MY 1949 olds 76 Hydro-matic is leaking very badly from the front main seal( i Think) if i neet to swap it out what will bolt up to the 257 6 Cyl? are all the Hydro-matics from that era the same?

 

Why would you swap the transmission if all it needs is a seal?

 

I agree. If the leak is the only problem, carefully remove the transmission, replace the seal properly, and re-install it. It should provide years of good service. I've done the job before.

 

I guess Im just worried about messing with the trans. The service manual shows the tear down and i dont have any of the special tooling. is it easy to change the seal? I found a kit on eb** that has all the outer gaskets and seals for $70.

 

You don't need to disassemble the entire transmission to change the front seal. It's one of the easier jobs on the transmission. You don't really need any specialized tools to do the work except it would be best to have a transmission jack for the removal process unless you are REALLY A BIG BOY! The Hydramatic is heavy and it's no fun having it lying on your chest. You can get the jack on loan or buy one for about $100. If everything else is working properly you won't have to get "inside" the transmission case. Just be sure to mark everything as you take things apart so you can put it back the same way. Marks and photos really help. Don't force anything. The service manual should be a help. Read it well and understand things before you start. The gasket & seal kit should have what you need as long as it applies to your version. You can also buy the seal separately if you want. If you want to see a photo of it or buy it look here: http://www.rockauto.com/en/moreinfo....sn=365&jsn=365 ($15.61 + shipping) You will need to remove the old seal and install the new one. Some sort of seal tool will probably be needed for this or substitute something. Perimeter sealant may be needed. Follow the manual. Don't change the length of the rod going to the engine or you will change the shift points. If the transmission fluid has never been changed, it's probably time to do it. USE THE CORRECT FLUID! And be sure to drain the torus. I did all this many years ago on my '55 and all went well. Today it is still leak free. There aren't very many transmission mechanics today who are familiar with the old Hydramatics. Doing it yourself may be better than turning it over to some other inexperienced person.