cat 416C no first or second gear

[Selby R Knight]

Nige
I made an error in above posts
CORRECTION # 6 has wire broken from coil ( upper solenoid)
#7 was the suspected problem ( lower solenoid) which has 10.3 ohms on the coil & has only 4.5 volts on the wire

 

[Selby R Knight]

I checked voltage going to solenoid #6 ( top with wire broken !!!) it has machine voltage 14.1
I do have the floor board removed but did not check voltage on any other solenoid

 

[Nige]

I got that. Either way I suggest measuring the voltage at all the other colis and see what voltage you measure. That would confirm that all the coils operate on machine voltage.

 

[Selby R Knight]

wire to solenoids #4 and #5 both have 4.5 volts ( key on , engine not running)
same voltage as #7 which was checked with engine running
solenoids 1,2& 3 not accessible

 

[Nige]

If you don't have easy access to the solenoid valves on top of the transmission then you could always open up the dash panel and get into the back side of the transmission controil unit.

I understand access can be difficult, that's why I suggested getting into the control on the cab and measuring there if the checking at the solenoids was not possible as a result of limited access.

I would suggest measuring the voltage with the wheels up off the ground, engine running and with the transmission engaged in a gear where that particular solenoid is used. It's not necessary to test in all 8 (F & R) speeds. The list below includes everything apart from #6 wihch activates the FWD.

In 1st speed forward you can test solenoids #4 & #7.
In 2nd speed forward - #5 & #7.
In 4th Speed forward - #5 & #1.
In 3rd speed reverse - #2 & #3.

 

[Selby R Knight]

with the dash opened I see switch's, relays & something that i do not recognize !
on far right of the panel, is that the transmission controller?
i'll attach a close up of it
If this is not the controller, what should i be looking for ?

 

[Long0]

Looks to me like you’re noise maker for audible alarms

 

[Nige]

If this is not the controller, what should i be looking for ?

My bad. I thought it was behind the dash panel and should have confirmed before giving you that info. It's actually mounted in the RH "battery box". See attachment.
Use the electrical schematic to compare wire numbers.

 

[Selby R Knight]

Thank you for the information on controller location and schematic , I have not checked further on the wiring situation because I was waiting to receive the new solenoid that was on order
Removed solenoid #6 from transmission , put it in bench vice , heated the nut & worked it loose. worked it about 1/2 way off before the shaft twisted off !!!! ( I had ordered coil only plus a complete solenoid)
Install the new solenoid , it screwed in easy with fingers for only maybe 2 turns , then it became stiff to turn . I worked it out & in until it was in and seated. Proceeded to install the coil on the solenoid, it seemed to be not tightening any more . though I had stripped it , so left like that .
Started engine , no forward or reverse gears , saw oil leak from transmission .
used a rag to wipe & see where oil leak was
The new solenoid was broken off---- guess I overtightened it and broke the solenoid shaft !
NOW I HAVE MORE SERIOUS PROBLEM
I used socket to unscrew the solenoid , but only the nut part came out . The plunger part of the solenoid is stuck in the transmission. can not pull it out with fingers. should i put vise grip on to pull it out or is there a bigger problem ? ( the old one had no resistance to go back in but new one did have resistance to screw in )
Sorry to be going on & on with details , but if anyone can get me out of this I think it is you !

 

[Nige]

You're going to have to get the broken part out as best you can. Just try not to drop any parts inside the transmission.

 

[Selby R Knight]

Finally have the spool valve from broken solenoid removed from transmission . I put the nut on the grinder and removed all external threads from it. That allowed the nut to screw in using the internal threads and again attaching to the spool valve. With #7 solenoid removed I was able to pry from top and bottom and get the jammed piece out.
NOW FOR THE CONFESSION The new solenoid was a replacement that I bought on Amazon for $265 . It looks same as the CAT solenoid ($336), except the taper at the end is slightly less. I now have a CAT solenoid which I have installed to replace the damaged # 6 solenoid . I now have forward and reverse , except in 1st &2nd ( same as when i started)
Will proceed with diagnosis and advise
THANKS FOR ALL YOUR HELP

 

[Nige]

Go back to my post above and check the output voltage to all 7 transmission solenoids at the control when different gears are selected as per below. All tests should be by back-probing the relevant connector(s) with the transmission wiring connected.

You will need the wheels off the ground supported with the stabilizers and bucket, and the engine running.

In 1st speed forward you can test solenoids #4 & #7.
In 2nd speed forward - #5 & #7.
In 4th Speed forward - #5 & #1.
In 3rd speed reverse - #2 & #3.

 

[Selby R Knight]

Sorry for my delayed response (again !)
After installing new solenoid had an oil leak from steel line on side of transmission
after waiting 2 weeks for parts I had the line welded yesterday.
we now have all gears working in F & R
As per your original diagnosis the problem was SOLENOID # 7 , controlling clutch #1
I am greatly indebted to you for your diagnostic information & especially your patience while we worked through it
Previously looked for assistance on this forum with no start issue . but never got such great help as with my transmission issue
maybe I'll repost that one !
THANKS FOR A SUCCESFUL DIAGNOSIS

 

[Nige]

Thanks for the update.
It is unfortunate that you had so many setbacks while doing the diagnosis & repair but unfortunately that is the price you pay when working on older machinery.
At least the fix was cheaper than what replacing a transmission control unit would have cost. Regarding that my apologies for steering you to the wrong location behind the dashboard when in actual fact it's in the battery box.

Previously looked for assistance on this forum with no start issue . but never got such great help as with my transmission issue. maybe I'll repost that one

You should. There are a number of electrical experts who I am sure can offer help. Just be sure to include as detailed a description as possible of the symptoms.