1963 Bonneville Transmission Question

[Trixster22]

Need some help. Noticed a very large puddle of transmission fluid under my car. It has the original engine, transmission and rear end. The puddle was rather large. The last time I drove it the transmission was fine. In looking under the car, it is leaking where the rear of the transmission meets the drive shaft. As I was looking at it, I could see the fluid dripping. Any advice/help would be appreciated. I assume it's tranny tail shaft seal, but I wanted to see what you guys think. What do you think it is? The puddle is large. Is this a fairly straightforward repair? Is it an expensive fix? Any help you can give would be greatly appreciated. Thanks!

 

[melsg5]

have to go on what you are seeing. Typically the seal can be replaced without removing the transmission and should not be a lengthy repair.

 

[cammerjeff]

A leak out of the rear seal after the car has been sitting for awhile is usually caused by the fluid draining back out of the torque converter when the car sits. Check the fluid level with the dip stick. It will probably be high.
You can replace the rear seal easy enough, but it won't solve the problem. There is in internal seal leaking. But it does not have to be changed, I had a couple of original low mileage cars with this issue, I would just drain 2 qts of fluid out if it was going to sit for more than a week or so. And refill it when I went to drive it. Kinda a PITA but a lot cheaper than a trans rebuild. If the trans works normally other than this issue it is something to think about. That and putting a thin wide drip pan under it when it sits.

 

[Trixster22]

A leak out of the rear seal after the car has been sitting for awhile is usually caused by the fluid draining back out of the torque converter when the car sits. Check the fluid level with the dip stick. It will probably be high.
You can replace the rear seal easy enough, but it won't solve the problem. There is in internal seal leaking. But it does not have to be changed, I had a couple of original low mileage cars with this issue, I would just drain 2 qts of fluid out if it was going to sit for more than a week or so. And refill it when I went to drive it. Kinda a PITA but a lot cheaper than a trans rebuild. If the trans works normally other than this issue it is something to think about. That and putting a thin wide drip pan under it when it sits.

Thanks, cammerjeff. I appreciate your help. But, the car hadn't been sitting for a while. I drove it the day before, and it was fine. It's always had a slight leak, but it was nothing like what I found the other day. It had to have poured out of the seal.

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[cammerjeff]

If it has been recently driven then plan on replacing the rear seal, also check the driveshaft yoke for excessive wear as that is what the seal uses to seal.

Also check how much play you have in the drive shaft, side to side and up and down when it is inserted into the transmission, you could have a bad transmission output shaft bushing that is bad allowing the output shaft to move that will wipe out any seal put in. I have only had that bushing go on 1 car. You could not keep enough fluid in it when that happened. I tried to limp it home but no luck had to be towed.

Good luck, tell us what you find please

 

[Trixster22]

If it has been recently driven then plan on replacing the rear seal, also check the driveshaft yoke for excessive wear as that is what the seal uses to seal.

Also check how much play you have in the drive shaft, side to side and up and down when it is inserted into the transmission, you could have a bad transmission output shaft bushing that is bad allowing the output shaft to move that will wipe out any seal put in. I have only had that bushing go on 1 car. You could not keep enough fluid in it when that happened. I tried to limp it home but no luck had to be towed.

Good luck, tell us what you find please

Hey, Cammerjeff, I replaced the rear seal. Gave the drive shaft a good going over, and all is good. Got it all back together this morning. Test drove it, and no leaks.

Thanks for your insight and help. I really appreciate it!