I HATE Transmissions!

[Palf70Step]

Seems the nightmare of transmission leaks are not going to end on the 83. I went out to the shop last night and what do my wondering eyes see.....tranny fluid on the floor, AGAIN!.

Got underneath and found it leaking from the rear seal/yoke. I guess from sitting 5 years the rear seal was dried out (at least I Hope). I didn't notice any rough spots on the yoke from the 83, but I'll check that before I hook it back up. Least I have another good yoke if I need it.

It sure seems like I am not supposed to drive this 83 much. On well whining is done. Time to pick up a seal and change that out.

[makman1297]

Mine seems to leak when i dont drive it, guess its trying to tell me something.

[STOCKISH]

Its hard for me to see in the pic but it looks like the yoke is wet by the
u-joint and its dry around where the seal meets the yoke? If thats the case, (since it looks like the trans is clean enough to have been rebuilt) there is a seal internal to the tailshaft housing and if it was not installed it will leak through the tiny hole in the center of the yoke. If thats not whats going on, sorry for the rambling, just thought I'd throw that out there.

[old Rusty C10]

i dunno , Bill , sometimes these trucks just seem to find one thing after another to aggravate the owner

[lilpoindexter]

Usually the Automatics are the problematic trannies...that's why I stick to manuals...but the older I get, the more I get stuck in traffic, the more I find myself thinking about an automatic.

[Palf70Step]

Originally Posted by 1972SuperCheyenne

Its hard for me to see in the pic but it looks like the yoke is wet by the
u-joint and its dry around where the seal meets the yoke? If thats the case, (since it looks like the trans is clean enough to have been rebuilt) there is a seal internal to the tailshaft housing and if it was not installed it will leak through the tiny hole in the center of the yoke. If thats not whats going on, sorry for the rambling, just thought I'd throw that out there.

That is what I thought too. I did not know about the inner seal thing for the yoke. I guess I'll have to look into this further.

[STOCKISH]

There are two types of yokes that can be on these trucks. One has a small hole in the center of it (longways) and one is totally sealed. If yours has the hole in it you have to have the seal inside the tailhousing. Its a cylindrical seal.

[Palf70Step]

Originally Posted by 1972SuperCheyenne

There are two types of yokes that can be on these trucks. One has a small hole in the center of it (longways) and one is totally sealed. If yours has the hole in it you have to have the seal inside the tailhousing. Its a cylindrical seal.

I'll have to look at my other yoke to see if it is the hole kind or not. Tranny was originally in another vehicle, so maybe it needs the other type of yoke. I'll check out the yokes.

Thanks a whole bunch for the info!

[westie 666]

Had the same issue with my trans leaking when parked up for over two weeks, I removed the yoke and cleaned it up and put a dab of silicone in the small hole, has never leaked since.

[Palf70Step]

That was the problem, a hole in the yoke. I have the other yoke that came with the tranny (no hole) off and ready to install.

However, the U-joints on the drive shaft have no clips and the U-joints are not coming out of the shaft. My vice even cracked trying to press them out.

It looks like some plastic type stuff was put in the little holes to fill the inside grove instead of clips. Any of you folks ever run across that issue or design. I am guessing these are the original U-joints from the factory in 83.

[78 Chevyrado]

I hate trannies too, but I seem to like my TH400. its the ONLY auto trans in any car I've ever had I havent broken yet. and i drive hard and get pissed if the vehicle can't keep up.

And I've noticed, I drive HARD and this auto trans is also in the heaviest vehicle ive ever owned too.

[Mattman2010]

Originally Posted by Palf70Step

That was the problem, a hole in the yoke. I have the other yoke that came with the tranny (no hole) off and ready to install.

However, the U-joints on the drive shaft have no clips and the U-joints are not coming out of the shaft. My vice even cracked trying to press them out.

It looks like some plastic type stuff was put in the little holes to fill the inside grove instead of clips. Any of you folks ever run across that issue or design. I am guessing these are the original U-joints from the factory in 83.

Yes there is plastic in the grooves, sense your vice cracked i would grab a punch and a BFH and go to town on it. That is what I had to do with my drive shaft to change out some of the old joints.

[Maxxd07]

Originally Posted by Palf70Step

That was the problem, a hole in the yoke. I have the other yoke that came with the tranny (no hole) off and ready to install.

However, the U-joints on the drive shaft have no clips and the U-joints are not coming out of the shaft. My vice even cracked trying to press them out.

It looks like some plastic type stuff was put in the little holes to fill the inside grove instead of clips. Any of you folks ever run across that issue or design. I am guessing these are the original U-joints from the factory in 83.

A torch will make your life WAY easier. That is the proper way to remove the factory plastic. It doesnt take much, as a small propane torch will work too. Heat the yoke up and the plastic will come out of the holes. Your u-joints will come right out. The new u-joint will come with clips and dont forget to install them or bad things will happen! (Ask me how I know , neighbors fresh restore 71 SS Chevelle)
P.S. I dont know about new vehicles but the plastic in the yokes was used into the later 2000s pickup driveshafts.

[burb1085]

yea I had the same problem on my th350. After I fixed the weep hole it decided to start leaking where the detent cable meets the trans. Fixed that up and now its leaking some wheres up by the torque converter, probly the darned pump seal.

[woodridge]

Word of caution. If the tranny has the internal O-Ring to seal the yoke and the vent hole is plugged in the yoke, you can wipe out the thrust bearings/washers in the tranny. The air in the yoke has to vent or it will create vaccum/presure as the yoke moves in and out. Seen it happen too many times.

[Palf70Step]

Originally Posted by woodridge

Word of caution. If the tranny has the internal O-Ring to seal the yoke and the vent hole is plugged in the yoke, you can wipe out the thrust bearings/washers in the tranny. The air in the yoke has to vent or it will create vaccum/presure as the yoke moves in and out. Seen it happen too many times.

I think I should be OK Woody. The non-hole yoke came from the vehicle that my replacement tranny came from, so I will assume that this one was designed to be without a hole.

Worse I can do is blow it up and start over again.

[STOCKISH]

Originally Posted by woodridge

Word of caution. If the tranny has the internal O-Ring to seal the yoke and the vent hole is plugged in the yoke, you can wipe out the thrust bearings/washers in the tranny. The air in the yoke has to vent or it will create vaccum/presure as the yoke moves in and out. Seen it happen too many times.

If it had the internal seal the fluid wouldnt be leaking through the yoke.


Definately heat the yoke with a torch and the plastic will squirt out! Looks like a worm. And there will be alot more than you would think. Probably will squirt out 3-4 inches from each side!!

Glad you got the leak fixed buddy!

[gchemist]

It's marking its territory. I have the same problem on a $2K transmission. I gave up. I'll just abuse it to make up for it.

[406 Q-ship]

That seal is NOT leaking, it is coming from the weep hole in the yoke itself. The weep hole is behind the u-joint and is there to allow air to not get trapped in the yoke between the output. Clean the area well with brake clean and put a dab of silicone sealer on the tip of your finger and place it over that weep hole. To toss that amount of fluid that looks like is dripping off the yoke, your trans fuild level might be a bit high.

700R4 transmission are natural weapers, when left to sit the fluid level is higher than the oil pan split line with the case. So fluid just wicks past the pan gasket, it is a fault of the 700R4/4L60. Getting a deeper pan and resetting the dipstick will fix this problem.