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How does transmission engage the differential

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How does transmission engage the differential

 
Old 02-19-2019, 02:36 PM
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SRaouf
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Default How does transmission engage the differential

I know this is probably a really stupid question and highlights my lack of experience with transaxles in general and automatic transmissions in particular, but how does the drive shaft connect with the differential? I recently removed the joint flanges and the housings to replace the sealing and O rings and the differential just came out the back (I have the cover off) as the only thing holding it in were the taper bearings into the flange housings. Once refitted it just rotates freely without being connected to anything. The transaxle/transmission/torque tube are out of the car if it makes any difference.
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Old 02-19-2019, 03:00 PM
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Speedtoys
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How does the drive shaft, or the transmission output?

There is a shaft from the clutch/flexplate to the transmission..and the transmission has an output pinion, that engages the differential. (#5)

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Old 02-19-2019, 04:03 PM
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SRaouf
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My question is how does the transmission engage with the differential, as they did not connect when I refitted the differential (or did I refit incorrectly?)
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Old 02-19-2019, 04:11 PM
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Gonna guess you put it back wrong.

You should be able to see the pinion gear on the end of the shaft by looking in from the back.
The ring gear on the diff needs to engage that properly.

Setting that correctly is very important, if you want the gears not to self-destruct.

The difference between 'correct' and 'will destroy the diff in a short time' isn't much.

There are lots of jobs I will do on a car, setting up a diff is not one of them.
I would suggest that you find someone who knows what they are doing to put it back together.
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Old 02-19-2019, 04:16 PM
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The little gear on the end of the shaft (in Speedtoy's picture) turns the big gear (in Speedtoy's picture). The big gear comes from inside the transmission and the big gear is on the differential. There's no actual physical "connection" to the two, the teeth are just very close to each other.
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Old 02-19-2019, 04:24 PM
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I didnt take the differential apart it all just came out as one unit which I put back in the same way it came out, held in by the roller bearings on each side. So did it need to be inserted in a certain way and aligned with the shaft or simply inserted with the roller bearings seated properly and using the same shims? at the moment the differential rotates freely on the roller bearings
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Old 02-19-2019, 04:53 PM
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It needs to be put back exactly the same way it was before.

Same shims in same places. Same everything.

If it fell out and stuff got mixed up, you will need to have the gear engagement (Lash?) set properly.

In any case, I would suggest having it at least checked over by someone who knows what they are looking at.

As I noted above, this is beyond my skill & experience. I can't tell you what to look for or what it looks like.
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Old 02-19-2019, 05:33 PM
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Can you provide photos of what you took out?
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Old 02-19-2019, 05:53 PM
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Originally Posted by SRaouf View Post
I didnt take the differential apart it all just came out as one unit which I put back in the same way it came out, held in by the roller bearings on each side. So did it need to be inserted in a certain way and aligned with the shaft or simply inserted with the roller bearings seated properly and using the same shims? at the moment the differential rotates freely on the roller bearings
If you put it back in the same way it came out (ring gear on the driver's side of the pinion) with the aluminum side pieces (hold the bearing races) and shims in the same position, you are fine.

Install the cover and fill it with gear oil.
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Old 02-20-2019, 12:40 AM
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What makes you say it isn't connected to anything?

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Old 02-20-2019, 12:51 AM
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SRaouf, please look at the photos in my thread to see if this clarifies anything. If nothing else, it will help us understand specifically what you are seeing:
The photos you need are in post #88:

https://rennlist.com/forums/928-foru...n-wyait-6.html


Good Luck! It sounds like these guys have told you what you already need to know. When you removed the side plates, that released the differential assembly.
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Old 02-20-2019, 01:08 AM
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Originally Posted by fiatrn View Post
What makes you say it isn't connected to anything?
I think in this comtext, the OP is taking about a direct physical connection that would keep the differential inside the housing, instead of just falling out.

Very close to the pinion isn't a direct connection....
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Old 02-20-2019, 09:09 AM
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Originally Posted by GregBBRD View Post
I think in this comtext, the OP is taking about a direct physical connection that would keep the differential inside the housing, instead of just falling out.

Very close to the pinion isn't a direct connection....
Greg is exactly right thats what I meant. I had another good look in the cold light of day and it all makes sense now. I have been referring to the complete assembly (ring gear, carrier disk and housing photo attached) and can see that the ring gear is indeed meshed with the pinion shaft behind it. I suppose Im overly paranoid as getting the transmission off in a sloping driveway was a horrible job and Im not look forward to doing that again soon. Thanks everyone for your input

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Old 02-20-2019, 12:54 PM
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...so that ring gear is only retained in the housing when the stub axles are inserted?
no "retaining brackets" like this 8.8?
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Old 02-20-2019, 01:43 PM
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No, the stub axles have nothing to do with it.
The differential assembly is wholly retained by the side plate bearing cups. Shims between the side plates and the differential casing both set the preload for the bearings and set the distance of the ring gear from the pinion gear.

That 8.8ö rear end looks like the one in my Explorer. The differential assembly is held in by those two bearing caps.
I recently had the axle shafts out of mine to replace the outer bearings and seals.
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