internal trans issues. I was told by an inspector prior to the auction starting that the trans was in working order shifted in all gears... It may be a intermittent issue or maybe something got unplugged by a shady buyer to get a better deal. Anyhow I am stuck with this unit and looking for some good news anything at this point would be very helpful thanks.

Serial#4YS00897
Model#938G

 

[kshansen]

Not familiar with that machine but see this instruction in the operators manual for the 938G:

Automatic Mode - To activate the automatic mode of the autoshift function, push the top of the switch prior to shifting the transmission into forward or into reverse. Select the highest desired operating speed. The control selects the proper transmission gear according to the version of the machine and according to the ground speed of the machine.

There should be a switch with AUTO in the middle os a picture of a gear, that part did not copy and paste.

It could be someone just st the "highest desired operating speed" to 1.

Have you found the operators manual that should be behind the seat?

 

[Cat938g]

I'm hoping this is the case. I won't be able to check to see if this fixes the prob or not till tomorrow I will advise tomorrow.

Any other input or similar experience with this issue would be appreciated so I can tackle all theories at once thank you KSHANSEN I'm hoping and betting you are right )

 

[Nige]

If you would like a download of the diagrams of the "Operator Controls" section of the manual then let me know. I would need at least the Serial Number Prefix of your loader to make sure I get the correct Operator Manual. If it is a Series I machine then the options are 4YS, 6WS, 8RS, or 9HS. For a Series II machine the options are B9Y, CRD, MSC, PHN, or RTB.

 

[Cat938g]

4ys
Thank you.

 

[Nige]

You now have 3 posts on the forum so you should be able to send Private Messages (PMs). Send me a PM with your e-mail address, I'll fire it off to you.
If you can't send a PM now make 1 more post and see if it works then.

 

[Cat938g]

Ok so I got into the machine got into first gear nothing in second right to 3rd and changed into forth.
No second gear power at all.
Any help would be great.
Is this a full tranny job or maybe just a solenoid? Anything would be great has anyone dealt with the same issues? Thanks guys.

 

[Nige]

PM me your e-mail address. I can probably rustle up the transmission test and adjust procedure, troubleshooting, and the electrical schematic as well. Is it missing second gear in both forward and reverse..?

 

[Cat938g]

Yes in forward and reverse.
But all other gears are strong as can be.

 

[Nige]

Each transmission clutch (6 in total) is controlled by a separate electrical solenoid valve. Try interchanging the complete transmission solenoid valves for 3rd speed & 2nd speed. The 2nd speed solenoid is fed by wires 975 White & 900 Purple, 3rd speed solenoid is fed by 975 White and 901 White. If your missing gear goes from being 2nd to 3rd then it's the solenoid at fault.

If that fails post back here and we'll get into looking for Diagnostic Codes in the transmission electronics before looking at the mechancial side.

 

[Cat938g]

I'll let you know once I try it.
Thanks.

 

[Catfan85]

I’m having this same issue, was a solution ever found? I’ve tried switching the solenoid with another one and that made no difference. Any help would be much appreciated!!