DRIVE SHAFT at T/Case OUTPUT SHAFT SEAL LEAKING AGAIN?????? [Archive]

cowboywildbill

10-19-2007, 04:56

Just took our truck into our Dealer for warranty. I was underneath looking at the airbag install and noticed the telltale ATF sling on the underside of the trans hump right over the rear of the transfer case at the driveshaft. I wiped it off and checked the transfer case level, it was only down about 1/2 inch below the fill plug. So no harm there. We had just returned from a round trip of about 900 miles towing. The dealer said he had seen a few of the seals fail on everything from 1/2 tons to 1 tons, even though they are different seals.
The tech was a young guy, I think he is just starting his career. He was just getting aquainted with the D/Max trucks. He seamed very capable and eager to be on top of them.
He was going to change the fluid in the trans case and replace it with the all-track fluid. I said that I was under the impression that Dex III or the new VI was the prefered fluid. The older tech thought that the all-trac was what was being used for replacement also. They didn't have a problem with just topping it off with Dex VI, is it V or VI? Anyway what is the correct fluid for the case? Also they had an 06 LBZ getting an EGR valve replaced. The senoir tech said that he had done a few of them recently. This is a small dealer with only two techs, but they sell a lot of vehicles. They were great about getting me in the same day while I waited. The techs seemed to be very capable, but I'm sure they get pretty busy, since there are just two of them. The dealer is Bogley Chevrolet in Thurmont, Md. They also just sold the 08 3500 LMM I posted about a week or so ago. They already had another one on the lot to replace it.

cowboywildbill

10-22-2007, 04:10

I looked under the truck next morning and saw ATF sprayed on underside of the hump again. I wiped it clean again and drove it to the dealer.
The dealer put it on lift and it didn't show any signs of leaking for the 4 mile trip back.
The tech said he forgot to wipe the fluid off after the new seal was installed. No problem, I guess that explained why I saw what I thought was another leak.
We took a trip towing about 100 miles this weekend. I looked under the truck when we got back. I see there is fluid spayed around the hump again. It doesn't look like it is as much as before, but it does look like the seal is leaking again. I asked the tech if he put a little lube on the lip of the seal on the first install, and he said they are pre lubed now. He did use gasket sealer for the install into the tail shaft and used a seal installer to drive it in. I guess we will be going back today and see if another seal will fix it. Any idea's?

DmaxMaverick

10-22-2007, 08:20

I don't see how late models will be any different from earlier models, so this may apply.

I've had a couple vehicles (not brand specific) with this issue. Replace seal, only to see it leak again. In the end, replacing the yoke was the answer. If the sealing surface isn't perfect, it will leak at some time. When they do, they usually keep leaking until replaced or repaired. Sometimes, a Speedy-Sleeve will work. Sometimes not. It's a new truck still under warranty, so you shouldn't have to worry about that. Yours is leaking pretty quick, so the dealer shouldn't have too much trouble nailing it. That doesn't mean they will:rolleyes:, but should.

cowboywildbill

10-23-2007, 05:03

I agree, I felt the yoke when he had it out of the truck and it felt OK. I remembr years ago when I was spinning wrenches I had a car come back with same problem. I put the calipers on the yoke and it was out of round? Replaced the yoke and seal, problem solved.
We will see what happens today. I take it back this afternoon.

More Power

10-23-2007, 13:40

Have them check the transfer case vent hose and cap. The vent is there to equalize pressure. Just a thought....

Jim

cowboywildbill

10-24-2007, 08:35

Hi everyone. Jim, I checked the vent and it is dry up top I was thinking the same thing. I went back to the dealer and he said the old seal is worn funny on the end of the lip. They said GM wanted it back, maybe there is a problem with them? They opted to order a new yoke and seal and will try to install later this week if parts come in. I guess we will see. They said that they heard of another dealer that had a driveshaft that was just a little too long cause the seals to fail in a truck. Apparently when they would tow it would eat the seal? Who knows. I guess something in assembly got out of whack when building the shaft. And when the truck was loaded it would push the shaft too far in and the yoke would chew up the seal. I would have thought that would eat the bearing also. I'll let you know what happens.

cowboywildbill

10-27-2007, 18:00

Went back to the dealer Friday afternoon. They put in a new output shaft seal on the transfer case and installed a new yoke on front of driveshaft. New yoke came with a new U-joint. They put it on the driveshaft and reinstalled it. They cleaned up the tunel over the driveshaft and checked the t-case level. I drove it 70 miles, not towing. I looked underneath and there is ATF fluid slung under the hump again. It is definitley comming from the seal. I wiped it off and ran about 80 miles today not towing and I don't see any fluid slung out so far.
Could it be a problem with the bearing in the transfer case? Or my airbags changing the drive shaft angle/length? I don't run much air in firestone airsprings, empty. 20 lbs, today I ran 5 lbs. I am puzzled, I wonder if GM has a problem with the seals? Any idea's ?????. We couldn't find anything wrong with the original yoke that came out or the seal they had replaced last Thursday a week ago. The tech did say that the first(original seal) was chewed up where the yoke would come in contact with it. I am going to check the vent and see if it is working tomorrow. I guess if it is clogged, it could be building up pressure and blowing it out of the seal? I guess I'll try a little air into the fill hole and see.
I haven't called the dealer about this last repair because they won't be in until Monday.
I wouldn't think it could be the airsprings??? Anybody????

cowboywildbill

10-27-2007, 18:10

It's leaking again, after a new yoke and seal. I am going to see if the vent is working. It might be pushing fluid out of the seal if it is building up pressure.

mark45678

10-28-2007, 09:49

any vibration at say 70 mph +? did they replace the tail shft bushing? is the T case over full maybe the front seal in the tcase is leaking from the trans to the tcase ?

cowboywildbill

10-28-2007, 10:46

They did not change the bushing. When I first saw the leak, I checked the case and it was a little low about 2" below fill plug, I know it was right at the fill hole before the leak. I don't notice any vibration. I was thinking maybe bushing or bearing also.?? Has anyone seen this occur over again in a 3500?

More Power

10-28-2007, 16:07

A couple of observations....

1- As was mentioned earlier, a worn tailshaft bushing might allow the splined yoke to move enough to hasten seal wear, but I doubt that's the problem here. You'd have to be seeing a lot of lateral play in the spined components and at least a few thousand miles before a properly installed seal would begin leaking.

More likely is:

2- A local mechanic friend and I removed the transfer case from my 2001 GMC this summer to install a pump flange upgrade (that prevents the possibility of excessive case wear and subsequent leaks). As part of the installation, the mechanic also installed a new rear output seal. He told me during the seal installation that the tension spring, that surrounds the lip of the seal, can jump out of its groove when using a seal installer and mallet. There is a trick to prevent this from happening.

So, there's a chance the tension spring jumped off the seal when your new seal was installed.

Jim

Mark Rinker

10-28-2007, 18:13

When I bought the '06 K3500 earlier this summer, I took it into the local dealer for a 'once over', fluids, etc. since the truck's service history was all new to me.

Suprisingly, they replaced the driveshaft yoke. There must have been a leak or something to prompt them to do so.

I'll stop by tomorrow and ask the tech if he remembers what or why it was bad - will print this thread (now merged with your first post) and have him read it.

cowboywildbill

10-29-2007, 11:31

Thanks, I would appreciate any idea's. I stopped by and told the tech that it flung fluid again. He was puzzled and said he was going to try GM tech line. I am going to take it by and let them test the vent.

cowboywildbill

11-04-2007, 11:29

Drove it 200 miles not towing, no leak. Drove it 160 miles towing, no sign of leak or fluid under tunnel. Maybe it stopped leaking or maybe it only leaks when it is hot out, it has been cool weather since I last saw a leak ??????

lmholmes11

12-16-2011, 06:08

MorePower, what is the trick you mentioned to not mess up the spring when installing the seal? And if not using a seal installer how do you get the new seal in?

DmaxMaverick

12-16-2011, 09:10

Have a look at THIS THREAD (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=36359).

More Power

12-16-2011, 11:40

MorePower, what is the trick you mentioned to not mess up the spring when installing the seal? And if not using a seal installer how do you get the new seal in?

DmaxMaverick's post in the linked thread is excellent.

In my case, since the tailshaft housing was off the transfer case, we used a press (and properly sized bushing) to press the new seal into the housing. The mechanic made a big deal about the potential for disloging the tension spring when using a mallet, and said if we were doing this on the truck we'd use a method similar to that described by DM. Small shop mechanics don't want any comebacks...

Jim

MikeyB

12-16-2011, 16:58

I have a 2006, Chevy, D/A, CC, DRW, LBZ, 4X4, with 123,860 miles. Recently it was spraying transfer case fluid on the bottom of the cab. It took some time to locate the precise cause of the leak. It turned out to be the front driveshaft yoke leakng behind the U-joint. On the back of the yoke there is a cap much like a freezeplug and it was seeping fluid around this cap. I did not need to replace any parts. I cleaned the area around the cap and the yoke and sealed the seam with J B Weld. It has not leaked a drop since and it is towing a 38 foot, 16k, 5th wheel full time.

Funny! I had the same problem and thought it was the dreaded hole in the transfer case. Found mine was leaking in the same spot as yours and fixed the same way with some JB weld.

Mike

lmholmes11

12-22-2011, 19:51

for some reason i'm not seeing the "freezplug" you guys are describing on the back of my yolk. I had the pin sized hole repaired on the transfer case housing under warranty so i know its not leaking from that. I am thinking that i have seepage from where you guys are talking about. Hoping that I can just fix with JB welb like you guys have done. I dont think the seal is leaking. I have attached a few pictures.

DmaxMaverick

12-22-2011, 19:56

lmholmes11

12-23-2011, 07:23

Ok thank you. I will replace the seal

CoyleJR

12-23-2011, 11:37

DmaxMaverick

12-23-2011, 12:10

I just looked at the pictures of your TC leak and in my opinion the yoke is leaking at the freeze plug. The first picture shows an almost dry seal and yoke. The second picture shows a wet yoke and U-joint. The fluid is leaking from the freeze plug/flat wet area between the U-joint and the yoke shown in the second picture. Go to Walmart and buy some brake parts cleaner, JB Weld fast dry and a tooth brush size wire brush. Clean the flat area of the yoke (freeze plug) behind the U-joint and seal the seam between the round plug and the body of the yoke with JB Weld.
DmaxMaverick posted a link (read this thread) to an old posting that I had placed about this same problem. If you do replace the seal I would do the JB Weld fix just to cover all the bases.
Good Luck and let every us know what happens.

Merry Christmas
John

I'm still trying to grasp this "freeze plug" you guys are sealing with J-B weld. Certainly you don't mean the yoke vent????? It's there for a reason, and sealing it will cause more serious issues than a little leak (output shaft bearing and pinion bearing failure, to start with). Proper packing of grease on the spline will prevent any leakage at the vent.

CoyleJR

12-23-2011, 15:38

DaxMaverick,

The yoke vent sounds like the correct name for the part. I never said to plug the vent hole in the middle of the yoke vent. If the yoke has a vent hole, I have seen many that did not have a vent hole in the center. My problem was with the TC fluid leaking from the seam between the yoke vent and the body of the yoke. I suggest that sealing the seam with JB Weld is an easy inexpensive way to make certain that it is not leaking.
If you look at Imholmes11 second picture you will see that the yoke vent/U-joint area is quite wet with fluid and the first picture of the seal/front yoke area is not very wet.
My truck has about 60k miles on the JB Weld fix and it has not leaked a drop.
Merry Christmas
John

DmaxMaverick

12-23-2011, 16:28

If we are looking at the same pic, what I see is a wet seal lip and tailshaft housing, with fluid "wicked" about 2/3 up the joint yoke. If the vent were leaking, the entire joint yoke would be wet, with more than just the trickle down the tailshaft housing. Also, there would be a significant amount of fluid at the outer area of the U-joint and the body pan, due to centrifugal affect.

In any case, there should be no fluid, or any significant amount, at the rear area of the spline yoke. This is disastrous, and will lead to a LOT of damage. The leak is only symptomatic. Fix the leak w/o sealer, or look forward to significant premature drivetrain failure. The "freeze plug" is no more than a dust cap, with an orifice to allow venting, and prevention of outside contamination. There should be no ATF on either side of it. If the cap is leaking at the perimeter, it is very likely there has been fluid under it, which caused it to leak, in the first place. Sealing the "leak" only hides the leak, which is a designed indicator of another problem (like a weep hole on a water or fuel pump).

Older splined slip yoke designs had a grease zerk, but these were discontinued. The reason for discontinuing was over-greasing, which caused the same problem as a leaky one. There should be only an air gap between the end of the output spline shaft, and the head of the slip yoke.

lmholmes11

12-24-2011, 12:34

Do you need a press for these u joints to remove? On the semis I've always used a press with an impact. Looks like just remove the snap ring and hammer the u joint out of the yolk? Does the yolk then just pull off? I've only done seals and yolk/u joint work on semis. Sorry for so many questions!

DmaxMaverick

12-24-2011, 14:58

Remove the driveshaft at the rear joint (4 bolts on 2 caps, mark the joint and pinion for exact reinstall, tape the joint caps on, so they don't fall off), then slide the yoke out of the TC. Nothing holds it in there but the shaft. Have a container handy, as there will be some ATF that will dump out once the yoke clears the seal (unless the level is very low, and/or you are pointed steep downhill). There's no need to disassemble U-joints unless you are replacing them. It's as easy as it it can be, so don't try to make it difficult.

lmholmes11

12-27-2011, 14:02

DmaxMaverick

12-27-2011, 15:28

Thanks for the help Dmax, i plan to replace the seal ASAP. When you said that fluid could be disasterous there do you mean just by leaking out all the ATF out of the T/C? I have a 200 mile trip that I need to take the truck on tomorrow. If I keep an eye on fluid level should it be ok?

Leaking out all the ATF could be disastrous, but I was referring to having the airspace between the yoke and shaft full of fluid. Fluid is not compressible, and will lock the fore/aft motion of the driveshaft (caused by rear end compression/retraction), to the TC output shaft. A "slip yoke" is used here for that very purpose. If it isn't leaking out of the vent, then that's not an issue. A leak at the vent indicates fluid where it doesn't belong, and sealing it compounds the problem. If the cap is leaking, in any way, there's fluid on the other side of it, and less air to allow for movement. Fix the minor leak now, or replace the TC later.

You should be OK if you keep an eye on the fluid level (I would do it, if necessary). 200 miles isn't far.