2004 Yukon 8.1, TCase pinhole & water pump

[jeff in co]

Took my annual trip to Idaho with the boat towing with the Yukon XL. I had vaguely heard about some T-case issue months ago but didn't really pay attention to it and didn't really know it applied to me.

Well, I guess it does. While towing, I pulled into Bozeman for gas. Walked around and noticed some oil on the bottom of the truck and the front half of the boat. Looking a little green, I was wondering....looks like T-case fluid. Thinking it's a small leak, I head towards Butte but am paying a little more attention. Started seeing oil "sparkles" show up more and more on boat window so decided to check it again before the final pass into Butte.

Yea, it's leaking pretty good now and I'm about to call it a day. Unfortuanately, I now had to decide, call a tow truck and deal with truck and boat, or try to make it over pass and into Butte. Took a chance....

Made it.

Found a local shop on Sunday to at least evaluate (real nice guy). Put it up and sure enough, T-case. Check level and it was almost empty. Because the fluid is usually bought only at a GM dealer, we decided to not work on it until Monday (great guy though....was willing to work on Sunday to get me back on the road!)

Anyways, Monday comes and we get it apart. Sure enough, I am also a victum of the broken spring that keeps the pump from moving. So it slowly just eroded a hole into the case cover.

Called dealer....wanted $600+ for just the cover (and 2 day wait). Owner arrived and called a tranny shop. Found a rebuilt cover and also the "updated" pump in stock for about $385.

Picked it up and installed. Back on the road!

Very fortunate!

 

[jeff in co]

This is the oil they added to Tcase instead of Autotrac....

 

[jeff in co]

The mechanic also noticed my water pump was leaking. 2,000 more miles and I'm now back home.

I picked up a new pump from Advance Auto but was wondering if I also need to replace the fan clutch too? Is this a common thing or re-using the old one OK?

 

[sweetk30]

problem is called pump rub . huge problem on that style tcase . and your lucky . . . . some have had HUGE damage when not found in time like you did .

 

[63chevyll]

Glad you got the carse cover fixed.

About that fluid. I have.never used anything thicker than atf or autotrack.

I know you can use dex 6 + a posi.additive, or the auto track fluid. I assume your Tcase controls has an auto mode.

As far as fan.clutch, no need to replace it unless its loose or leaking or the little spring on the front is.broke

 

[jeff in co]

I did ask the local GM dealer (Al Serra) about the fluid and the service manager said it was OK. I may still flush it at some point and replace with autotrac fluid (yea, I have the auto mode t-case).

I'm going to pull off the clutch tonight and see if it's loose or not. I did pick up a new clutch just in case I need it......thanks!

 

[Fubeca]

I've the same t-case in my suburban. I'm surprised the dealer okayed that fluid - they were adamant about using the blue stuff.

I just put in a rebuild from transfercase express - so far I'm very pleased. I really love that suburban - does such a great job towing with a family!

 

[jeff in co]

I've the same t-case in my suburban. I'm surprised the dealer okayed that fluid - they were adamant about using the blue stuff.

I just put in a rebuild from transfercase express - so far I'm very pleased. I really love that suburban - does such a great job towing with a family!

yea, I was a little surprised too. I've delt with him quite a bit over the years. Besides the question about the T-case, I did ask him about a few bolts that were sticking out when we were working on the truck in Butte. The mechanic said, "hey, come over here and see if you see anything out of the ordinary." I'm like, OK....

Saw these two bolts just sticking out without a nut for the front end cross member. About a month earlier, I had the Chevy dealer install new cooling lines for the engine and tranny (4 lines). I was suspecting they removed this cross member to gain better access to the lines....just don't know for certain though. They were the last ones that touched the truck.

I was basically asking the service manager if it was possible. Didn't get a hard, "NO" but he didn't think it was usually needed for line repair. Regardless, I wanted to bring it to his attention because of a safety concern.

He agreed. A few years ago, I had an alignment on the blazer at the dealer and they forgot to tighten the drag link to the steering box. Real loose.

So now I had two potentially hazardous situations that the dealer performed and I wanted him to know. He looked up which mechanic did the work and it was the same one both times. He is now blocked from working on any of my trucks.....

 

[Fubeca]

Wow! Just WOW! - That would freak me out - one of the reasons it is so hard to leave my vehicles anywhere, just so many techs out there who aren't paying attention.

 

[jeff in co]

Wow! Just WOW! - That would freak me out - one of the reasons it is so hard to leave my vehicles anywhere, just so many techs out there who aren't paying attention.

Yea, that's what I said. I had already gone 900 miles towing the boat. And just so you know, I-25 in Wyoming has a speed limit of 80 MPH now. Not saying I hit that towing but....

 

[63chevyll]

Wow. Unfortunately thats not the 1st time ive seen bolts coming out. But if anything about the tcase, just leave it and dont plan on using the auto.function......not like anyone uses anyway.

 

[63chevyll]

Basically, what happens, the clutches in the tcase engage the front shaft and causes the front diff to turn all the time. You would never know.because the front end isnt transmitting power because the pass side front shaft isn't engaged.

So the carrier spins around the spiders all the time and overheats the fluid. So if you check front diff and fluid is like.honey and clean your fine, but if the front diff fluid is dark and you see glitter in it then the tacse is partially stuck in 4x4.