gear_grinder

iTrader: (1)

Hi,

im picking up a t56 with some issues and am going to fix the issue and refresh it with some fresh parts. I know the FSM specifies Dex ATF, but I dont think it has nearly the shock protection or boundary layer lubrication like a gear oil does. i'm thinking about running 3quarts of redline gl4 mt80 and a quart of light weight shock proof. Too thick? you might think so but gear oils are not measured on the same viscosity index. Through my own testing dex atf is about a SAE20 engine oil, where SAE 70-80 gear oil is equal to SAE 20-30 engine oil.

with the anti-wear additives, high pressure lubricants, and shock protection offered by gear oil it seems like a better alternative for abusive transmission conditions

jmd

iTrader: (4)

Dex III or equivalent changed reasonably will put a trans. to 200k no problem with regard to bearings and offer correct shift characteristics. A mid-life bearing pre-load check isn't a bad thing to be honest.

But furiously spanking to posts on bob is the oil guy isn't going to fix anything, nor is the shock protection going to help blockers do their job.

gear_grinder

iTrader: (1)

I dont really know what likes to fail on this transmission via overload. I imagine the output shaft because the the vipers is a larger diameter to last for the cyclic life of the transmission behind a higher torque engine. Don't you think a fluid with added shock protection/cushioning wouldn't be a good idea?

85MikeTPI

iTrader: (9)

https://ls1tech.com/forums/manual-tr...on-theory.html

"hypoid oil" == "gear oil"

You've been warned..

jmd

iTrader: (4)

"If some is good, more must be better" is your fallacy. If something is up to task, changing it's spec. to be higher-rate, heavier, larger, etc. doesn't improve anything.

Under heavy load, lubrication can be an issue in the T56 and circulation to redirect the existing volume is the fix. Thickening the fluid is not.

The Viper had the 30 spline slip yoke by chance because it is a Chrysler standard and as the introductory production T56 vehicle for Borg Warner's new T56, they specified it.

GM specified their 27 spline small output because it was going into 3400lb 1993 F-bodies and kept the slip yoke production variety to a minimum across T5, 4L60 and T56 equipped models. And when they put it into a 5000+lb 6.0L SSR, they specified their 32 spline.

gear_grinder

iTrader: (1)

hypoid oil is gear oil, but gear oil is not necessarily hypoid oil

hypoid refers to the common type of differential found in passenger cars/trucks where the pinion gear is driven ether above or below the center line of the ring gear (I dont remember the reason why right of the top of my head)

The blocker rings friction on the beveled edge of the actual gear to slow them, matching speed, in order to shift would not be dissimilar to a clutch type LSD right? gear oil works fine in there, same wet clutch principle.

The thread you posted seems like other problems were to blame for the not shifting after the gear oil was added, because dex/merc/atf+ contain friction modifiers to reduce the friction coefficient of the wet clutch material to make the transmission shift smoother and give a more "luxurious" feel.

You've probably heard the "type f" transmission fluid "trick" GM trans guys would talk about right? That's because the type F fluid contains no friction modifiers that reduce the friction coefficient of the clutch material making the clutches in the transmission very "grabby" and thus making it shift very hard. Same thing if you do not add friction modifier to a clutch type LSD, it will not be very willing to unlock but will wear out faster.

The fluid experiment in your link was interesting, but their was way too many other factors that could have contaminated the results of that experiment and made it seem like the fluid was to blame.

jmd

iTrader: (4)

One independent variable changing and the problem appearing means the fluid was inferior for purpose.

A pre-loaded clutch pack in a diff. (static in straightline, moving when turning) is not comparable to a floating blocker friction ringset (floats somewhat like disc brake pads.)

The thread he posted has no other independent variables but the fluid, so you may want to check with your personal boogie man as to who or what is on his imaginary list of other problems.

The spanking isn't going to be well-fueled here; it's simply known the ATF derived fluids work and others don't by those with miles and builds under their belts. Posting until you're blue in the face about how eking out a better numeric value of shock protection is paramount to one-upping your BITOG peers isn't going to change the facts of decades of use of the Borg-Warner passenger car derivative units.

Out.

BALLSS

OP

Just run 4 qts of Redline D4 if you want to use their product in your T56 if it is newer than 1999 or has had the paper syncro blocker rings swaped to the carbon fiber ones (Tremec started in 99 with carbon)

if older paper ones, use DEX 3

1 FMF

iTrader: (1)

you don't need to do your own testing. it's published information.

your comparison of atf to gear oil and motor oil is not quite accurate. when you compare viscosity of lubricants you need to reference temperature. That's like comparing torque output of engines without referencing the rpm it happens at.

the t56 isn't going to run much hotter than 150°F in the summer time, I know I have a temp sender in mine. on a 200 mile highway trip in 80° F weather it ran at most 163° F. Unless you run lemans or the autobahn, you will simply never have a problem with temperature and the viscosity of atf or any other fluid regarding heat. most of the time you will be under low load, or not moving, in which case the transmission will be cooling down. the problem with using a gear oil is that it's viscosity is too high in cold weather.

your thoughts that atf will not protect the internals of the t56 are out of context. you state that "(a) you don't think atf has nearly the shock protection or boundary layer lubrication like a gear oil does, and (b) that a hypoid gear oil with EP additives would be better."

(a) partially correct however if things are designed and operated correctly you should never be in a boundary layer state of lubrication. suggest you look up the "regimes of lubrication".

(b) the t56 has no requirement or need for such a lubricant. There is no type of gear or gear tooth interface requiring the need of that type of lube. there are millions of transmissions on the road with the same type of gear train including heavy duty on and off road trucks that see more loading than your t56 does and they all run ATF. if there was a problem with atf in a transmission application then it would be clearly evident. gear tooth wear only happens under overloaded conditions and/or lack of lubrication resulting in excessive heat. in those cases a different lubricant doesn't necessary fix that. when a gear case is overloaded you don't need a better lubricant, you need larger gears.

1 FMF

iTrader: (1)

the only good alternative to atf is a "manual transmission fluid". only that is going to have the right frictional characteristics to allow the synchros to work and give you good shifting. the viscosity is comparable to atf. you can buy gm synchromesh #12345349 from the dealer, and they have come out with other manual transmission fluids not labeled synchromesh since the move to dex vi atf. pennzoil synchromesh is available at parts stores usually, and valvoline makes some manual transmission fluids but you'll have to either mail order or special order if you wanted that.