# Question about 2004 Chevy 2500HD, differential and fan clutch



## farmboy52787 (Mar 22, 2007)

Hi I own a 2004 Chevy 2500HD LS, it does not have a locking differential. My 2006 Chevy 3500 SRW Worktruck does have a locking differential and it helps alot when plowing snow. What would I need to do in order for my 2004 to have a locking differential? Approximately how much of a cost is that?

Also I run a Fisher 8.5' Xtreme V on the 2004 and a few times last winter the truck temperature would go over 210 degrees and a few times would go into limp mode, so we would shut it off, let it cool then it would run fine again. I have heard there is a heavier duty fan clutch that can be put in? Maybe fan clutch isnt the right term, but if anyone knows what I am talking about, please let me know. My 2006 has never overheated. Also I did notice that if you lower the blade some when traveling, it did seem to help and keep the truck at 210 degrees because more air could flow through. Thank you in advance for your replies


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## hosenfeffer (Nov 23, 2008)

when replacing water pump on my 02 there was an issue with fan clutch and warrantees. replaced clutch at same time for said warranty issue per my parts guy. someone with actual gm experience hopefully has answer.


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## Cosmic Charlie (Feb 1, 2009)

Radiator Fan Clutch can have an intermittent failure, just like yours did mine did too ...

Just replace with the HD 2500 newer replacement offered by GM, and you be able to drive on the highway with blade attached without overheating , too. Do not replace with a 1500 fan clutch, get the RIGHT on, do a search here, plenty of threads with the part number ...

My 04 HD 2500 does not have a posi rear end, and plows just fine, basically the single rear tire won't spin unless a front tire also spins, which USUALLY does not occur. and with posi and pushing some snow weight, the rear tires will have more of a tendency to walk sideway, thought not a big deal either ... I do not miss posi when plowing, though my new truck has it ...


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## farmboy52787 (Mar 22, 2007)

Thanks Cosmic Charlie for the info. 
Another question, when you say a truck has a posi rear end that means it does have an automatic locking differential? Thanks


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## Cosmic Charlie (Feb 1, 2009)

old term was posi, -trac rear end, today called Locking Rear Differential

most dealers gave a warranty claim of the radiator cooling fan clutch if you were in the 3 years / 36 month bumper to bumper window ...

replacing the rear differential guts from single track to "locking", my guess $ 500- $1000 (+-), or just replace the entire rear axle and differential assembly, though single track with 4 wd works really good overall, and a locking rear end is better. I would just stay with single track.

talk to the guys that install plows for their opinion, many single track 4 wd trucks plowing without issues ...


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## 2004chevy2500hd (Dec 19, 2010)

here ya' go - I've attached a thread and pdf that I rec'd from my local dealership on the 2500 fan clutches...

http://www.plowsite.com/showpost.php?p=1194310&postcount=10

pdf download:
www.phastinc.com/plowsite/chevy_notice.pdf


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## farmboy52787 (Mar 22, 2007)

Thank you for your replies, I will definitely get this fixed before winter comes.

Also where would I go to get a quote about a rear end? Will a chevy dealership typically do something like this or would this be someplace that upgrades trucks? Thanks


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## JD822 (Aug 4, 2011)

farmboy52787;1299777 said:


> Hi I own a 2004 Chevy 2500HD LS, it does not have a locking differential. My 2006 Chevy 3500 SRW Worktruck does have a locking differential and it helps alot when plowing snow. What would I need to do in order for my 2004 to have a locking differential? Approximately how much of a cost is that?
> 
> Also I run a Fisher 8.5' Xtreme V on the 2004 and a few times last winter the truck temperature would go over 210 degrees and a few times would go into limp mode, so we would shut it off, let it cool then it would run fine again. I have heard there is a heavier duty fan clutch that can be put in? Maybe fan clutch isnt the right term, but if anyone knows what I am talking about, please let me know. My 2006 has never overheated. Also I did notice that if you lower the blade some when traveling, it did seem to help and keep the truck at 210 degrees because more air could flow through. Thank you in advance for your replies


You can add a locking diff in two manners. First would be to buy one from an auto parts store or from an online retailer. The amount of them are from around $470 to $1,100. GM uses Eaton Lockers. You need to know what spline axles you have usually. Then you have to install it or pay someone to do it. This entails removing the rear tires, diff cover, then axles to access the open diff. Reverse procedures. Here is where to get them at: http://www.4wheelparts.com/Drivetra...d-Differentials.aspx?t_c=12&t_s=237&t_pt=5589. Second way is to go to the dealer and pay a ****load for them to put it in. payup Open diffs work just fine when in 4 x 4, but a locker is nice to have, just can get into more trouble. :laughing:

Another to resolve the over heating issue is to eliminate the fan and fan clutch and install an electric fan kit. It not only eliminates overheating AND air flow issues with the blade on, but also increases HP & Trq. due to less rotating mass thus improving MPG. You can buy those @ 4Wheel also. http://www.4wheelparts.com/Towing/Electric-Cooling-Fan.aspx?t_c=67&t_s=422&t_pt=3812


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## JD822 (Aug 4, 2011)

farmboy52787;1300862 said:


> Thank you for your replies, I will definitely get this fixed before winter comes.
> 
> Also where would I go to get a quote about a rear end? Will a chevy dealership typically do something like this or would this be someplace that upgrades trucks? Thanks


The dealer will make you payup. Go to a junkyard and get one with a locker. But imo I would just buy a locker and install it.


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## m.$terner (Feb 28, 2010)

Lockers are nice but I really dont think there necessary. There more for racing in my opinion or anytime your really going to throw a lot of power to your wheels and need both to hook up.Now they are a nice accessory in a truck but with a good ballast in your truck ,not having a locker is no big deal when plowing snow.Save your money imo


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## Cosmic Charlie (Feb 1, 2009)

m.$terner;1302530 said:


> Lockers are nice but I really dont think there necessary. There more for racing in my opinion or anytime your really going to throw a lot of power to your wheels and need both to hook up.Now they are a nice accessory in a truck but with a good ballast in your truck ,not having a locker is no big deal when plowing snow.Save your money imo


I agree

and that is why the dealer's don't order every new plow truck with a locker differential ... so truck owner's actually DON'T prefer it, though most do ...


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