Fixing (hopefully) the 4spd spicer that will not shift into 1/2 TODAY!

[Dlsnow]

I am about to pull the top plate off the 4 speed spicer today.  I finally have all of the linkage, solenoid wires and nuts/bolts off and am taking a break before lifting the top plate off the transmission.

Recap - After exiting the expressway I could not downshift from 3 to 2 - or to 1.  When I push into 1 or 2 there is not much travel and sharp resistance.  I checked linkage and other obvious things.  I spoke to every bus place in town and have had it towed (wow expensive) all over town to various places that will not touch it.  Some folks on the board suggested it to be an issue with the interlock pin/springs inside the transmission.  Apparently the interlock mechanism prevents shifting into 1/2 while 3/4 is engaged and vice versa (please correct me if i am wrong).  So I am taking the top plate off the transmission and looking it over.

I am fortunate to have both the parts and maintenance manual to compare.

Wish me luck and thanks for all the help.  I will be posting pictures of the inside of this transmission in a few hours.  I expect it to take a while to get this cover and gasket off.

[bevans6]

Good luck!  Lots of little nuts on studs, some are hard to get at.  Some are hidden by the clutch linkage, but aside from the clutch stuff you can take the top off without taking anything else off.  Tip - shift the box into reverse gear if you can, that puts the reverse shift fork in a place where it has clearance to come out so you can lift the top off.  If you need the manual pages let me know and I can photograph them and post them here for you.  If you take the shift rods out always be looking for little detent balls that tend to fly out and drop down floor drains or otherwise become lost forever.

Brian

[Dlsnow]

Thanks Brian - The top did come out - Very difficult as the issue I am resolving is that it will not shift 1/2 or reverse so that arm was in the way.

Great news (i think)...I was missing a bold that holds the 3/4 on the shaft.  If I understand the interlock mechanism then I believe the interlock thought I was in 3rd (even though I could shift 3/4 fine) and prevented 1/2 from moving.  When i pushed the 3/4 shaft into Neutral 1/2 now moves freely.

I am digging for the bold in the transmission right now

[bevans6]

A missing bolt is good news, I would think.  Some of the bolts are supposed to have safety wire on them so they can't back out.  Now that you can see what happens in there, it should get more obvious.

Brian

[Dlsnow]

OK - Problem solved - As far as I can see all the bolts have the wire through them (crude solution but obviously it works).

There is what appears to be a setscrew in the 3/4 holding the shift fork in place on the shaft. 

I drained the transmission fluid and found the setscrew.

Here is the problem now - I cracked the corner of the top plate of the transmission while removing it.

I could have it welded if that is necessary or I could jbweld it if that would do.

I spoke to Luke at US Coach to order the gasket and he said to use the high temp RTV as the gaskets arent really available.

Pictures
Here is what I first discovered the apperently missing bolt


Here is the setscrew that I found in the oilpan after draining it


And here is where I cracked the top of the transmission plate

[Dlsnow]

Dropped it off at the welder this morning.

I should have it back this afternoon.

[Dlsnow]

I did read in the manual to put it in  reverse before reinstalling it.

Any other advice?

[bevans6]

Make sure you torque everything that should be tight, safety wire the bolts with holes in the heads, and I would use Loctite primer spray followed by red loctite on those set-screws.  Use "the right stuff" as the gasket, let it set up for five minutes before you drop the lid on, torque the top bolts/nuts loosely, let it set over-night, and torque in down in the morning.  Change the reverse light switch now if you need to, it's impossible with the clutch linkage on.  Fully service the clutch linkage now, reset the height of the bolt that adjusts the air-assist cylinder, service the air-assist cylinder itself (On mine the  heim joints that mount the air assist cylinder were totally seized).  Obviously put the top on dry and make sure it shifts right before you button it up...     

Brian

   

[TomC]

I would drill and tap another hole on the other side of the crack to have it fully supported from both sides.  Good Luck, TomC

[Dlsnow]

Thanks Tom but the side that cracked is flush with the front so there isn't a lip to put a hole in. 

The good news is the weld job looks great!  Cant wait to dry fit and put this bad boy back in there.  Hoping the rain holds off.


Untitled by dlsnow97, on Flickr

[Dlsnow]

Back in business
I put the setscrew back in place with red locktite
Aligned the gears in the transmission (1/2 in Neutral Rev Engadged and 3/4 in Neutral)
Aligned the shift forks to put the transmission in reverse
Dry fit and shifted all gears - it worked !
Lifted it and laid down a 1/4 in bead of high temp RTV and let it set 5 min
Set the transmission top plate on and finger tightened the bolts
Let RTV cure for 1hr then 1/2 turn on all bolts
Let RTV cure for 24 hrs and torqued everything down
Reconnected all linkage, solenoids and everything
Took the old bus out for a drive and she shifted great.

So I can confirm in an MC-7 with a Spicer 4spd you can lift the top of the transmission off and pull it out of the bus without removing the engine.
Note you do have to remove the alternator to get access to the driver side of the transmission to remove some bolts.

Thanks to all you guys for the advise and words of encouragement and to Luke at US coach who seems to have all these parts committed to memory.

Were up and running and will be making the annual migration from Wisconsin to the Southwest in a week or so.

[bevans6]

You are just a gear-jammin' fool!  congratulations, good job well done.

Brian

[TomC]

Where in the Southwest are you going to be? Good Luck, TomC