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08 Suburban transmission fluid leak / next steps?


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RoboDisko
User

May 25, 2018, 5:50 PM

Post #1 of 10 (399 views)
08 Suburban transmission fluid leak / next steps? Sign In

Hi. I'm working on a 2008 chevy suburban 1500 4wd with the 5.7L 5.3L. 130,xxx or so miles. I'm pretty sure, but not certain, the transmission is the 4L60-E. A few days ago we were doing some towing maneuvers and noticed oil leaking from the vehicle. The oil ended up being Dexron VI, and it was dripping off of the transfer case. Parked it for the day planning on not driving it until it could be diagnosed.

Today I got under it to check it out. Turns out that the fluid is leaking from between the transmission and the transfer case. Further, I noticed that the transfer case was coming off of the transmission! This created a small gap that the fluid could leak out of. I can move the transfer case around a little bit in relation to the transmission, all of the mounting bolts were loose and could be easily turned with fingers, but still on the vehicle.

Anyways, checked the transmission fluid and it was on the very tip of the dipstick, which isn't very far away from the lower cold safe level mark. The fluid is in good condition as it was changed about a year ago and hasn't been driven much since. However, I noticed a moderate amount of metal shaving paste on the dipstick with the oil.

The vehicle has had a medium-speed medium-load vibration that is clearly tied with this issue. It's had the vibration for a long time, at least a year perhaps? For example, when holding speed at speeds around 45 mph there would be a noticeable vibration, more or less throttle and it would go away.

I'm not really sure what to do next. I do have some questions on this drive line setup. With fluid leaking from between the transmission and the transfer case, are we looking at a failed transmission seal, a failed transfer case seal, either, or is it normal for ATF to be there? I've read that this transmission and transfer case use the same Dexron VI on this vehicle, and even that they share the fluid between them. Do they share fluid? Further, is a little bit of metal paste on the dipstick something I should be directly addressing?

I'm thinking I'm looking at a bad bearing and a bad seal, but I'm not sure if those items are on the transmission or transfer case.

Here is a link to a picture of the paper towel I used to check the transmission fluid and found the metal paste on:
https://photos.app.goo.gl/Tmj90Y8kIwwrHJyh2


(This post was edited by RoboDisko on May 28, 2018, 10:35 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 25, 2018, 7:44 PM

Post #2 of 10 (381 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Site's trans tech may be by or not soon in the mean time you've already said enough to scare anyone. You found it not even fastened in, just finger tight, not sure of which engine or transmission (they didn't normally use a 5.7 in 2008) and it vibrates and leaks! What a shock!


Doesn't sound like you are going to put this together so why not find a transmission shop to take this on and forget it stick with what you do?


T



RoboDisko
User

May 26, 2018, 10:57 AM

Post #3 of 10 (361 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Ahh, you got me. It's a 5.3l. I've been working on our boat that is a 5.7L. I mean, what's 400mL on these things? 20hp? I work on too many stupid v8's to remember the exact displacement of each of them.

Working on cars is one of the things I do. I'm just trying to understand how this vehicle's drive train is set up, so I can understand what's broken before pulling the transfer case.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 26, 2018, 11:38 AM

Post #4 of 10 (353 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Just wait for gsferraro to stop by. He is the transmission expert.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



gsferraro
Enthusiast

May 27, 2018, 4:07 AM

Post #5 of 10 (335 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Hello, If this is a 4L60E trans, there is no rear seal. In between the trans and the transfer case is a gasket. There is a front seal on the transfer case, they rarely go bad. Are you sure this is a 5.7? i looked up the car through shop key pro and came up with either a 5.3 or a 6.0. They do not share the fluid they have separate fills. f your seeing something on the dipstick, drop the pan and see how the pan looks (clean or not) How does the car shift? Gary
Sorry for late response, my shop is packed


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 27, 2018, 4:56 AM

Post #6 of 10 (329 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

He corrected the engine size Gary. It's a 5.3.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



gsferraro
Enthusiast

May 27, 2018, 9:05 AM

Post #7 of 10 (320 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Ok, yes i see, missed that, thanks HT. Enjoy the Holiday


RoboDisko
User

May 28, 2018, 10:32 AM

Post #8 of 10 (303 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

No problem, thanks for the help!

The shift quality hasn't changed noticeably in recent years. It's a little bit harsh, but otherwise good. (I prefer the term 'sporty')

The amount of metal paste on the dipstick is rather small. I'm reluctant to drop the pan unless we have a pretty good reason to do so. Did you look at the picture I linked to the dipstick swab?

At the moment I'm thinking to just re-torque the transfer case back on, top the transmission fluid, and see how it's doing. Does that seem reasonable?

The gasket between the transmission and transfer case appears to be completely gone. How bad of a person am I if I tighten it up and see if it leaks? If it does, I'm no worse off than before. Alternatively, how difficult is the transfer case to remove from the transmission, to replace the gasket?


gsferraro
Enthusiast

May 28, 2018, 4:19 PM

Post #9 of 10 (293 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Hello,
Saw the picture, didn't really look that bad, if there is a space inbetween the trans and the t-case, maybe you can clean it and put some silicon to stop the leak. If all looks ok, that would be fine to tighten it back up, but try to get some kind of sealer or it still may leak,( no rear seal on the trans)


RoboDisko
User

May 30, 2018, 11:30 AM

Post #10 of 10 (267 views)
Re: 08 Suburban transmission fluid leak / next steps? Sign In

Ok. I didn't have any good sealer on hand to seal it, so I just tightened it up to see how it would do. That seems to have fixed the vibration at speed issue, which really puts some doubts on how tight it's been over the last year or so... I'm watching it very closely for a leak, and I'll get it fixed if there is one, but we haven't seen anything leaking yet.

If it starts leaking again, how difficult is it to remove the transfer case to replace the gasket, as opposed to just using a sealant?






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