Chevy Trans question

nick c · Jul 25, 2010

I'll start with what I'm working with.

4L80E transmission in my 2003 K2500 Silverado. I was towing my brother's mid-70's K20 truck down to Elma for him. Not sure on the weight.

When we got to our destination I noticed my trailer had a bunch of oil marks on it, little specks everywhere. So I looked under my truck and the chassis had a good amount of what looked like ATF all over it.

On the way there I was keeping an eye on my trans and water temps, granted they are just the factory gauges so who knows how accurate they are but they never got hot, they sat right around the middle at about 200-210*.

So whats the deal, should I be checking for a blown seal or is there a breather on the trans somewhere that I could have pushed it out of?

I haven't had a chance to get under the truck and really take a look, I just got home and it was dark. I'll have to check it out tomorrow.

Any thoughts on what I should look for?

And the transmission never really changed the way it shifted, it still feels solid no slipping that I've noticed.

TreeClimber · Jul 25, 2010

Could also be the vent tube on the transfer case. Could be a transmission slightly overfull, and simply expanded out the fill tube, and dribbled back down the tube and underneath.

You need to go underneath with a can(s) of brake clean and a fresh roll of those blue paper towels. Clean the crap out of EVERYWHERE. Make it look like a new truck underneath. Get ALL the dirt, and ALL the oil, and all the shmutz clean. Then go drive it again for a short trip. Crawl underneath, look for fresh leaks.

ceb0217 · Jul 25, 2010

could be pump rub. (for thoes that dont know) the trans fer case pump rubs a hole through the trans fer case (only a pin hole ) and it leaks atf.

ain'tstuckjustresting · Jul 25, 2010

On my 03' the T/C output seal has weeped for years. Never a drip just always alittle damp. Also, I had a wheel seal go bad at 40,000mi and we just changed one on the bosses 04' last month.

crash2 · Jul 25, 2010

Nick look at the back/top of your t-case for a hose with possable ATF on it--thats the vent for the trans.

zukkev · Jul 25, 2010

ceb may well be on the right track...The transfer case leak he's talking about is a pretty common issue on the newer trucks with the NVG263HD/XHD's---what happens is a little steel clip ("dog sleeve") that's inside the case breaks, causing the 'dog' to vibrate it's way thru the magnesium case-which doesn't take long due to how thin the case material is in this spot...The proper fix is a new dog sleeve and t-case back half...Now I suppose you could repair the leak/hole somehow, however you'll still need to crack the case and replace the 'dog sleeve' with the updated one (different design that's slipped onto the 'dog', rather than being mounted to the case half)....any way you go, good luck!!! If you do indeed have this issue---it's not a difficult job to pull it apart, once it is apart you'll see just how cheezy the whole design flaw is!!!

nick c · Jul 25, 2010

Well I hope its not the pub rub issue, I did a bit of reading and it seems to happen mostly in the 263XHD transfer cases, not as often in the 263HD cases which is what I have according to the tag.

I sprayed it down with brake clean and wiped it clean, including the breather hose. I'll drive it down to Cabella's this morning and check it when I get home and see if theres any new fluid on the case or breather tube.

Thanks for the tips

zukkev · Jul 25, 2010

It's not hard to do the job Nick, but it can be expensive if you buy a new case back half....Seatac Trans has 'em if it is this, and wish to replace the case half...:awesomework:

nick c · Jul 26, 2010

Well I took it for a little drive my Iphone took a crap and I ended up having to go to the Tacoma Mall before going to Cabellas. I checked it at each stop and didn't have any new fluid until I got home last night. It is definetly coming out of the breather tube. I only saw a couple new drops on the end of the tube but the t-case was still dry.

I haven't serviced the t-case or trans in probably 30K miles, my transmission fluid level looks fine. Haven't checked the transfer case level yet but I'll pull the fill plug this evening and check. Why would it be pushing fluid out of the breather?

And Kevin, I plan to order the pump rub fix kit some time before I tow down to KOH in February. I figure it's $200 now or close to a grand later if I don't catch it in time, I'd rather do the preventative thing and not have to worry about it.

crash2 · Jul 26, 2010

$200 for what kit?

nick c · Jul 26, 2010

This kit... http://www.merchant-automotive.com/transfer-case-pump-upgrade-kit.aspx

There's a few others out there but they are right around the same price. If you know of a better (lower cost option let me know). Hell I'd be happy to bring the truck to you and let you do the work, I hate working on these newer rigs. :redneck:

crash2 · Jul 26, 2010

Let me look into it tommorow nick. I know I can do it for way cheaper parts wise. No need to replace the pump as in the field we replace the case half(when they finally dig thru) with a new updated clip and never see them again.

nick c · Jul 26, 2010

Sweet. Thanks Mike. :awesomework:

zukkev · Jul 26, 2010

crash said:
Let me look into it tommorow nick. I know I can do it for way cheaper parts wise. No need to replace the pump as in the field we replace the case half(when they finally dig thru) with a new updated clip and never see them again.

Yup....but the wierd thing is other than the way the clip's mounted (and where!)....I'm surprised they don't come back!! Possibly slightly heavier/thicker material the clip's made from??? Who knows...

crash2 · Jul 26, 2010

zukkev said:
Yup....but the wierd thing is other than the way the clip's mounted (and where!)....I'm surprised they don't come back!! Possibly slightly heavier/thicker material the clip's made from??? Who knows...

The problem is the first design clip cracks/breaks and falls out of place which lets the pump smack the housing causing a hole.

The new clips are fixed so this is no longer an issue.

crash2 · Jul 27, 2010

Its like $8 for a new clip.....

zukkev · Jul 27, 2010

crash said:
The problem is the first design clip cracks/breaks and falls out of place which lets the pump smack the housing causing a hole.

The new clips are fixed so this is no longer an issue.

Yeah, I know the differences between the old and new clips (just did one last week along with a new case half); just seems odd that even with the new clip mounting directly to the pump dog, the potential is still there for the clip to break...that's all! I sat there and looked at the design---no change was made to the case half (ie:thicker amt of material where they typically chew thru), only the clip----If it were me, I'd try and incorporate a hardened steel area (where the dog is) into the case half itself....I guess that's why the engineers get pd the big bucks!!!:redneck:

nick c · Jul 27, 2010

I read a post on one of the diesel truck boards about doing the job, didn't look too overly complicated. It also didn't look like it required any special tools, would you guys say thats true?