Newbie from Miami

[marshall]

Hi all,

I have a 1966 1600 4 speed

I have have what seems to be transmission leak. I read in many places that transmission fluid is red in color and smells really bad. Mine doesn't smell and it seems to be pretty clear.

Anyways, after searching the forums an looking under the car, I figured that must be coming from the rear transmission seal where the drive shaft and the transmission meet. I figured the seal needed replacement.

I finally go the guts to remove the drive shaft after watching some youtube videos. That went pretty smooth, but then upon inspection of the rear of the transmission I noticed something weird. Not sure if its residue or if its like a crack or hole filler. What is that orange thing?

Anyone have an idea? Thanks for the help.

[drieseck]

Someone smarter than I might correct, but, I'd say the PO trade to seal the same leak with plastic goop/filler along the edge.

BTW, welcome, very nice car. Someone here will have the correct fix and procedure.

[marshall]

Hi drieseck, Thank you for your help.

Yeah, I guess what you are saying makes sense. My only doubt is wouldn't just replacing the Seal had fixed the issue. Or is it common in these cars to have to add the goop.

I am hesitant to remove it because I am scared of finding a bigger hole in the actual metal. Not having experience I also can't tell if the current seal is still working, or if it already time to replace it.

Or maybe they just added the goop because they didn't have a seal.Ahhhhhh . I wish I knew. What do you guys suggest?

[DAC21]

In addition to the seal there is a sleeve bushing surrounding that output shaft. I have read some older threads on 311s that a few folks were replacing the seal but it didn't take care of the gear oil leak. as the issue was a worn bushing. Unfortunately that bushing is no longer available. It would be fairly easy to reproduce by a machine shop but I guess the demand isn't there and or price prohibitive. That could well be an issue you are having. But no way to know without replacing the seal which if my car I would do.

Bushing is item 34 at the link.
https://www.carpartsmanual.com/datsun/s ... 1600-(r16)

[drieseck]

I likely have a shop that can do it for you if someone here can provide the specs.

[marshall]

Hi Dac21 and Drieseck.

Thanks for the input. Well I am going to start just trying to remove the goop and the seal right as I type. Hope that is all that it needs. Wish me luck. I am going to wing it.

[marshall]

Well I winged it and now I am 100% thats where the leak is coming from. Unfortunately my suspicions have been confirmed.

Its a crack. Any suggestions as to how to proceed? All suggestions are welcomed.

[marshall]

Anyone know where I can get a rear bell housing? (not even sure if that is what you call it.) Thanks for your help!

[Mackn367]

I’m guessing when the transmission was pulled by previous owner it might have fallen and chipped off that end. I’m surprised that was the only damage. You might be better off finding a whole new transmission housing and swap out all the internals. Unless you can live with the leak - bc a crack like that might have you chasing that leak for a while. And I’m not sure a legit repair would be worth the cost… go online and see if you can find just the transmission casing. Someone on this forum may even have extras laying around.

[marshall]

Hi Nick,

Yeah thats what I figured. Yeah thats what probably happened, and of course they did not mentioned it at the time of sale.

Anyways, I am guessing to replace the tail housing I also have to pull the transmission out including the engine?

[Gregs672000]

Well... that sucks. Replacing the rear case etc requires pulling the engine etc, hunting down a replacement case or trans, hoping it's good...

Given all that, I'd strongly consider redoing the previous "repair." You have little to lose really and it may work perfectly. Clean things really really well... no left over oil etc... brake cleaners do a good job, and if trans oil keeps coming out on ya you may need to either drain some or raise the rear of the car higher than the front. There are decent epoxy "cold weld" compounds such as Devcon and JB Weld that can be used (based on the color it looks like it may have been Devcon before?) that can be filed and sanded once set. I'd install the new seal, reclean again and replace the metal with the compound, making sure to have it up against the seal etc. to keep any oil from getting past the outside of the seal, then file and sand into the proper shape. I don't know how much stress or "impact" this area experiences, but IF the mating surfaces are clean these compounds are strong and can work. Alternatively, I've been surprisingly successful using aluminum welding rod and a propane torch to weld up aluminum stuff. The rod is available at Harbor Freight and there are YouTube videos on it. However, you're under a car with oil and undercoating and a torch... a bit scary and it may not be as easy. You also might try it if you decide to pull the engine and trans.

Worst case scenario is that it still leaks some and then you'd know you tried the "easy" approach and now have to move to a better fix. If it still weeps a little it may be something you decide to live with... my engine leaks a bit, oh well... car has seen 300k miles in the 38 years I've owned it, and it's never not leaked something!

[DAC21]

I’m guessing when the transmission was pulled by previous owner it might have fallen and chipped off that end. I’m surprised that was the only damage. You might be better off finding a whole new transmission housing and swap out all the internals. Unless you can live with the leak - bc a crack like that might have you chasing that leak for a while. And I’m not sure a legit repair would be worth the cost… go online and see if you can find just the transmission casing. Someone on this forum may even have extras laying around.

Yep, same issue I have with my car. The original owner back in the late 60's early 70's before my sister bought the car had the engine pulled for whatever reason. I only knew because many years later I noticed that the engine puller bracket that should have been on the back of the head was missing. There would be no reason to take it off for a clutch job, so I suspect some head work. After I bought the car from my sister I noticed a tranny leak, of course it was there when she owner it but she had moved out of the house and she sure didn't notice it Upon inspection I found the same chunk of the rear tail casing missing, though not as bad as the OP's. I have read here on 311s that when pulling / installing the engine / tranny put a cut up tennis ball on that location to prevent it slamming on the concrete unprotected. An anti fatigue mat would accomplish the same thing.

[marshall]

Thanks guys,

Yes, thanks for the suggestion, I think I will do the Devcon fix for now and refill the transmission fluid.

Does anyone know if this website is still in business: http://www.datsunroadster.com/default.htm

Thanks again for the help. Much appreciated.

[DAC21]

Thanks guys,

Yes, thanks for the suggestion, I think I will do the Devcon fix for now and refill the transmission fluid.

Does anyone know if this website is still in business: http://www.datsunroadster.com/default.htm

Thanks again for the help. Much appreciated.

Nope, shut down with no notice about three years back. Still a wealth of information. They are still sitting on possibly 7 figures of inventory as speculated by another Vendor.

[Mackn367]

Thanks guys,

Yes, thanks for the suggestion, I think I will do the Devcon fix for now and refill the transmission fluid.

Does anyone know if this website is still in business: http://www.datsunroadster.com/default.htm

Thanks again for the help. Much appreciated.

Yeah if it was me (today) I’d clean it up and try to fix it on my own starting from easiest job to hardest and stop where I feel comfortable (mentioned above are great ideas like cold welding/etc). A small leak in the rear seal is not a big deal. Keep an eye on it and fill up if/when needed. Bigger concern would be getting metal shavings in the transmission while doing the cleaning/fixing. So maybe if you plan to do anything have a vacuum constantly going so all debris goes to the vacuum and not inside the case.

Pulling the engine actually isn’t really that difficult but once you pull it you will then open up the rabbit hole of - “well I might as well fix/replace this while I’m here” and next thing you know you have a fully rebuilt motor and transmission haha.