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1991 Subaru Loyale FWD 3AT Front Differential Repair or Replace Build


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Just started to pull the 3AT out to repair the front differential which is hammered. The transmission is fine just the differential is the problem. I already have a 5 speed manual FWD transmission with clutch, flywheel ready to go in if the 3 AT is unrepairable.Photos and updates to follow. 

Edited by Moto7man
Grammer
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  • 2 weeks later...

Removed torque converter, I had already drained ATF from transmission, the front differential was dry. Looks like the pinion bearing disintegrated, then the pinion disintegrated and took a chip out of the ring gear. I marked the component positions with a marker.hpzOQCQ.jpgMkdkRv8.jpg

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I know I have to remove the next section to get access to the pinion nut. I have already removed the external case bolts with the double washers.Do I move the governor, the speedo gear and the oil pump drive shaft,the turbine output shaft by removing the oil pump shaft bushing,the spring pin,the snap ring,the speedometer drive gear,the other snap ring? Then will the 2nd section of the case split away?

nGQxmpi.jpg

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I had one front diff run dry, leaked out the axle stub seals.

The dead bearings wrecked the inside of the front case section.

The oil pump shaft just slides out.

The dissasembly starts at the rear end.

The transmission parts are likely still as good as they were when it was running.   The diff is seperate,  uses gear lube.  The seals between the diff and the transmission sections are probablyruined also.

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Everything you described is standard mode of operation for the 3AT! We had one in the family lock up when the pinion shaft tried to insert itself into the diff centre when the pinion bearing imploded/exploded itself - due to a lack of oil! 

All the best with the rebuild... 

Cheers 

Bennie

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I pulled the differential off yesterday. It was fairly straight forward. I removed the governor assembly, the sun disks,the bearings,drive gears, everything pulled out of the case without a problem, then I split the differential case from the rear of the transmission. Now for the bad news, the reverse side of the differential case wasn’t in bad shape, but some bearings from the destroyed pinion bearing had damaged the upper shaft gear and housing. Also, the the entire back side of the differential housing was full of fine metal debris. Also, due to lack of lubrication, the governor was begging to apple core a little bit

 The transmission section was like new and damage and debris free. The transmission has always run perfect and it is looks new inside. I bought a 5MT five years ago with a flywheel and clutch kit and shifter, so I am going to install go the mt route. I need a mt manual transmission crossmember with the longer bolts if anyone has one. 
 

If anyone needs this 3AT,just pm me, it works fine, it just needs a differential.

 

 

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  • 1 month later...

IbXyWEI.jpgbmDu0fs.jpgIs the rear electrical connector for the reverse light?Is the other connector for the dash or clutch interrupter?


 

The oring and seal behind the bearing retainer looks good, no leaks anywhere,would it be a good idea to replace the oring and seal anyway? 

wrbMVMx.jpg

 

 

Edited by Moto7man
Specify question in greater detail.
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On your last picture-  If you remove the bearing holder, you will have to re set the bearing pre load / pinion & ring gear alignment.

Maybe if you carefully, mark the position, and count turns while removing you could get it back where it was.    I have not tried this.  I have read the FSM directions for assembly, it doesn't seem trivial / fun to do right.

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Those are almost never preventatively replaced.  They’re relatively easy to do in the car. Pull axle and replace. I wouldn’t do it unless the history and/or condition of the trans and seals wowed me. I might make the decision based on condition history storage.

But they do leak occasionally, that’s a very old trans, and are very simple to do right now

Mark exact location and count turns if you do. It needs installed the exact same location and depth to orient the front diff guts.
 

 

Edited by idosubaru
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