How does transmission engage the differential
#1
Racer
Thread Starter
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.
#2
Rennlist Member
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)
There is a shaft from the clutch/flexplate to the transmission..and the transmission has an output pinion, that engages the differential. (#5)
#3
Racer
Thread Starter
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?)
#4
Nordschleife Master
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.
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.
#5
Rennlist
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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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greg brown
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
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greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
#6
Racer
Thread Starter
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
#7
Nordschleife Master
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.
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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#9
Rennlist
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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
Install the cover and fill it with gear oil.
#11
Rennlist Member
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.
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.
#12
Rennlist
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#13
Racer
Thread Starter
#15
Rennlist Member
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 8.8” 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.
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 8.8” 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.