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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: philo_beddoe on March 12, 2016, 04:42:21 pm

Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 12, 2016, 04:42:21 pm
Noticed small puddle of trans fluid dripping from front u joint. Where is it leaking from and whats the fix? Thanks!
From the looks of the last pic, looks like its spraying when driving.
(http://uploads.tapatalk-cdn.com/20160312/ad800ded0759939069e56af08a64918f.jpg)
(http://uploads.tapatalk-cdn.com/20160312/d45bbe050544c7a84d65c538c1bd5d3c.jpg)
(http://uploads.tapatalk-cdn.com/20160312/2815e58f79b4bb038143bda573af448e.jpg)
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 12, 2016, 07:33:23 pm
Do you see that little dot in the middle of the slip yoke on the trans. That hole will start to leak over time. This is very common for slip yokes with that hole in the middle. 2 fix it you can either pull the slip yoke out, clean it, put RTV silicone on both sides, wait till its fully dried, then lube it and reinstall it. Option 2 would be to remove and clean it, weld the hole closed on the outside, then lube and reinstall. Option 3 would be to replace it with a slip yoke with no hole.

This is a very common thing with slips yokes with the hole. Tons of them have been repaired and last a real long time with just silicone on them and your good to go.

Also, since you have the slip yoke off, you can if you so choose, replace the output shaft seal. It just presses in the end of the tail shaft housing. They are stupid easy to remove and replace and the a new seal is cheap. If it's not needed don't bother, or do bother, either way it's like an extra 10 minutes if you do want to replace it.


Note, I can tell by your pics, the output shaft seal is not leaking, the end of the tail shaft housing is clean, no appearance of fluid seeping or leaking out and the front half of the slip yoke is clean also. Yet you have a drip of trans fluid, it's that hole in the middle. Easy fix.
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 12, 2016, 07:49:22 pm
Hey man, THANKS! Thought i was in trouble again. I just went through the dark side and back with my engine situation. I'll get on this one right away.  Appreciate the quick response.
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 13, 2016, 12:00:50 am
Your welcome.
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 13, 2016, 08:02:26 am
theres a oring you have to replace to fix the problem. the point of the weep hole is to vent the yoke from when it slides back and forth on the shaft when your suspension flexes
Title: Re: Tranny dripping from front U joint
Post by: gunrac on March 13, 2016, 08:20:02 am
theres a oring you have to replace to fix the problem. the point of the weep hole is to vent the yoke from when it slides back and forth on the shaft when your suspension flexes

Now that makes better since to me.....
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 13, 2016, 08:32:34 am
http://www.73-87.com/7387garage/drivetrain/yokeleak.htm
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 13, 2016, 04:33:23 pm
Great, i just plugged the hole with rtv, of course it can be cleaned out, i'll get a new o ring.

Is this job easy? How do you remove slip joint and get at that o-ring?

According to that article it looks tough.
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 13, 2016, 04:40:02 pm
The article says you have to remove the tail shaft housing to replace the o ring. Which is not hard but more work and you will spill a little more fluid. If you already cleaned and put RTV silicone on it. Don't worry about.
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 13, 2016, 04:40:12 pm
not hard, the article has the tailshaft removed, you dont have to do that. just take the bolts of the u joint strap on the rear axle. pop the driveshaft out take some electric tape or ducktape and wrap it around the u joint so the caps dont fall off and slide the slip yoke out. you should see the o-ring, dont know the technical name fore it so you might have to just remove it and take it to the parts store to get a new one
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 13, 2016, 06:25:37 pm
Ok, that sounds better, thanks.
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 13, 2016, 09:40:02 pm
This manual ought to help me. I printed my own from the pdf file on this site. This thing is like 800 pgs. This is only volume one of two.
(http://uploads.tapatalk-cdn.com/20160314/71556c6dd1678e779064447249a39aa9.jpg)
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 13, 2016, 10:02:05 pm
I have a hard copy service manual for 1979, it's 1,033 pages.
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 13, 2016, 10:13:33 pm
I have been checking a ton of other sites on that slip joint weep hole. Nearly all either weld it closed, use JB Weld or permatex. Then they report later on that the problem is solved, no more leaks or any OTHER problems.
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 13, 2016, 10:18:57 pm
The point of a pressure relief is pretty much mute, the pressure that's created isn't 120 psi. If lots off other sites with thousands of members say they seal the hole and never have an issue then why be worried about it. All the technicians at work who have been working on chevy's for at least 10-15, a few over 20-25 and 1 over 30 years have said the same thing. Weld it or seal it shut and don't worry about it. I wouldn't suggest it if I wouldn't do it to my own truck. Luckily, I don't have a weep hole in my slip yoke. You will be fine. If I am wrong I'll eat my hat.
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 13, 2016, 10:29:39 pm
I'll send you some salt and pepper!! LOL,,  Well, its sealed now, permarex this morning, havnt started truck since.
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 13, 2016, 10:49:31 pm
Not the first time I've used that last sentence. Also not the first time I've eaten my hat so won't be needing the S&P. Thanks tho.
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 14, 2016, 10:55:52 am
sorry guys i fell asleep after posting the first part heres the second lol

tail shaft housing might have to removed also then the cross member. never had to do it since most my trucks are 4x4s and the o ring isnt in all trans just a few styles and i only had one of those and it didnt leak.

i dont see why you cant just fill the hole with rtv or something but why even worry about it, i mean if gm thought it wasnt needed then why did they do it? but then why didnt other trans have it?
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 14, 2016, 10:58:45 am
http://www.stevesnovasite.com/forums/showthread.php?t=74037
Title: Re: Tranny dripping from front U joint
Post by: 76LongBox on March 14, 2016, 03:17:54 pm
Just throwing this out there too, to go along with the guys saying just seal up the hole.

When I replaced my engine/transmission a couple of years ago, I went with a TCI Streetrodder transmission. I used my existing yoke, and soon found out about the weep hole.  I contacted TCI about the O-ring, etc., and they told me they didn't build their transmissions to use them at all. Their advice was to seal the hole or get a yoke without the weep hole. Just to simplify everything, I bought a new yoke from TCI that didn't have the weep hole, and all is well.
Title: Re: Tranny dripping from front U joint
Post by: Irish_Alley on March 14, 2016, 04:10:33 pm
(http://s5d2.turboimg.net/sp/6f903caeea4fcf4b55d5304c8fc995e9/seal1.jpg)


http://forum.73-87chevytrucks.com/smforum/index.php?topic=23918.0


this is the o-ring
http://www.makcotransmissionparts.com/64380.html
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 14, 2016, 04:37:37 pm
The weep hole is useless.
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 14, 2016, 06:07:37 pm
$1.03 for that part?!!!!

http://youtu.be/rJnm7janvUA
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 14, 2016, 06:18:34 pm
Ok, enough goofin off, can a worn yoke cause an intermittent driveline vibration, therefore resulting in that leak? ONLY while under load AND moving i will get a mild vibration (i know, thats all i need right), like this,,,hummm-smooth,,,hummm-smooth,,,hummm-smooth. It is smooth as silk while in park or neutral.  Definitely driveline related. Not to mention, my left exhaust is pressed tight against the frame crossmember, Vile mentioned that a while back.
Title: Re: Tranny dripping from front U joint
Post by: zieg85 on March 14, 2016, 06:37:06 pm
2 piece drive shaft?
Title: Re: Tranny dripping from front U joint
Post by: VileZambonie on March 14, 2016, 06:54:33 pm
Kill two birds, witness mark the yoke to the u-joint. Pop the driveshaft out (careful not to drop a cap and lose your needle bearings) and clean the yoke with some brake clean. You can put some RTV in the weep hole and it won't drip anymore. Install it 180° from the original position and see if it changes the pitch or speed.
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 14, 2016, 07:50:52 pm
I think i can do that. Believe it or not, i was able to get my small finger between the u joint and weep hole and press the rtv in the hole, but then had to use a screw driver as a small putty knife, but i sealed it good and neat. No more drip. 

I will still do the 180 degree thing though. Thanks V!

Zieg,,one pc drive shaft.
Title: Re: Tranny dripping from front U joint
Post by: zieg85 on March 14, 2016, 08:12:44 pm


Zieg,,one pc drive shaft.

Vile beat me too it on the one piece.  Remember just because there seems to be no play in a u-joint it could be dry and starting to go bad.  When you take the shaft out carefully rotate the loose caps and the other ones in the shaft itself
Title: Re: Tranny dripping from front U joint
Post by: 1967KaiserM715 on March 14, 2016, 08:13:54 pm
Might be the exhaust, my Jeeps exhaust was contacting the transmission cross member for a while, and under acceleration, or at speeds between 35 and 45mph, it would "hum" off the cross member. I could feel it in the floor as well(Cherokee, unibody)

Sent from my Lenovo TAB 2 A10-70F using Tapatalk

Title: Re: Tranny dripping from front U joint
Post by: zieg85 on March 14, 2016, 08:22:17 pm
Can you crow bar the pipe down enough to jam a wooden shim in it to separate it from the frame enough to see if it makes a difference?
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 14, 2016, 10:12:59 pm

Can you crow bar the pipe down enough to jam a wooden shim in it to separate it from the frame enough to see if it makes a difference?
I thought of that, and now that you mention it, i think i can shim a piece of wood in there, its not so hot it will cook the wood now...will it?
Title: Re: Tranny dripping from front U joint
Post by: zieg85 on March 14, 2016, 10:15:59 pm

Can you crow bar the pipe down enough to jam a wooden shim in it to separate it from the frame enough to see if it makes a difference?
I thought of that, and now that you mention it, i think i can shim a piece of wood in there, its not so hot it will cook the wood now...will it?

shouldn't, you should know right away if that is the route cause.  Let us know
Title: Re: Tranny dripping from front U joint
Post by: philo_beddoe on March 14, 2016, 10:18:48 pm
Will do, gonna try it first thing in the am. I figure when i put the H pipe in there i'll set it correctly away from that cross member.
Title: Re: Tranny dripping from front U joint
Post by: zieg85 on March 14, 2016, 10:31:57 pm
good plan
Title: Tranny dripping from front U joint
Post by: philo_beddoe on March 15, 2016, 04:53:20 pm
I didnt have to put a shim in there, i used the tire iron from my f-350 and pryed it down just a tad, enough not to touch the crossmember. We'll see how it is when i leave for work in the morning.

Also, its been a couple days and not one single drop from the peep hole, i mean weep hole.
Title: Re: Tranny dripping from front U joint
Post by: LTZ C20 on March 15, 2016, 07:23:48 pm
Peep hole.... lol