Hydra transmission leaks after drain & flush??

[mbflemingkf]

Anyone hear of major leaks on hydramatic after bottom pan dropped, cleaned, and filter thoroughly cleaned and then refilled with fresh trans fluid??  My mechanic is saying the cleaning and fresh fluid increased the pressure causing the leaks.  Appears to be coming from the seal around the main transmission shaft that mates with the engine.

He's telling me the transmission needs to come out for these repairs.  Wait a minute...we just had it out and detached from the engine!!!???

 

[boatingbill]

Why would they have to remove the transmission to clean the screen and flush the fluid?

[shadetree77]

I can't speak for my Hydramatic (yet) but the same thing happened to me on my Dynaflow. I dropped the pan and cleaned everything. Shortly after, I developed a HUGE leak in the same spot that you describe. Had to take the trans. out and replace that seal.

[joefrazer]

The front seal on a hydramatic is only accessible from inside the unit so it has to be torn down to replace it. About the leak, I had the same thing happen and it is due to the increased pressure compliments of the filter screen being clean. I didn't believe the tech at first but after consulting a few old-time transmission guys, they confirmed it.

So, you'll have some serious cash spent to replace a five dollar seal.

[custom]

I work in the Ag Industry. When a seal leaks from age, (not torn) we use a transmission additive to " soften" the seal. It doesn't always work, but it is worth a try.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/A-Trans-Fluid-Additive-Blue-Devil-Transmission-Sealer-16-fl-oz/_/R-NCB00236_0422914560

custom

[mbflemingkf]

Thanks, yes, he said he did add this product but said it takes 75-100 miles to work.  I haven't been this far so maybe it will work.  Right now the bottom cover is dropped to see up in there and waiting for the trans guy to come by and give his opinion.  May be best at this point to pull the trans and do the front seal and let the "mechanic in a bottle" work on the other seals/gaskets?

[mbflemingkf]

Why would they have to remove the transmission to clean the screen and flush the fluid?

Had the trans and engine out to replace the engine due to block being bad.  Since the trans was out, he did the flush and filter clean.  He also found some metal shavings in the bottom pan and clogged in the filter.  He said the trans would have to be rebuilt!  Oh my...just dropped $4500 in the engine.  Wondering if I should go with a rebuild too in addition to the seal??  Amyone had a hydramatic transmission rebuilt lately...what should that cost??   

[mbflemingkf]

The front seal on a hydramatic is only accessible from inside the unit so it has to be torn down to replace it. About the leak, I had the same thing happen and it is due to the increased pressure compliments of the filter screen being clean. I didn't believe the tech at first but after consulting a few old-time transmission guys, they confirmed it.

So, you'll have some serious cash spent to replace a five dollar seal.

...drat, Jim, what range of $$ do you think I'm looking at.  I remember you telling me before it it wasn't leaking and shifting OK to leave it alone and just add fluid as needed.  I followed your advice then, just seemed like the right this time while the trans was waiting to go back into the car.  Obviously now wish I';d have left well enough alone!!


 

[BigDave LM6174]

I had my hydramatic rebuilt top to bottom when it completely failed.  Old Trans shop rebuilt it in Los Angeles for 2,200 and that was using a couple spare donor parts they had from other ones laying around.  Expect 2-3k for complete rebuild

[joefrazer]

Hydramatics are fussy units...unless they fail, it's usually best to keep the fluid full and leave them alone. A friend works in the business and recommends doing nothing to a unit that has age or miles on it. I've followed his advice and so far, my 53 has given me no trouble. Of course, now that I've said something...

[MilesP]

Mike when I had my 55 engine rebuilt also had to do my tray Amoco charged me 2200 but both units now work except for a exist leak which causes a tick plan to have a second gasket put in next year .

[mbflemingkf]

Thanks, Miles, when you reattached your exhaust, did they use one of the round compressable donut gaskets in addition to the flat gasket between the exhaust pipe and the exhaust manifold?  Typically, both are needed.  Do you have one of the round donut gaskets?

[retired wrench]

  Any  time you unbolt the converter from the engine it drops down a little. With a flexable seal this doesn't mean anything. With an old stiff seal damage can be done. Whenever you unhook one replace the seal.

[mbflemingkf]

retired wrench...so this is the front oil pump seal(that the shaft goes thru), right?  Any idea how much work or $$ might be involved?  I'm trying to weigh just getting this seal replaced vs. having the whole trans rebuilt.  I guess I'm just not sure this will solve all the potential leaking problems....then again, no one has a crystal ball on this stuff, I know!  I'd sure like to wait a bit before having to rebuild the trans after the large expense on the engine. 

[MilesP]

Mike I am pretty sure my mechanic did not have the disks you mentioned any chance you know where I could but them ?