Center shaft stuck in differential

[markmakeitso]

Hello all,
Short story, grenaded center diff in my 91 MT AWD, trying to disassemble. Intermediate cover is off, transfer case is off, differential output gear and passenger side gear are out, as are pinion shaft and pinion gears. The center shaft (that protrudes to lock into t-case won't slip out towards the engine side, it slides about 3/4" then locks pretty solid. A tap on the bellhousing side frees it up to slide back towards the 5th gear side. In the center between 2 extremes it rotates freely, and when it locks it doesn't feel like splines engaging, more like a tapered fit locking up. I can work on getting some pictures if necessary.

There doesn't seem to be a good way for the center shaft to bind up like that, just the slight shoulder up into which the splines at the transmission cap ends are cut.

Attached are 2 diagrams from the factory service manual. Not sure why it's locked up in there to be honest, all the other times I've had ocenter shafts in or out they've come free with a tap once the check ball was removed. Could the center shaft or output shaft be bent, causing binding when attempting to slide it out? Anyone else had this happen when the center diff lets go?

Thanks for any help,
Mark

edit: added pictures, whoops.

 

[markmakeitso]

donniekak: Thanks for the PMs, will keep it in mind. Not super worried about the center shaft, as it has pretty worn splines anyway. Mainly just need it out.

Update: In addition to the center shaft refusing to come out the differential housing and side gear won't slip off towards the passenger side. Hammering on the center shaft didn't seem to do much, so I used a 3 jaw puller from case cover to center shaft. 3 longer bolts from case end to differential body allowed a gap to grab onto with the jaws: no luck. Even air impact to 140 PSI had no effect. Kind of stumped here, and trying to avoid screwing up a housing casting or bearings by applying more brute force. I'd rather not buy a used transmission to put in, but it's looking like that might be the way to go. Between needing a center diff assembly, possibly screwed up front output shaft, and inability to further disassemble this trans it's not looking real good. Anyone have any great ideas?

Side note: got an email notification of a post to this thread, but it never showed up. Anyone else see a message in between my 1st and this one? Weird.

 

[donniekak]

Take it out of the car. It's so much easier to work on that way.

 

[twicks69]

Take off car, sledge hammer shaft out.

 

[4pistons]

You'll have to beat it out!! Here's my bet: The side gear thrust washer is smeared like butter (It's soft) and jammed the side gear in the case half. I have my old one still on the shelf and it's broken in two from hammering it out of the center diff.

Rick - '91 GSX

 

[markmakeitso]

Hi twicks69, I was close to PMing you since you seem to weigh in on lots of transmission questions. Will probably pull transmission tomorrow and give that a shot.

4 pistons: Semi comforting to find out it happened to someone else. Did your center diff assembly also refuse to slide out of the transmission? Judging by the passenger side thrust washer's condition anything is possible with the driver's side. Well, being in great shape is rather unlikely at this point.

donniekak: your suggestions are both reinforced, thank you.

Any danger of breaking a case casting or bearing if I have to hammer on it still in the transmission? Is the 3 jaw puller strategy as sound as hammering? From my understanding its seems a little safer, if not more effective.

Thanks again, will give it a shot.

 

[twicks69]

Well, the center diff and output shaft are junk, so just hit it accurately and you won't have a problem.

 

[markmakeitso]

Update on progress: Pulled the transmission last weekend, have been working on getting it apart since then. The output shaft finally came out with 8lb sledge persuasion. As far as I can tell it has some material buildup about an inch in from the VCC side splines that wouldn't all it to slip through the front output shaft easily.

Finally got the side gear and case out last night, after lots of effort. Eventually resorted to using a die grinder to cut down the side gear completely through at 2 points. Then chiseled slots down the front output shaft and "folded" the halves inward until the gear halves came free. In order to get the diff case out I had to break off those folded pieces and roughly repeat the process only lower down the shaft. Locking a round prybar in the case side holes and rocking eventually loosened it enough to slip free.

Will try to post some pictures of the carnage soon. Good times. Also need to track down a center diff to throw in to get back on the road.

Thanks for the advice everyone. Pulling the trans out was definitely necessary for solving this problem.