96 4L60E Too Flush or Not

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df2x4

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DEX III Has been obsolete for years. I believe in 2005 maybe 06, there was a service bulletin that states DEXIII is out and DEXVI is in! for various reason but mainly because DEXVI is a far superior fluid that helps repair the soft parts inside... friction modifiers. the service bulletin was strictly for the fluid and the vehicles that use it. Therefore I personally believe it is also used in TCases... and has been in mine for years.

Al

There was a GM TSB which stated not to use Dexron 6 in certain applications that called for Dexron 3. Specifically transfer cases, manual transmissions and power steering systems. @MIHELA explains it well in the quote below. He and others also mentioned in another thread that the different viscosity between Dex 3 and 6 is probably the reason for this.

GM specifically said not to in a bulletin. That's why they kept "Manual transmission and transfer case fluid" which was Dexron III under a different name. Technically they couldn't call it Dexron III because they stopped certifying that spec but its the same.

Edit: the bulletin is #04-07-30-037D. The notes about manual transfer cases are towards the bottom of the first page:
"The content of this bulletin does not apply to manual transmissions or transfer cases. Any
vehicle that previously required DEXRON®-III for a manual transmission or transfer case
should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case
Fluid. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid."

That said, I've had Dexron 6 in the transfer case of my Suburban for a few years now and I haven't observed any negative effects. I found out about that TSB after I'd already replaced the fluid with Dex 6. I bought some of the GM recommended 88861800 fluid mentioned above with the intention of replacing it after I found out, but haven't done it yet. So far, so good.
 

thegawd

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I think that service bulletin also states which xfercases aswell. I have a 243c in my burb. when I first removed and replaced the 4l60e in my burb I noticed a spot which seemingly allows fluid through from the xfer case to the tranny. I may be wrong but when I picked up the tcase to move it, I held it up on my chest and fluid poured out and all over me when I didnt think it could get through.... I dont for sure though.

but ya your right about that bulletin, I forgot about it as I dont think it applies to the 243C. I'd have to view that bulletin to know for sure. that said. I used it during my r&r and i believe the shop who did the rebuild did as well because we talked about the fluid and he didnt mention the tcase fluid just what fluid was used.

Al
 

df2x4

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but ya your right about that bulletin, I forgot about it as I dont think it applies to the 243C.

I believe it does apply to the NP243s as they originally called for Dexron 3, but like I said I haven't noticed any negative effects of running Dexron 6 so far. I have a 243 in my 'burb as well.

I think the only GMT400 transfer case the TSB wouldn't technically apply to would be the NP246 that takes the AutoTrac fluid.
 

thegawd

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interesting. ya maybe I dont know what I'm talking about... all the time. lol. I swear I read a more in depth service bulletin that was more than just a small paragraph that says, "does not apply to manual transmissions or transfercase..." but I cant find it right now. what funny is the next paragraph begins with..., "consult the owners manual or service information for fluid recommendations." LMAO confusing the matter even more. lol.

I think I will call the shop who did my rebuild and ask them what they put in.

have a good night guys!

Al
 

alpinecrick

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I'm a DexIII guy myself, at least in these older transmissions.
Like a lot of lubricants, even Dex III is better than it was originally. The additives that went into ATF 25 years ago are obsolete and replaced with mo’ better additives.

The Valvoline full synthetic ATF we can buy at WalMart is suitable for Dex VI transmissions.
Keeping the fluid fresh and bright red is important as anything we can do to prolong the life of the trans….
 

Caman96

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Geeezuz, how big of a bump did you hit………?

I have TWO O-fficial GM magnets in each my trans pans…….

So there….:)
This what magnet looked like when I peeled it off pressure manifold switch. Picture is from today, debris you see in pan wasn’t there but that’s pretty much what magnet looked like. So far so good with new fluid. Do you think if anything bad, would’ve happened by now?
You must be registered for see images attach
 

Caman96

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I’m not sure how that magnet got there. I didn’t hit a bump(of notice)! Got the truck last summer with 46k. Had a local mechanic drop the pan and change filter. At that time he called and said there’s no magnet in pan. So I brought him one and he buttoned it up. Couple weeks ago when I was replacing pan with new aluminum pan is when I saw the magnet on pressure manifold switch. Almost the first thing I saw when I dropped the pan. Oh well, still running good. Another thing I did for new aluminum pan since you can’t just stick a magnet inside was to get new magnetic drain in plug. And then stuck a few small powerful magnets to the plug itself on the outside. I tested this before installing and it really improved the strength of magnetism!:ryu-cvs-hadoken-a:
 
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