What transmission fluid should I use for a 904 with a shift kit!?

[S'cuder]

Ran ATF +4 for over 20 years. Cheap in bulk at work. Presently running blue fluid

Is that the HPL stuff? What do you think of it?

 

[QuickDart360]

Ran ATF +4 for over 20 years. Cheap in bulk at work. Presently running blue fluid

Blue fluid?

 

[Woody500]

There are more than a few threads on this topic... often contentious as these tend to go.

Type F is often mentioned for more firm shifts.

Plus 4 only.
The reasons are spelled out in other threads , so I won't go there. And besides I don't remember all the particulars.
That's what A-Bodies is for, additional memory storage!

 

[Woody500]

Royal purple works great!

Sorry , haven't used any RP products since the Scandia/Dick Simon takeover debacle(pushing Dick Simon out). That Scandia owner was connected to RP somehow, maybe just sponsor deal, not sure IIRC.
Later fired as Bill Gates Financial advisor when his 80s SEC investigation & bank fraud conviction, became publicly known to Mr Gates.

 

[Woody500]

Anything red will work
Dex/merc is fine
Type f is fine.
+4 is fine
Dex VI is fine

Dex/merc will lubricate bushings and planetaries better than type F but type F will have firmer shifts due to the lack of friction modifiers in the additive package. Less friction modifiers, the quicker the clutch packs engage when they are applied. Other fluids have friction modifiers which help with smoother shifts. However, with a shift kit valve body, no matter what the fluid, it will shift firmer than stock application.

I run Dex/merc in my race car 727
5.40s at 125mph in the 1/8
Nick Allison runs Dex/merc in his 904 running 10.80s at 126 in 1/4
Other team cars with big power run type f. I do all the transmissions in our team cars and none of them have issues with any fluid. Being a builder, I tried different fluids to see if there was any difference in performance on the track, and during overhaul. So far I’ve found nothing.

I used to run type f as long as I’ve raced. But with valvoline Dex/merc being $20.24 a gallon at Walmart, I switched to it and car shifts the same as it did with type f.

So as stated, anything red will work.

Friction Modifiers like you describe, seem to be to help clutches slip for easier(softer) application, ie less harsh shifts.
Doesn't sound like what most here want out of their trannies.

 

[Woody500]

I don't know...I feel like whatever I say will be met with disdain and ridicule...

but when I ran a automatic Mopar it was Type F...

Long ago, but look up Superceeding Transmission oil types for each & it spells it all out.
Previous to Dexron was Type B, anybody still using that? Also I'd bet New Dexron is now to a new Spec.
Anyone still use Non Detergent motor oil? Why when there is something better.

 

[340six]

So you're saying how smart they were yesterday or how smart they are today? You still use the green coolant too? LOL sorry, I shouldn't have. Just couldn't resist. We know brake linings are made of different materials today. We can image transmission parts may be different too today too.

I use Red Catapillar Auntifreeze. It is extended life and for aluminum parts. I have an entire top end made of old beer and soda cans.
My father in law worked at a Cat Dealership most of his life. He swears by it.

 

[Dave999]

Anyone still use Non Detergent motor oil? Why when there is something better.

Yes i use non and low detergent SAE30 in my Aussie borg warner manual 4 speed.... i actively want the sludge to stay at the bottom and not be running through the bearings....
if i can find anti foaming SAE30 for transmissions i'll use that. but motor oil is just fine

thin enough for rollers and needles but not think enough to make the synchros be in effective

 

[Icetech]

Have only ever ran Type-F.. have never had an issue.

 

[Woody500]

Yes i use non and low detergent SAE30 in my Aussie borg warner manual 4 speed.... i actively want the sludge to stay at the bottom and not be running through the bearings....
if i can find anti foaming SAE30 for transmissions i'll use that. but motor oil is just fine

thin enough for rollers and needles but not think enough to make the synchros be in effective

Thats acceptable. But that's not in an engine. I don't even use it in my lawn mower engine anymore.
Worked at a military museum in the 80's & they still used it because the old
Federal Technical Manuals from WWII were their only source of info.
Showed them superceeded specifications, & it still took a while to convince them to use multi-grade or detergent oils.

 

[A body]

Blue fluid?

LAT Pro atf. 20 weight.

 

[cosgig]

whatever the dextron III compatable fliuid is onthe shelf these days... no need for type F. its not 1970 anymore..

i've been using this for years. no issues. STP Dexron/Mercon Automatic Transmission Fluid 1 Quart


It might not be 1970 anymore, but the 904 is still from 1970……

.

 

[abodyjoe]

It might not be 1970 anymore, but the 904 is still from 1970……

its running modern (not 1970) materials in it.

 

[Woody500]

But the rebuild parts are not , unless you find NOS parts. But why, when something better is available.
I'd think frictions you can buy are improved, bushings too. Sealing rings probably a material that wears better, just like piston rings.
Improvements are made with many parts. Shouldn't you use newer spec oils to take advantage of it all?
Research.

 

[71Demon540]

Friction Modifiers like you describe, seem to be to help clutches slip for easier(softer) application, ie less harsh shifts.
Doesn't sound like what most here want out of their trannies.

Agreed, but in my experience it has shown no softer application of shifts when going to a shift kit or reverse manual valve body. But again, any of them will work. Type f is plenty fine. And will shift the hardest.

 

[Woody500]

Agreed, but in my experience it has shown no softer application of shifts when going to a shift kit or reverse manual valve body. But again, any of them will work. Type f is plenty fine. And will shift the hardest.

Does B&M still sell their oil that has friction modifiers in it, that includes steel? Apparently super fine particles. How does that ever stay in suspension?
And how long between rebuilds if using it.

 

[abodyjoe]

But the rebuild parts are not , unless you find NOS parts. But why, when something better is available.
I'd think frictions you can buy are improved, bushings too. Sealing rings probably a material that wears better, just like piston rings.
Improvements are made with many parts. Shouldn't you use newer spec oils to take advantage of it all?
Research.

whats what i was saying..

 

[abodyjoe]

i'm not into hard shifts. i'm in to quality shifts.

 

[Woody500]

i'm not into hard shifts. i'm in to quality shifts.

Hard shifts are quality shifts. Mostly because to soften shifts you must have a slight overlap , ie the trans shift timing delays lower gear disengagement & allows next gear to partially engage when shifting to make shifts softer.
Vice versa for downshifts of course.
Shift kits change the timing and shifts are firmer. & probably trans runs a bit cooler. Both help performance.

 

[abodyjoe]

Hard shifts are quality shifts.

ummmm, no.

 

[Woody500]

ummmm, no.

Just ignoring the rest of it. ummmm, OK.

 

[abodyjoe]

a quality shif does not have to be hard.. the rest did not need to be addressed.