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jgkurz

Borg Warner T5 recommended fluid????????

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Hi all, What is your experience with ATF or gear oil in the 1983 Borg Warner T-5 transmission? I believe the service manual recommends ATF, but what brands or type should I purchase? I'm a fan of synthetic so I'll probably go that route.

 

I've heard of people running gear oil in the T-5. Is that a better choice?

 

I am on the street 75% of the time and the track 25%.

 

Thanks!

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The Nissan owners manual recommends 80-90 weight gear oil for manual trannies, although there is no mention of a manual different than the Nissan for a turbo model (T5 is not mentioned anywhere). Personally I've used gear oil in mine, and it works fine. I just switched to Redline 75W90NS, and it is good too. IMHO, ATF really SUCKS for lubrication ability, is just way too thin for a gear lubricant. I've also heard the ATF for a T5 is really just for the World Class T5 that has a unique sychronizer that gear lube cannot squeeze in to lubricate.

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I use a sythetic 85W-90. Many may have issues with that but a tranny is a different animal. The syncros like light oil where the gears like heavy oil. The bearings are fickle too, they don't get any oil if the oil is to heavy and if the oil is too light not enough lubricaiton. Just my $0.02. Mike

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The WC T5 has papercone synchros and roller bearings on the speed gears. These tiny rollers need the thin oil for lubrication. They were designed for ATF and work well with it. The non-wc uses brass ring synchros and bushed speed gears. The 80w90 should be fine. Many people run ATF in the older trans, but IME, shifting is smoother with gear lube.

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Guest greimann

This subject surfaces from time to time, and as the self appointed HybridZ tribologist (lubrication professional), I decided to do some research and see if we can put some science and logic to the myth and rumor. Granted that my information comes some from the web and some from transmission rebuilders, but all seem to be credible sources.

 

Known facts:


  • W/C T5's have needle bearings under gears #1, 2, &3.
    Non W/C T5's do not have needle bearings.
    The lubricant required for W/C/ T5's is automatic transmission fluid (ATF).
    W/C T5's were introduced in the 1985 Ford model year and 1987 Chevy model year.
    The most important feature of any lubricating fluid is the viscosity.
    Lubricants are specified to provide the longest service life of the gear box as a system. This includes gears, bearings, synchros and seals. Failure of any one of these components is considered a failure of the entire system.

 

Supported facts through research, expert testimony and sound lubrication principles:


  • The reason that ATF if specified for W/C gear boxes is to ensure a long service life of the needle bearings - the most likely component to cause a system failure.
    The needle bearings have small passages that make them sensitive to lubricant viscosity.
    Small diameter cylindrical rolling elements that operate at high speed need a low viscosity fluid compared with the larger diameter rolling elements such as ball bearings.
    Automotive transmissions rarely fail due to the gear teeth wearing out from improper lubrication. It is usually a bearing failure.

 

Conclusion:


  • Since non W/C T5's did not have needle bearings, it is assumed that they should use API GL 4 or 5 (75W-90 or 85W-90) gear oil.
     
    W/C T5's must use ATF.

 

Sources:


  • My transmission rebuilder guy
http://www.5speeds.com/t5/index.html
http://www.mustanggt.org/gttranny.htm
http://www.moderndriveline.com/Technical_Bits/t5_history.htm

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I drained, what probably was, the original factory transmission gear oil from my 60,000 mile, 82 zxt. The fluid did not appear to be ATF. It appeared to be "normal" gear oil. I replaced it with Redline 75W90NS. My T5 shifts smoothly and is very quiet. I think I made the correct fluid choice.

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I drained, what probably was, the original factory transmission gear oil from my 60,000 mile, 82 zxt. The fluid did not appear to be ATF. It appeared to be "normal" gear oil. I replaced it with Redline 75W90NS. My T5 shifts smoothly and is very quiet. I think I made the correct fluid choice.

 

Thats my choice as well.

 

Yasin

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Well, I think it's been proven over time that gear oil will hold up in these trannys. It's interesting to see the literature tho. I've always run Mobil 1 75-90 synthetic in mine. Not sure I'm about to try the atf since I've had such good luck with mine and the power levels I'm at. Of course, my T-5 is sitting on the ground next to the car now, and the powerlide is sitting on a jack ready to do some fitting in the bellhousing. Anyways, I'd be curious to hear from some guys that have run atf in the T-5.

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I've been running the same World Class T-5 for 2.5 years now. Making 300whp on a dynojet and 255whp on a dynodynamics loaded dyno. When I first put the transmission in I ran ATF for a little and it was always really rough to shift ( I guess the bad synchros and such a thin fluid) I tried Mobil 1 synthetic and since then it has been a lot better.:mrgreen:

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I've run both in some of my T-5's. The ATF seems to work well but, I think I like the feel of the Redline MTL better. I once had a issue with with one of them that it would not shift into 2nd when it was real cold. I changed the fuild from no name brand fluid to the Redline and the proublem was solved.

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