Tim@DOA

Merchant sells this upgrade for 250.00, another issue is the ATF used for lubricating the case, and the amount. 5-30 synthetic engine oil is now the recommended lube, and, 2.75 qts. is the amount, necessitating the case to be filled from the speed sensor hole. There's an excellent write up on the woes of the case, easily corrected, on the diesel page, including the need for better lube. I'll agree that it's B.S. when GM knows about mortal issues, and considers them to be a fusible links to aquire work for service depts. Again though, it's not just GM........................

HayJay

The part is $250 and if you have Merchant install it, will be just under $500 total, including the part. This whole upgrade thing is more of a preventative deal than a repair. If you find a hole in your case, not only will you need the upgrade but you'll need a new case half as well. A far as your noise issue, unless you have a bunch of fluid all over the bottom of your truck, my guess is you may have other problems.

HayJay

I've read that too and I mentioned it to Merchant when he was working on my truck. He said he hasn't seen any reason to use oil. Just plain old ATF, filling it to the recommended level and changing it about once a year, is all that's necessary.

I've heard of lot's of people using a mix of the two, or this that and the other thing. Straight ATF for me. To each his own I guess.

Biggus

iTrader: (1)

Thought I'd bring this thread TTT.

Just lost four wheel drive on my 2500 HD, Dealer said very low on fluid, took 2 quarts, leak at rear seal. Had the truck serviced and everything was fine before I drove to Key West and back (4000 miles)

I read that this problem has no effect on 4X4, will running the transfer case low hamper the 4X4 engagement?

Thanks,

Kurt

HayJay

The t-case only holds about 2 quarts, so if it needed 2, you were basically dry. With little or no fluid in the case, certainly my guess is that it would have trouble engaging in 4-wheel drive.

The pump rub issue is different from a rear seal leak. I had the pump upgrade done to avoid the rub problem, but I personally am still dealing with an output shaft (rear seal) leak that doesn't seem to want to go away.

I've replaced my seal once now and it is still leaking from the rear somewhere. To be honest, I'm not sure if I replace the seal again if that will fix it. I may have to take it back to Merchant and see what he thinks. Again, this has nothing to do with the pump rub problem or with the upgrade that I had him install. I've heard of many people having trouble with the output shaft seal leaking on these trucks and it sounds like you and I are just part of that group.

As far as the pump rub thing goes, if the pump is rubbing the case housing, using 4-wheel drive does not help or hurt the problem. It is always rubbing as long as you are driving, 2 or 4 wheel drive. Over time, it will wear a small hole in the case and the fluid will quickly leak out and leave the case dry. From what you said it sounds like you had a leaky output shaft seal and it ran itself dry. Same ending result, it just leaked from a different spot.

Just noticed your other post, that your case is junk. Give Merchant Automotive a call. Here's their website: http://www.gmdieseltech.com/store2/

He can sell you a new case and install the pump upgrade in it as well. Don't buy one from the dealer. You'll just be right back where you started.

articfriends

iTrader: (1)

The chevy dealers now have a upgrade part to put in the t-cases,Idon't know what they are doing to brand new ones or ones that go up in smoke,there are several aftermarket vendors (besides merchant) out with fixes for the pump rub problem too,Smitty

HayJay

Really? That's the first I've heard of that.

JMAASKE

Been out since April 2007 Here you go.....





Subject: Improved Oil Fluid Wear Pump Clip - keywords 136 149 246 246EAU 261 263 263EAU housing leak case transfer transfercase #PIP4118 - (04/17/2007)



Models: 1998-2007 Light Duty Trucks and Utilities

Equipped with New Venture Gear Transfer Cases RPO NP1, NP2, NP3, NP4, NP8




--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Oil pump wear clip P/N 12470559 is broken or out of position. This may cause the pump to wear a pin hole in the transfer case rear half. If the wear is severe the transfer case may be damaged due to lack of lubrication. The clip may fatigue and break. The clip may become loose and shift out of position.

Recommendation/Instructions:
A new clip design has been released. P/N 89059653 is available for both production and service. This new part totally cancels and supersedes the former P/N 12470559. Only the new clip will be available.

This new oil pump wear clip should be used whenever a transfer case is opened for any type of internal service. See photo. GMSPO currently has inventory of the new part.





Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

HayJay

Nice of them to do something so quickly, isn't it?

turnerrd

Not sure if my problem ties into this but my 05' 2500 HD Dmax had the T case go out of it back in July of 06'. Had approx 100K on it. It all started when I had the fluid change at approx 65K-70K miles. It's a fleet vehicle so it get got done at a Valvoline oil change store and got filled with Dexron III (ATF). At every oil change (5K) they would check it and it was progressivly getting dark and burnt looking. At about 80K I was getting it flushed and changed close to every other time because it was burn't so bad. Finally going up the road one day it started making a faint grinding noise. Pulled over and tried to shift it a few times into 4hi, 4lo. Wouldn't do it at first then it finally went in. No problems rest of the day. Pulled the boat that weekend no problems. Took it to GM Monday, called back and said clutch plates had let go sent metal through the whole case, it was junk. Reman $2,400 later. I looked at the owners manual and it called out for the GM synthetic. Dealer looked into it as I was hell bent on hanging this one on the Valvoline quicky shop, but they came back and said no that Dextron III was approved. Then why would the manual call out for synthetic, WTF? I kind of just let it go since it didn't come out of my pocket. I'm starting to wonder now if the metal wasn't the tabs breaking off the oil pump wear clip?
Drove it another 50 K and got the same truck 07' (classic). 76K so far and no prob. I had GM change the fluid at 50K this time and made sure they put synthetic in.
Since this truck has a 100K powertrain warranty on it will GM go ahead and install their the new oil pump wear climp under warranty even though I'm not having any problems yet?