Help needed AOD reassembly
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Help needed AOD reassembly
I am hoping that there is a transmission tech or two on the site who can help me. I am in the middle of reassembling my 1989 truck AOD. I am trying to reassemble the direct clutch assembly but I am unable to reinstall the snap ring that holds the output shaft gear into the back of the direct drum. I have disassembled, cleaned, and checked all parts numerous times, but the gear mounted on the output shaft stays about 1/1000th of an inch too far out from seating to permit the snap ring to go into its groove. Is there some trick I am missing? I don't recall it being overly difficult to take it apart.
I have the snap ring in the freezer right now, hoping it will shrink enough to fit into the groove.
Any advice will be greatly appreciated.
I have the snap ring in the freezer right now, hoping it will shrink enough to fit into the groove.
Any advice will be greatly appreciated.
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Anybody?
The freezer trick didn't work, so now the direct drum is in my oven heating to 200 degrees while the snap ring and output shaft assembly are in my freezer being chilled to sub -5 Fahrenheit temperatures. Hopefully that will fix this problem and the thermal shock won't damage anything on reassembly.
The freezer trick didn't work, so now the direct drum is in my oven heating to 200 degrees while the snap ring and output shaft assembly are in my freezer being chilled to sub -5 Fahrenheit temperatures. Hopefully that will fix this problem and the thermal shock won't damage anything on reassembly.
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Thanks for responding. I apologize. I realize my description are vague and pictures are always best in these sorts of situations.
Here is a picture of the parts I am talking about assembled with the snap ring as far into position as it will go. It fits into the drum, but won't fit into the groove for it machined into the side of the drum:
Here is a close up of the groove where the snap ring is supposed to go, but won't fit into. If you look close you can see that the "gear" or hub looks just about flush to the edges of the grove. However, the ring still won't go into the groove:
The snap ring will go into its groove easily with the "gear" or hub not installed, so it isn't a situation where I am using the wrong snap ring. These are all the parts that were in the transmission when I disassembled it, so I know they used to fit together. There is no interference between the direct clutch pack and the "gear" or hub.
Any suggestions or input is greatly appreciated. I don't want to damage something by forcing the snap ring into the groove.
Here is a picture of the parts I am talking about assembled with the snap ring as far into position as it will go. It fits into the drum, but won't fit into the groove for it machined into the side of the drum:
Here is a close up of the groove where the snap ring is supposed to go, but won't fit into. If you look close you can see that the "gear" or hub looks just about flush to the edges of the grove. However, the ring still won't go into the groove:
The snap ring will go into its groove easily with the "gear" or hub not installed, so it isn't a situation where I am using the wrong snap ring. These are all the parts that were in the transmission when I disassembled it, so I know they used to fit together. There is no interference between the direct clutch pack and the "gear" or hub.
Any suggestions or input is greatly appreciated. I don't want to damage something by forcing the snap ring into the groove.
Transmission Rebuilder
Joined: Jul 2008
Posts: 1,569
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From: North Georgia
Gotcha, look real close at all of your snap rings, I think the one that goes there is thinner than the others that are that size. Sometimes you can see the witness marks on the snap ring from the lugs on the gear.
The direct drum is the small drum that has the clutch plates in it, and it fits inside that part the you are referring to as the direct drum, I call it the rear ring gear.
The direct drum is the small drum that has the clutch plates in it, and it fits inside that part the you are referring to as the direct drum, I call it the rear ring gear.
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Thanks. I will double check, but there was only one snap ring that was the right diameter. The diameter of all the other snap rings was either clearly too large or clearly too small.
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Transmission Rebuilder
Joined: Jul 2008
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From: North Georgia
I will be at the shop tomorrow and I know I have a few of those laying around. I can give you the dimensions of it if you don't figure it out by then. I think that one has a big gap between the ends if my memory is correct.
In your picture it looks like the hub is sitting all the way down.
In your picture it looks like the hub is sitting all the way down.
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Transmission Rebuilder
Joined: Jul 2008
Posts: 1,569
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From: North Georgia
See the witness mark or wear pattern on the snap ring ( the light gray line on the inside ) it doesn't match the lugs on the hub. The snap ring should have a wear pattern like teeth on the outside of the ring.
Thread Starter
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Mountain Pass
Joined: Mar 2007
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Thanks for your help. I agree that the hub is sitting all the way at the bottom of its bore. If you get a chance to send me the dimensions of one of these snap rings, I would greatly appreciate it.
I just double checked- there are no other snap rings that are anywhere close to the correct diameter to fit in the ring gear. I am heating the ring gear up to 360 degrees this time instead of 200 degrees and cooling the snap ring and output shaft assembly to -5 degrees. Hopefully that will get me the clearance I need. In the meantime I will sort through the pile of parts again and see if there is a snap ring somewhere I am missing.
I just double checked- there are no other snap rings that are anywhere close to the correct diameter to fit in the ring gear. I am heating the ring gear up to 360 degrees this time instead of 200 degrees and cooling the snap ring and output shaft assembly to -5 degrees. Hopefully that will get me the clearance I need. In the meantime I will sort through the pile of parts again and see if there is a snap ring somewhere I am missing.
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Well, the heating and cooling trick didn't work the second time either. Now my kitchen smells like transmission fluid. Yum. I am probably going to take this assembly out to a transmission shop tomorrow and see if they have any ideas or any thinner snap rings that will work.
Thread Starter
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Mountain Pass
Joined: Mar 2007
Posts: 243
Likes: 1
Thanks for the effort. I took my pile of parts to two different transmission shops. The first couldn't help me, but the second (a small independent outfit that has been in business at the same spot for years) looked at it and told me it was the wrong snap ring. I agreed, but I am 99.5% certain that is the snap ring that came out when I disassembled. The shop told me that there is another snap ring in the forward clutch that is almost the same size but is thicker. That may be, but I haven't disassembled the forward clutch yet. My only conclusion is that someone was in the transmission before me and forced the wrong snap ring into the direct ring gear.
Anyway, the second shop gave me the right snap ring for free, so my direct clutch is reassembled. Yay! Now I can progress on to disassembling and reassembling the rest of the transmission. Hooray for independent shops that still take the time to treat their customers right!
Thanks for the input. If I have any more questions I will be sure to come here first.
Anyway, the second shop gave me the right snap ring for free, so my direct clutch is reassembled. Yay! Now I can progress on to disassembling and reassembling the rest of the transmission. Hooray for independent shops that still take the time to treat their customers right!
Thanks for the input. If I have any more questions I will be sure to come here first.