The Ford Barn

Ken Henry · 08-05-2022, 11:31 AM

So I just finished filling my freshly rebuilt overdrive transmission with Redline MT90 and found a leak between the plate that the solenoid mounts to and the overdrive unit. All the bolts seem tight and the fluid is coming out at the location marked by the yellow arrow.

Is there anything that can cause a leak at that location that could possibly be addressed without pulling the transmission again? For example a missing seal for the solenoid or something like that? There is no fluid accumulating on the flange for the solenoid...

Thought I should check with the experts before tackling the transmission pull.

Thanks! Ken

OD_leak by kenhenry_06268, on Flickr

Don T · 08-05-2022, 05:23 PM

There is a seal (7693) between the solenoid and the transmission adapter which could be the problem and can be replaced without pulling the transmission. I had a problem with the gasket (7661) not quite fitting correctly which would have caused a leak between the tailpiece and the adapter. I made my own up out of gasket material. Unfortunately this requires pulling the transmission and all the fun in removing the cross-member. Hope this helps.

Ken Henry · 08-08-2022, 11:05 AM

Thanks Don, I couldn't imagine any way the solenoid seal could leak without fluid accumulating on the lower mounting bolt, so I pulled the transmission. I wonder I have the same issue with gasket used on the tailpiece. I'll touch base with the rebuilder but it would be nice to avoid the hassle and risk of shipping the transmission again. Can you provide a little more detail about the issue with the fit of the 7661 gasket? I have some gasket material but it seems thicker than typical transmission gaskets. Do you happen to recall what thickness you used? Thanks!! Ken

Don T · 08-10-2022, 10:01 PM

The gasket that I got was totally wrong; it was simpler to make a new one than reorder. I doubt of the thickness was important. If you have had someone rebuild the trans the first thing you should do is call him; tell him what the issue is, work with him on it. No legitimate rebuilder wants to put out bad product, it could be the gasket you suspect and maybe a replacement could be made by yourself without the shipping hassle/costs. If you touch that thing without a conversation with the rebuilder you are shooting yourself in the foot.

Ken Henry · 08-11-2022, 09:19 AM

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Sounds prudent Don, thanks, just waiting on the call back. I have my old 49/50 transmission reinstalled. It has a worn third gear sychro but otherwise will work fine while I wait. Ken

08-05-2022, 11:31 AM	#1
Ken Henry Senior Member Join Date: Jul 2010 Location: Rochester, NY Posts: 266	51 OD transmission leak source? So I just finished filling my freshly rebuilt overdrive transmission with Redline MT90 and found a leak between the plate that the solenoid mounts to and the overdrive unit. All the bolts seem tight and the fluid is coming out at the location marked by the yellow arrow. Is there anything that can cause a leak at that location that could possibly be addressed without pulling the transmission again? For example a missing seal for the solenoid or something like that? There is no fluid accumulating on the flange for the solenoid... Thought I should check with the experts before tackling the transmission pull. Thanks! Ken OD_leak by kenhenry_06268, on Flickr

08-05-2022, 05:23 PM	#2
Don T Member Join Date: Mar 2017 Location: Alberta Canada Posts: 93	Re: 51 OD transmission leak source? There is a seal (7693) between the solenoid and the transmission adapter which could be the problem and can be replaced without pulling the transmission. I had a problem with the gasket (7661) not quite fitting correctly which would have caused a leak between the tailpiece and the adapter. I made my own up out of gasket material. Unfortunately this requires pulling the transmission and all the fun in removing the cross-member. Hope this helps.

08-08-2022, 11:05 AM	#3
Ken Henry Senior Member Join Date: Jul 2010 Location: Rochester, NY Posts: 266	Re: 51 OD transmission leak source? Thanks Don, I couldn't imagine any way the solenoid seal could leak without fluid accumulating on the lower mounting bolt, so I pulled the transmission. I wonder I have the same issue with gasket used on the tailpiece. I'll touch base with the rebuilder but it would be nice to avoid the hassle and risk of shipping the transmission again. Can you provide a little more detail about the issue with the fit of the 7661 gasket? I have some gasket material but it seems thicker than typical transmission gaskets. Do you happen to recall what thickness you used? Thanks!! Ken

08-10-2022, 10:01 PM	#4
Don T Member Join Date: Mar 2017 Location: Alberta Canada Posts: 93	Re: 51 OD transmission leak source? The gasket that I got was totally wrong; it was simpler to make a new one than reorder. I doubt of the thickness was important. If you have had someone rebuild the trans the first thing you should do is call him; tell him what the issue is, work with him on it. No legitimate rebuilder wants to put out bad product, it could be the gasket you suspect and maybe a replacement could be made by yourself without the shipping hassle/costs. If you touch that thing without a conversation with the rebuilder you are shooting yourself in the foot.

08-11-2022, 09:19 AM	#5
Ken Henry Senior Member Join Date: Jul 2010 Location: Rochester, NY Posts: 266	Re: 51 OD transmission leak source? Sponsored Links (Register now to hide all advertisements) Sounds prudent Don, thanks, just waiting on the call back. I have my old 49/50 transmission reinstalled. It has a worn third gear sychro but otherwise will work fine while I wait. Ken