have 1986 chev k10 auto trans leaks bad we replaced the seal it still leaks. what else could it be?


Asked by Jul 20, 2013 at 06:25 PM about the 1986 Chevrolet C/K 10

Question type: Maintenance & Repair

is it possible the seal didnt get put in right. after we replaced the seal we pulled tranny all the way out, pulled the converter out and it was leaking out the seal in the center part.is that normal

6 Answers

John Carson

I had a Ford Ranger that the gears went dry and froze because of a leaking Tranny. After SIX rebuilt replacements by the Ford dealer, and the identical problem, I traded it in for a F-150. Ford gave me a great deal, refunded my repair costs, and got top blue book for the Ranger. Loved my F-150. I was told the old transmissions are made of soft metal material, and the back drive shaft housing gets out of round. This prevents the new seals from seating and holding in oil. For some reason Ford refused to put in a new factory transmission. They said it was a newer model year and it would not bolt up?


sounds like you got a pretty good deal from ford. This leak is coming from the bell housing area. my mechanic says he thinks there might be a hairline crack on the pump cover. were not sure. at this point everything has been pulled back out. it mostly leaks when the truck is not running. not sure what to do next. thanks

John Carson

Go to a junk yard and get a used bell housing. Find the leak, make sure it is no internal, then swap. Good luck. Yes I loved my F-150. Sold it to my son-in-law who drove it many more years who than sold it to his son. He had it a few years until a DUI driver hit it, pushing it onto the southbound freight train tracks. It went from New Mexico to New Jersey over the next week.


ok since last post we pulled everything back out, replaced the main seal AGAIN we even pulled the trans. pump and replaced those seals. the O ring gaskets so on then we replaced the filter, pan gasket so on. put everything back together..and yes it f...... still leaks the only thing we havnt done is replace the torque converter. or could it be something else? please help!!!!!

John Carson

See my first answer above, the alum Ford trans housing I had over the years got out of round where the shaft hooks onto the drive shaft preventing new seals and rings from seating. Ford could not fix it, and refused to give me a new transmission. Is the leak from the rear of the transmission? That's where mine was. The soft material used in the "weight saving" transmissions are like the old Vega engines. Throw a-ways after 50K miles. It really is frustrating, and I have been there. My last trans blew 250 miles from home. I only had 4th gear and a steep mountain pass to climb in Sunday go home traffic through L. A.

Michael Blake

Check to see if there is a groove in the shaft (snout) on the torque converter from wear. It will look like a thin line around the snout where it contacts the seal. If there is one there, it will leak no matter how many times you replace the seal. You will have to sleeve it. Just a thin metal sleeve that goes over the snout of the torque converter. cheap and easy. or you could replace the converter. Make sure you put some oil on the seal before you put in the converter.

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