ATF leak

[goat_72]

Today I took my 72 F100 with a FE 390 C6 Auto to Jiffy Lube for an oil change. I have seen since buying the vehicle in the fall of 2017 that there has been a small leak, mostly ATF. On checking the fluids, ATF was definitely low.

We tracked down the leak to two places, one the driver side where the linkage to the shifter is and then more prominent leak being on the connector between main shaft and transmission. The chap at Jiffy, suggested it is a rubber seal of sorts and fairly easy fix, but requires to take the shaft out.

Pic attached of the part in question. Considering this is dismantling of the shaft from the transmission, I suspect it's a good opportunity to do take care of others things perhaps on the other side of by the differential.

Subject to keep an eye on ATF levels, how urgently / or worried should I be in prioritizing this fix. I am toying with doing it myself, or taking it to a shop. As you can probably tell, this is not my primary skill set. None the less willing to give it go.

Last stupid question, what is the correct terminology for these transmission anatomies ??

Thanks.
GOAT_72

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[Bill Ramsey]

output shaft seal. easy to do if you know how and have the tools.

my bigger concern is asking the guy at jiffy lube for advise. they were not thinking of oil changes when they named that place.

[Jacksdad]

my bigger concern is asking the guy at jiffy lube for advise. they were not thinking of oil changes when they named that place.

Exactly right. They don't make any money giving advice, and a seal change can easily turn into a transmission rebuild once it's up on a lift and torn down. Ask me how I know...

[DuckRyder]

It is a long bed with a 2pc driveshaft right?

Speedometer gear adapter looks suspect too, I would clean it all off and keep an eye on it...

[goat_72]

Hi

@jacksdad - the dude at Jiffy wasn't suggesting they would fix it just to be clear, but helped track down the leak itself. I am debating wether this is something I do myself or get someone (i trust) to do it.

@duckryder - no this is a swb. as for the speedometer gear adaptor, are you referring to the two cables rubbing or the apparent degradation of the horizontal cable - aka I presume this is the speedo cable?

I suspect you guys telling me to get this into a reputable transmission / mechanic shop?

[DuckRyder]

It should not be hard if you have some mechanical skill and we can help you too.

The speedometer cable is the one going into the transmission, it screws on to an adapter that is held in by the bolt below it in the retainer. There is a seal (an O ring) on it.

I was under the impression that short beds had a slip yoke in the transmission tail shaft but that looks like a bolt on yoke on the back of the trans (is there a huge nut in the center of it)

In anycase, If you do change the tail seal, you will probably want to have a seal saver onhand (it is a sleeve that will go over the surface of the yoke and give a smooth surface for the seal to ride on if there are groves worn into the yoke).