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So decided to change my rear diff oil today. Took a ~30 mile round trip this morning and when I got back, I drove it straight into the shop and onto the lift. Lifted it up, drained the old oil, filled it back up. Pretty easy.

Now the sucky part. Looks like the input shaft (pinion shaft?) seal on my differential has begun to leak. The bottom of it is covered with greasy crap and some of it looked wet-ish. I cleaned it up so I can keep an eye on it. But how big a job is it to replace that seal?

Also, been seeing a very small damp spot under the front of my truck in the carport for a few weeks now. So, while I had it up in the air I removed the skid pan to get a look. Very hard to see up in there but it looks like it may be coming from the water pump. I took a few pics -see below. I can see the coolant at the lowest point where the pump mounts to the motor - next to where the lower radiator hose attaches. Cannot see anything above that as it's just too crowded. I also looked from the top and everything I could see / touch up there is dry. I have a slow, steady drip that runs down the front of the motor and drips off the front, driver's side corner on the oil pan flange. Is this the water pump seal leaking? My water pump was replaced back in 2006 about this time of year at 117,000 miles. At 410k now so it almost lasted 300k miles if it truly is leaking. It's a VERY slow leak. Been leaking for a few weeks now and when I topped it off after dropping it back down to the ground, it only took a few ounces to fill the overflow tank.

Anyway, How big a job is the water pump? I was out of state the when the first pump went out and had a dealer do it. I know about removing the starter and using the tool to hold the flywheel while breaking the harmonic balancer bolt, but how bad is the rest of it? Best flywheel tool out there? What size socket for the harmonic balancer bolt?
 

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LHN...We ARE the Joneses
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Is this the water pump seal leaking?
Behind the WP hose inlet, that's the WP weep hole area.

Do a Search, plenty of How To threads and the key tools needed (one posted in just the last few days). Along with all the other things to go ahead and replace, since you've got the front pulled off.

No need for starter removal, as you'll see in the various threads, the flywheel lock tool and socket combo kit is the key.

'02, easier than later models, no engine mounted fan cage to fight with.
 

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Discussion Starter #3
Yeah, I just watched a couple of videos. I may try pulling the driver side inner fender and looking from there as going off one of the videos, the weep hole seems to be visible from there. You can't see crap from top or bottom, that's for sure.
 

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So, another question on the water pump. If I need to replace it... looking at Delco pumps on rockauto, they list 2. One is the "professional" and it comes with the housing and the 2 O-rings for the pipe that goes into the bottom of the t-stat housing along with the other gaskets and O-rings.. This one is $132. AC part # 252994

The other they list is "original equipment" and is just the pump and the gasket and O-rings for the pump itself (none for the pipe and no housing) and is $151. AC part #251723

I really want the O-rings for the pipe to the T-stat due to age and such but I also want a NEW pump - not a reman. Anyone know whether the "professional" is a NEW pump?

$20 ain't gonna make any difference at all but I can't figure out how to look up those O-rings for the pipe and also figure while I'm in there, replacing the housing won't hurt - probably won't help either but.....

I'm guessing that little piece of hose in there is just 3/4" heater hose???
 

LHN...We ARE the Joneses
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Vids are okay (and sometimes wrong on stuff)....but the DF threads are far more descriptive, with much more info.

On your pump choices, look at the pic windows for what you're getting.
Those two acDelco items, one is complete and ready to drop in, the other is just the pump (so seals offered differ).

I think the better choice is the https://www.rockauto.com/en/moreinfo.php?pk=2145076&cc=1380305&jsn=3005 - lower price, complete unit, with the 3 seals you need (oil cooler, pump O-ring, tube O-ring).

Need to search the threads. There's more to it than just a pump.
:wink2:
 

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Discussion Starter #6 (Edited)

LHN...We ARE the Joneses
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OE is just the pump....Pro has the housing.

Gates is big....they probably make the acDelco.
BOTH O-rings for pipe at the WP to the T-stats
There's a single O-ring on that pipe at the WP....which is locally available at most retail auto parts if you booger it up on install (likely).
There is a smaller one on the other end of the pipe, locally available too.

I looked at a few threads on here but didn't see much else
Your removing the drive belt....they're good for 100k miles. If you're past that, might want to think about a new one with the new pump.

And since the drive belt is off.....the tensioner & both idlers are 120-130k...easy to get to with the front and the drive belt off.

You'll be removing the lower rad hose....how old is it?
Since you'll have it off (and the coolant drained), might want to think 'bout new upper/lower rad hoses.

Coolant drained....how 'bout those T-stats?

And the biggie....that 4" piece of (3/8?) hose on the diverter tube...a must do with the front end off.

4' long 3/4" breaker bar, got one of those layin' 'round?
:wink2:
 

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Discussion Starter #8 (Edited)
So, looked at some other threads - got a list together. Haven't ordered anything yet 'cause not positive it's my water pump at the moment. Will pull the inner fender maybe next weekend and verify.

red RTV
water pump with housing and all O-rings and gaskets.
Lisle flywheel holder and 36 mm socket
40" long 3/4" breaker bar
1/2" to 3/4" adapter (my torque wrench (my big one) is 1/2" drive)
Lisle fan clutch wrench
silicone grease for O-rings
Dexcool
I'll deal with the short "heater hose" when I get it off by running up to the parts store.
I also added a kit of body clips - needed these anyway as I have a couple of broken ones and a few missing. $9 for qty 200 of 6 different sizes - how can you go wrong?

I've fairly recently replaced the tensioner and both idler pulleys and they are just not hard to get to at any time. The belt has 10k miles on it (I replace every 100k).

Hoses and T-stats are ~ 1 year or so old.

I've been on a "replace everything rubber campaign" for a while now.
 

LHN...We ARE the Joneses
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If it is the WP, it's not like it's a rushed issue...you could drive for months and it might only leak a bit here and there. Plenty of time to gather all of the goodies.

How long has it been since you cleaned the coil stack?

If the coolant is drained and the rad is pulled out (to thoroughly clean all of the coils and in between)....there's enough room for an impact wrench to fit and not damage the rad fins, vs the breaker bar. Something to consider.
 

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Discussion Starter #10
Funny you mention that. This one seems to only leak when the system is pressurized (hot) and not much even then but the first one went out on the highway and when it went, it was GONE! I left it at a dealer in Chattanooga, TN, got a rental and kept going. Picked it up on the way back.

I think it was ~June '19 that I cleaned the cooling stack.
 

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Yours IS 'kinda' odd, in that the common trail of long mileage owners, only once do they replace the OE water pump, and then whatever they choose, rebuilt, new, half a pump, whatever.....it's the last WP they ever have to replace.

Makes ya wonder if GM had a built in fail point JUST after the 100k mileage warranty is up. 'cause that's where it always hits, 100-150k.

So, there's that. But I don't know of any other coolant routing/source that would show a leak where yours is pictured.
Sorry.

But it could very well limp along for another year. :howdy
 

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Weld the gear to the shaft that it spins on. Cheap insurance to insure the gear doesn鈥檛 spin off of the shaft when turning high RPMs. 3 tac welds with a wire feed would probably suffice. Use gasket sealer and a metal gasket on the drivers side tube into the water pump. This gasket is held on by 2 nuts and studs, you will know which one im talking about because it is a b**** to get to. Anyways use gasket sealer on it and let it sit before starting the motor after. If this doesn鈥檛 seal correctly you鈥檒l be repeating the whole process until it does


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Discussion Starter #13
Yours IS 'kinda' odd, in that the common trail of long mileage owners, only once do they replace the OE water pump, and then whatever they choose, rebuilt, new, half a pump, whatever.....it's the last WP they ever have to replace.

Makes ya wonder if GM had a built in fail point JUST after the 100k mileage warranty is up. 'cause that's where it always hits, 100-150k.

So, there's that. But I don't know of any other coolant routing/source that would show a leak where yours is pictured.
Sorry.

But it could very well limp along for another year. :howdy


Wouldn't you know - it hasn't leaked a drop (that I've seen) since I started this thread. It was never leaking much - just a small damp spot under the front after sitting overnight. Now, it's not even doing that LOL. It sits a lot for the past 2 years as I started working from home a lot. It may sit for 5-8 days at a time lately. Maybe all that sitting had something to do with the leak. Who knows?
 

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Wouldn't you know - it hasn't leaked a drop (that I've seen) since I started this thread. It was never leaking much - just a small damp spot under the front after sitting overnight. Now, it's not even doing that LOL. It sits a lot for the past 2 years as I started working from home a lot. It may sit for 5-8 days at a time lately. Maybe all that sitting had something to do with the leak. Who knows?


Maybe just order everything you need to do the job so that you have the stuff sitting in the shop. Then if it does decide to let loose one day you are prepared. Its a relatively quick job (not fun) given that you already have the tools and materials for it


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