1954 Eagle. no reverse gear

[j sheppard]

1954 GMC eaglee detroit  diesel with 4 speed  manual trans. I have no reverse  gear.  Solenoid  is working lever at trans. ( I am factory certified  to rebuild saturn,saab and gm transmissions) will I have to pull this transmission?  I would welcome any suggestions!  : )

[luvrbus]

Must be a 4104 GM a question for you GM guys,there were no Eagles around in 54

[j sheppard]

The bus is a 4104 GMC Eagle. Anyone  have any manual transmission  experience?     

[gg04]

Have you tried manually shifting into reverse?  Solenoids wear out..Real easy to rebuild transmission if needed..rdw

[bs4104]

Have you shifted from 1st to 2nd while holding reverice button down???

[Charles in SC]

My bus is a 5303 but this may apply. When the tranny oil is cold and stiff it has a hard time letting the gears move. What I do is to turn the engine off, put it in reverse and then restart. I have also noticed that if I have not driven the bus in awhile sometimes I have to go to the rear and give the reverse thing a good shaking.

[j sheppard]

thanks for the help cylinoide is working properly and I'll ever is moving but it's not connecting to something in the transI think it is a Spicer trans but I will check it in the morning any ideas on where to get a manual for the trans. thanks for all your help. I can't wait to road test this good old girl but I better not until I get reverse fixed.  : )

[gg04]

Just because solenoid moves doesn't mean it's working.  Have someone push the lever all the way in as you go from 1st to 2nd...Then you will have a better idea what is wrong.rdw

[HB of CJ]

If memory serves (always suspect) the reverse shift can also be temperature related like how hot or cold the gear oil is.  In cold weather sometimes you need to idle in neutral with the clutch out for a few minutes to get the gear oil flowing.

Then when cold you need to be a little bit abrupt with the clutch and shifter and actually feel the shifter dogs grinding against the gear stops while you flip up the cover and then push in on that reverse gear button.   You will hear/feel it engage.  Clunk!

Opposite thing during very hot weather where the gear oil is ... well, always hot.  Then a quick clutch stab when in neutral then slowly place the shifter against first, then push the button and slowly engage first gear while pushing the button.

Takes a definite muscle memory.  After you have done it a bunch you will develop a feel for arranging all of this in the proper order and strength.  Sometimes when cold it takes a little bit of crunching for it to go into R.  Or ... do not back up ever!

If all fails, then if possible shift into first and drive forward just a few feet.  Repeat sequence.  Sometimes this works.

Hope this helps.  HB of CJ (old coot)

[j sheppard]

y'all are awesome thank you so much for the help! holding the reverse gear toggle switch and manually going from first to second we now have reverse!  : )

[Runcutter]

If you don't have an "Operators Manual" you might find that helpful.  GM published Operators Manuals for drivers, just as Maintenance Manuals for mechanics.  I just looked at Ebay.  While there are a couple of PD 4104 maintenance manuals available now, no Operators manuals.  They appear occasionally.  Remember to look for GM 4104, the word "Eagle" doesn't come into play.

If you don't have maintenance manuals, that'd also be a good idea, and I'd also add a Parts Book for the model to complete the set. 

The reason I'm suggesting this is that you said it worked when you went from first to second, with the reverse switch held down.  That is the right process -- covered in the Operators manual.  I can see someone going into first, throwing the switch and letting go, trying for second -- which doesn't hold the solenoid engaged. The reverse switch is a momentary contact switch, spring loaded I believe.

Also, a standard request for newer folks is to post their location (see my signature line) -- one of us may be nearby and can drop over to lend a hand if you need it.

Glad you got into reverse without having to get the wrenches out.

[bevans6]

Since you are a gearbox technician I'll show you what the inside of a similar transmission looks like, you might get a kick out of it.  This is the Spicer 4 speed trans, but the in-line model for an MCI.

You see the big gears stacked up, main shaft is on the right, middle and deep is the layshaft, and the straight cut gear all by itself on the left is the reverse sliding idler gear.  Input from the clutch is up top out of sight, and you see, in order from the top, helical cut third gear, second gear, reverse straight cut gear, and helical first gear on the very bottom.  Mainshaft reverse gear is the big straight cut gear and is also the sliding hub that is moved by the first/second shift fork to engage first and second gear - it slides on the 1/4" wide splines you can see and slides over the dogs that you see at the base of second gear.  When you grind a gear, what you are grinding are the tiny little 1/4" splines.  Except for reverse, when you grind reverse you are grinding the sliding idler gear.

When you engage the reverse solenoid it moves an internal shift finger so that the first/second shift rail is locked in neutral, and the shift rail for the reverse shift finger is moved.  When you shift into the second gear location on the shifter, you move the reverse idler gear up so that it engages both the mainshaft reverse gear and the layshaft reverse gear.  When you shift out of reverse, a spring returns the internal shift rod so that it again engages first and second.

Cheers, Brian

[j sheppard]

Richmond, VA.