New (used) transmission, leaking.

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Gordy_

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I've been helping my dad with putting a new transmission in his '91 2500. We put a junkyard transmission in it. I think it might be leaking at the tranny cooler lines, but I'm struggling to get the ***** on it. There is however that pressed steel cap (not exactly sure what to call it) and the filler cap. It only leaks when we have the transmission in gear (I think anyway. We had the truck on jackstands to see if the transmission was working).

It was working, but for some reason the front wheels weren't spinning in 4wd (the driveshaft wat though).

Does anyone know what's going on with the 4x4 and what is leaking on the transmission? (I got those cooler lines kinda snug i think, but maybe they are still leaking). Thanks again for the help!
 

NickTransmissions

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Steel cap = governor cover. There's a square cut rubber seal on the inside of the cover that's prob dry-rotted and needs to be replaced.

Take (good quality!) pics of the leaks and post here if they're coming from other locations. I would have replaced the front seal, pan gasket, TV cable, filter as well (not saying you didnt, just mentioning).

You may have to lock the hubs for 4WD to work but could be wrong (im no 4x4 expert, haha).

Lastly, do a pressure test to make sure you have both acceptable base line pressure at min TV as well as acceptable line pressure rise (ie at full TV).
 

Erik the Awful

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Make sure the TV cable is seating well. You have to install the grommet in the transmission before putting the TV cable into it. If you try to cram the TV cable in the hole with the grommet already on it, your TV cable won't work right and you'll leak transmission fluid.

Also check the dipstick seal. They're almost always swollen and leaky.
 

Gordy_

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Ok, so maybe it's not the cooler lines then. I used the original line as it was still functional and it just dropped in with no resistance. Maybe it's leaking there cuz it has no seal? I also didn't replace the seal for the fill neck. I did do the filter and gasket on it and put new fluid in.
 

Gordy_

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I got my issue solved. My dumb @$$ didn't realize I needed to take the brass fittings for the cooler lines off the old transmission, so the lines had nothing to seal against. It seemed to work. It pulled out of the garage and back in, so it's better than it was with the old transmission.
 

Erik the Awful

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The brass fittings are supposed to stay in the transmission. Did the junkyard sell you a transmission with the fittings removed? That's worrisome.
 

Gordy_

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The brass fittings are supposed to stay in the transmission. Did the junkyard sell you a transmission with the fittings removed? That's worrisome.
Yeah, there were no fittings on it. My guess is they just cut the transmission free and pulled the fittings rather than pull the lines out of the fittings. The transmission seems to work properly. We'll be back over there soon to button it up and take it out for a test drive.
 

Gordy_

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Came back to this leak. I think it might be the kickdown cable. Would that leak that much?
 

Gordy_

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Sorry, picture didn't seem to load in the first post.
 

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Gordy_

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I'm 90% sure that was my issue. There was no grommet. I snagged the one off the old transmission and that should work good enough for now.
 
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