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Redline MT-90


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Hi Ya'll.I just changed my transmission fluid.I did it before 2 years ago.I used the same fluid as last time.Redline MT-90.It  took about 2 quarts,I put teflon tape on the drain plug and fill plug.My Transmission is only a few years old.I used a pump from Harbor Freight.What I did was,got a mobil one quart oil container since it has the big opening,and the pump fits in it,and the end part of the pump on the hose clips in the filler hole in the transmission and stays put.The pump is only 8.95.I have no trouble using synthetic oil.No leaks.No particles was in the fluid,don't ever grind the gears.Transmission is so smooth.https://www.harborfreight.com/gear-oil-and-fluid-pump-61746.html.

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I suspect Redline, Royal Purple and a few other brand names use the same synthetic base stock as the General Motors Delco 'Friction Modified Synchromesh Transmission Oil that I like. All they do is add a colorant package. I tried to buy some last year and unavailable from the GM dealer. I asked what was in the new Camaro and Corvettes. They said it was a special ATF and at $25 a liter, not cheap. 

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Did a little research and I suspect Mike's suspicion may be correct. All synthetic tranny oils are made with a POLY-ALPHA-OLEFINS (PAO) base, but that's a polymer of 6 different alfa-olefins and other monomers. It's not inconceivable there could be differences in their blends, but there's only a few manufacturers of this expensive crap alternative. If they're US brands, chances are they're all made by Chevron-Phillips. Japanese brands are either Idemitsu, or Mitsui Chemicals, and European stuff would be Rextac.

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Half of their advantage is that they are so thin compared to 80w90 gear oil. Synchros push the thin stuff out of the way easier and I found gear changes were faster with the same effort as before with the thicker stuff. Some FWD cars use engine oil. My sons '90s Grand Am did (5w30 synthetic) but not sure if engine and 5 speed were sharing the oil, I think it was, or just using the same oil

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Tranny sharing oil with the engine sound like a recipe for disaster. I'll bet they both took the same oil. I had a 73 VW bus with a 2.0L 914 engine that felt like it was on it's last leg, so against all advice I put full synth in it as a Hail Mary. It ran noticeably smoother, 10-15 degrees cooler, and continued for another 6k miles before losing a valve seat. And no, please don't say it lost the seat because I put Synth in it... ;o)

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It did sound like a bad idea. Engines have the same lubricating needs for metal on metal, gears and bearings. It was a 2.5 liter 4 cylinder, popular with GM in the 90s. Probably he meant that they both use the same oil, but it does use engine oil..

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The oil 'weight' is measured differently I think. 90 weight is about the same as 40 weight engine oil.

 

I am curious about the GM ATF oil used in the Camaro/Corvette manual transmissions.

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50 minutes ago, datzenmike said:

I am curious about the GM ATF oil used in the Camaro/Corvette manual transmissions.

 

Yeah, I'm kinda a curious about that myself. It's more than a little weird that GM would us a Gov regulatory agency oil for their prestige models. Time for some more research...

 

Okay, I'm backing out of the thread now, but snickering.

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I had a crash course in ATF a while back. Can't remember the specifics, but when I asked my auto trans rebuilder about the differences, he said that older ATF, ie- Dexron III and earlier, plus Mercon and some others, have a high gear oil content and are non-synthetic. Newer ATF is usually full synthetic can contains less gear oil. When I made a mistake and half-filled a new trans with older fluid, he said it wouldn't really matter.

 

Also, for what it's worth, my Dodge Ram uses ATF in the power steering system, but Dodge relabels the ATF with a special power steering brand name, and it's literally identical. They are just trying to have you stock your shelves with both ATF and PS fluid.

 

In a nutshell, branding and labeling of ATF is probably similar to inexpensive central CA wines, which are blended from the same stock in massive tanks and sold off to wineries for finishing.

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On 9/4/2021 at 9:12 AM, Thomas Perkins said:

Hi Ya'll.I just changed my transmission fluid.I did it before 2 years ago. .

 

Regular dinosaur oil is good for 30K or 5 years. Synthetic probably longer.

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How long does Redline transmission fluid last?
 
 
At 220 degrees, which is commonly encountered in many transmissions, the fluid is only good for about 25,000 miles. At 240 degrees F., the fluid won't go much over 10,000 miles. Add another 20 degrees, and life expectancy drops to 5,000 miles.I recently changed my Redline MT-90 Transmission fluid and it was worn out,I put it in 2 years ago and put 11,000 miles on it..I had the transmission installed 4 years ago,but it didn't have Mt-90.The guy that put the transmission in told me to change it every 2 years and use synthetic.I've had my 720 for 27 years,got 375,000 miles on the speedo.Bought it in 94 with 108,000 miles which means I have kept it running.Now I kinda just work and come home,now only drive almost 6,000 miles a year.The gears change real smooth.For some reason,he didn't use teflon tape on the drain plug and it was having a slow drip,in which i did have to add fluid.Since I have used teflon tape,it no longer leaks.Mike, you did tell me once not to use synthetic oil in the motor.I used it before you told me,and I went back to regular oil.I have a Jasper remanufactured engine,got it in 2009,now have 90,000 miles on it.
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 If this is true then switch back to 80w90 gear oil as the change interval is 30K or 5 years.

 

 

Synthetic has to be better and it's not affected by heat and why it's used in turbo engines and run at 300F to 350F.

 

 

 

It's just that synthetic tends to leak on older engines, a new one with new seals would be ok but really? does anyone need that much protection? Mobile one says up to 20,000 miles between oil changes. There aren't too many engines that would go 3,000 miles on a quart of oil so by the time you get to 20,000 miles you will have put almost 7 quarts in, replacing all the oil almost two times. Basically you never have to change the oil because it's still new. If you went 5,000 miles per quart (wildly optimistic, I would dare to say impossible on a Datsun) that's 4 new quarts by 20,000 miles. Enough for an oil change. Synthetic is incredibly expensive too.  

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