# To change or not to change fluids?



## CK82 (Sep 17, 2005)

I was wondering if any of you mechanics out there would recommend having the differentianl fluid changed after a year of summer wear and tear and winter of snow removal?? 

Also what about trans fluid and the front end differential??

Anything else you recommend being done yearly that is important??

Thanks


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## SnoFarmer (Oct 15, 2004)

Yes, tranny,T-case and diffs every year, it's cheep insurance


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## dodgeguy99 (Apr 18, 2006)

every year, oil and grease is cheap but parts aint


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## TTBoy77 (Nov 21, 2006)

I would....a couple hours and a couple dollars versus a couple days and a couple thousand makes sense to me. purplebou


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## Gmgbo (Jan 18, 2005)

IF you change the fluid in the tranny in your 95 chevy you can kiss it bye bye. From what ive seen if you dont change the tranny fluid every 10-20k miles u might as well not change it all.


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## scottL (Dec 7, 2002)

every spring; Power flush radiator and trans. Change diff's every 18 months. Truck keeps on going and going.


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## AbsoluteH&L (Jan 5, 2006)

Gmgbo;386958 said:


> IF you change the fluid in the tranny in your 95 chevy you can kiss it bye bye. From what ive seen if you dont change the tranny fluid every 10-20k miles u might as well not change it all.


I have heard this too, of most trannys, regardless of make. So is it better to let it run till it pops if it already has high mileage and no changes from prior owners


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## SnoFarmer (Oct 15, 2004)

Yea! what ever you do don't get rid of that burnt fluid or put a clean filter in that tranny. I mean all the stuff like worn bands, clutch material and water are good for it. Why would you want to drop the pan and adjust the bands?? 

I didn't say have a shop powerflush it, what good does that do?


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## AbsoluteH&L (Jan 5, 2006)

Let me ask this again. Now read slow so you don't get lost. I have heard that changing tranny fluid in high mileage trucks is bad for the tranny.I have also heard of to many people changing fluid on a high mileage tranny only to have it go within the next few months.By the way who said the fluid was burnt?!


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## Yaz (Apr 13, 2005)

AbsoluteH&L;387497 said:


> Let me ask this again. Now read slow so you don't get lost. I have heard that changing tranny fluid in high mileage trucks is bad for the tranny.I have also heard of to many people changing fluid on a high mileage tranny only to have it go within the next few months.By the way who said the fluid was burnt?!


First off on a plow truck if you afford the cheep insurance, I say change it at least every other year depending on how may miles the truck does or how hard it works. I run Mobil 1 in the front and rear diff and synthetic ATF in the transfer case and trany. If you have over 75K, I say don't flush it completely at most a drain and fill. Taking a truck in with over 100K and doing a flush will clean out the varnish out of the valves and there is a 50% chance it will not shift right in few months if not a shorter time.. I have see this happen and friends that are full time mechanics all agree this happens all the time.


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## SnoFarmer (Oct 15, 2004)

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AbsoluteH&L;387497 said:


> Let me ask this again. Now read slow so you don't get lost. I have heard that changing tranny fluid in high mileage trucks is bad for the tranny.I have also heard of to many people changing fluid on a high mileage tranny only to have it go within the next few months.By the way who said the fluid was burnt?!


Well lets see were you the first post, no, ck82 was then you added your input.
typing slow for you as you are lost in your own mind

Changing the filter and fluid IS ALWAYS A GOOD IDEA........

It is power flushing that causes problems in older trannys.....

Plus how do you know that(ck82) his fluid is not burnt. (I'm not saying it is)

Typing slowly for you H&L, I was giving examples of why it is a good idea to do this preventive maintenance EVERY YEAR regardless if mileage as plowing is an extreme environment for running gear.prsport


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## derekbroerse (Mar 6, 2004)

My ex had an '86 Olds Delta 88 that shifted kinda crummy (late and lazy)and hadn't been changed by the previous owners, so I did a fluid and filter change on it, tranny died within about two weeks--slipped to the point of being undriveable.

My working theory was that maybe a certain amount of the worn off friction material was suspended in the fluid and was magically allowing the plates to grab still, and once we changed to clean fluid that was it.

Others on here have reported the same thing.

Its not like its any kind of a scientific test with proof though, but I wouldn't be suprised either way.


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## SnoFarmer (Oct 15, 2004)

derekbroerse;387768 said:


> My ex had an '86 Olds Delta 88 that shifted kinda crummy (late and lazy)and hadn't been changed by the previous owners, so I did a fluid and filter change on it, tranny died within about two weeks--slipped to the point of being undriveable.
> 
> Others on here have reported the same thing.
> 
> .


Just using your post as an example.

There are a few that blame the draining of the fluid and a new filter as the demise of there tranny.
They think that if they had left it alone it would have lasted forever. 
Most of these people waited until there was a problem. 
Then they had the tranny fluid changed.

A new filter and fluid will not fix the tranny. 
It's called preventive maintenance.


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## derekbroerse (Mar 6, 2004)

SnoFarmer;387771 said:


> Just using your post as an example.
> 
> There are a few that blame the draining of the fluid and a new filter as the demise of there tranny.
> They think that if they had left it alone it would have lasted forever.
> ...


I would say that it WAS the demise of the tranny. It didn't slip before the fluid change, just had a bit of a mind of its own. It definately DID slip afterwards. Last forever, no. But more than two weeks, yes. Was kicking myself and wishing I'd left well-enough alone.

Fluid and filter CAN fix certain issues, especially if the passageways are blocked up with crud and starving the system, or the fluid has lost some of its qualities thru overheating. No it won't make friction material magically reappear on the plates.

Preventitive maintenance should have been done by the previous owners. We'd only had it for a few monthes at that point and it was on my to-do list.


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## CK82 (Sep 17, 2005)

Any idea about how much a rear differential fluid change w/ filter would cost?
Stupid question, but what does the transfer case do exactly? How often should this be change? 

The front and rears diff's have been changed last year, and I think it had been maintained somewhat well before I purchased it two years ago.I just work my truck pretty hard all year round and like you said would rather be safe than sorry. My front diff. got shredded this year and had to be replaced, not sure what caused it, mechanic said might have been the actuator not engaging.


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## derekbroerse (Mar 6, 2004)

CK82;387944 said:


> Any idea about how much a rear differential fluid change w/ filter would cost?
> Stupid question, but what does the transfer case do exactly? How often should this be change?
> 
> The front and rears diff's have been changed last year, and I think it had been maintained somewhat well before I purchased it two years ago.I just work my truck pretty hard all year round and like you said would rather be safe than sorry. My front diff. got shredded this year and had to be replaced, not sure what caused it, mechanic said might have been the actuator not engaging.


Differentials don't have a filter. Some have a magnet inside to catch metallic filings, which needs to be wiped off during a fluid change. It is an easy job on a hoist for a mechanic, if it cost more than an hours labour I would be shocked.

The transfer case is nothing but a gearbox that divides the power between the front and rear wheels. Most use the same oil as the differentials. I'd say do them all at the same time.


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## Yaz (Apr 13, 2005)

Your rear diff in your truck will hold almost 4 quarts, no filter inside. The cover does not have to come off because you have two plugs- drain and fill. fill to just under the fill hole. you'll need a funnel and a long tube. Be careful the old fluid will stink! lol

The plug has magnet, so just clean it off be fore inserting it back. If you have the Eaton posi, no additive is required. I would go synthetic at around $25-30 bucks at a auto parts store.

The transfer case takes a few quarts of ATF. Same dreal..drain and re-fill to just under the top hole.

Whats it do..It transfers the power at the output of the trany back toward the front differential.


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## Yaz (Apr 13, 2005)

derekbroerse;387949 said:


> Differentials don't have a filter. Some have a magnet inside to catch metallic filings, which needs to be wiped off during a fluid change. It is an easy job on a hoist for a mechanic, if it cost more than an hours labour I would be shocked.
> 
> The transfer case is nothing but a gearbox that divides the power between the front and rear wheels. Most use the same oil as the differentials. I'd say do them all at the same time.


Derek you beat me to it.. PS. His truck used ATF in the tranfer case not gear oil.


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## B&B (Nov 4, 2006)

Yaz;387952 said:


> The cover does not have to come off because you have two plugs- drain and fill. fill to just .


 If he's referring to the '95 and not the '06 in his sig, then it will have to come off to drain it as the 9.5 14 bolts dont have a drain plug. Sure would be convenient if they did though  .


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## Yaz (Apr 13, 2005)

B&B;387979 said:


> If he's referring to the '95 and not the '06 in his sig, then it will have to come off to drain it as the 9.5 14 bolts dont have a drain plug. Sure would be convenient if they did though  .


Opps My bad...You absolutly correct.. I wasn't thinking strait.

He also would need a a gasket for the cover as well. And the magnet is inside the cover.


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## CK82 (Sep 17, 2005)

Yea I was referring to the 95 Chevy. I remember a charge for a gasket on the rear diff. Would you recommend having the transfer case fluid changed as regularly or along with the diffferentials?


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## B&B (Nov 4, 2006)

CK82;388026 said:


> Would you recommend having the transfer case fluid changed as regularly or along with the diffferentials?


Absolutely. I look at it this way, preventative maintenance is cheap insurance.


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## CK82 (Sep 17, 2005)

Thanks for the replys! My dad was in the car business for ever and knows alot but he's getting older and doesnt have time anymore, so I'm doing my best to learn what I can. I do most of my maintanence on my equipment and would like to sometime be able maintain my trucks fully.


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## CK82 (Sep 17, 2005)

Hey one other thing, I cranked my torsion bar to help out the sag in my front end while having my huge plow on! It helped alot and I dont seem to have any unusual wear on my tires or pulling while driving. Would you guys suggest backing the torsion for the summertime or just leaving it alone??


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## dodgeguy99 (Apr 18, 2006)

i would just leave it alone


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## B&B (Nov 4, 2006)

CK82;388805 said:


> Would you guys suggest backing the torsion for the summertime or just leaving it alone??


It's not a bad idea to turn them back down some as it can help your front end components last a little longer depending on how much you turned them up to begine with. If you had to crank the heck out of them then yes, I'd turn them down some for the summer months but if you didn't go much more than about 3 turns from the factory setting then I wouldn't worry about it.


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## Yaz (Apr 13, 2005)

CK82;388805 said:


> Hey one other thing, I cranked my torsion bar to help out the sag in my front end while having my huge plow on! It helped alot and I dont seem to have any unusual wear on my tires or pulling while driving. Would you guys suggest backing the torsion for the summertime or just leaving it alone??


Be fore I answer you...How much did you turn them?
# of turns

Besides add some Timbrins for a 150 bucks, well worth it. Helps handle the weight (less sag) and you don't have to crank and de-crank if you going up a lot to compensated. Cranking too high can over extend your shocks, wear tires funny, wear front end parts faster and make the ride hard.


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## mr_udy (Feb 26, 2006)

derekbroerse;387768 said:


> My ex had an '86 Olds Delta 88 that shifted kinda crummy (late and lazy)and hadn't been changed by the previous owners, so I did a fluid and filter change on it, tranny died within about two weeks--slipped to the point of being undriveable.
> 
> My working theory was that maybe a certain amount of the worn off friction material was suspended in the fluid and was magically allowing the plates to grab still, and once we changed to clean fluid that was it.
> 
> ...


Exact same thing on our '86 Park Ave (damn near same car)....had less than 50K at the time. GM ended up re-imbursing us for 1/2 the cost...this was way back in the late 80s...car was still "new".

I see this debate all the time. I hold to change it often or dont change it at all!

Our Yukon had 80K when we got it...I'm leaving it...its got 110K now and no problems. I just pulled the plug on my Allison and changed the spin-on filter at 38K....got my fingers crossed that I will not have any problems.

I talked to the guy who R&Red my K5 Blazers 4L60...he said if its higher mileage (our Yukon when we got it) and still looks red and smells OK...go ahead and change it. If not, leave it. Even though ours looked/smelled OK, I left it fearing the worst...a $2000 bill that we could not afford at the time.


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## CK82 (Sep 17, 2005)

Yaz,

They were turned quite a few times, not sure the exact number. It does right more stiff, the tires seem fine after 5500 miles. I like the ride more and it sits higher up in the front, but I dont want to damage or wear anything on the front end more than it should. I probably will look into timbrens, are they diff. to install?


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