best transmission fluid for '04 cobra?

Sanchez209

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4 quarts and it's ATF.

Yea but ATF is for auto transmissions isn't it? Okay my cobra has 115k got it with 108 but everything works fine I just want to do the transmission oil change....which one do you recommend? And I do race the shit out of it if that helps
 

bubblehead93

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many companies have synchromax equivalents, before coming to Guam used AMSOIL's version, hard to get out here, switched back to Penzoil... I like the AMSOIL better, maybe psychosomatic though, car shifts good, 12 years, one tranny rebuild, when I was inside the only wear was on the blocker rings, bearings were all good, no sign of excessive heat... I autocross and drag race...
 

JuStAkId

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Pennzoil synchromesh. I noticed a smoother shift when the trans would heat up compared to mobil 1 atf
 

Sanchez209

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Oil change

Got my oil tranny changed today I put penzoil synchromesh....it merks way better shifting at high rpms...only bad thing is when I drained it it only had like 1/4 of a quart....hopefully I didn't hurt my tranny
 

Sanchez209

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I took it to pep boys I think they used the bottom one that's all they told me that I had no oil in it
 

Rambro

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The guy who rebuilt my trans strongly advised against synthetic ATF.. After I bought four quarts of Amsoil ATF :fm:
 

03SVT_SWE

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Just swithed to Mercon 5 from Motorcraft, I can not recommend it!
It immediately started to rattle, even at idle. As soon as I depress the clutch the sound is gone.... Anyone else having the same issue?

I guess I will switch to RedLine D4 as soon as the snow is gone!
 

Sanchez209

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Okay I'm back at pep boys that penzoil synchromesh sucked after all...I noticed that at high rpms above 4k it will get super hard to shift I even grinded my gears cuz it was stf hard! Pep boys recommended me the motor craft dextron 5 see how it goes
 

venom1307

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I know I'm dragging out a older thread, but I'd like to express my background. I've been rebuilding transmissions for -/+ 10 years now (less and less the older I get, lol). I've had a great working relationship with some of the biggest names in the business (where most of you send yours out to). Anyhow, I've done more GM and Ford T56's then I could even begin to count and this is my thought on fluids, and my personal expirences with different fluids ............

* cheaper, non synthetic, parts store brand (I know it's made by a reputable source, but to what specification ?): works well when warm, can make internal noise a little more audible then other fluids. Won't hurt a thing, and technically what Ford/Tremec recommend.

* Royal Purple: I have personally witnessed it make a non grinding trans grind. It's good stuff for the bearings, TOO slippery for the synchronizers to do their job. The factory Timkin bearings are extremely tough and will take quite a beating for 100k+ miles. It's the synchronizers and their ability to effectively "stop" the next gear, that's the key factor in this "fluid" topic.

* Mobil1: I'm a big fan of particular M1 products, have been for many years (I'm not going to get into API ratings and such .... They're the same as oils 2x their price). Always had great luck. When I do a fresh rebuild with known good synchronizers and bearings, it's the fluid of my choice and have gotten excellent feedback with customers.

* Synchromesh: excellent stuff ! About the same viscosity as ATF (approx a 30w). It's actually a pretty well engineered product. It slightly "swells" the blocker rings, thus giving you a better shift (and that equates to less internal wear). Very good choice for a trans with miles on it, or some customers have asked if it was ok with their new trans ..... Absoutely, but still prefer M1 on a fresh rebuild.

GM has been running synchromesh in their T56's since the introduction. I can personally tell you that there's no specific differences to speak of between the Ford VS GM trans, nothing that pertains to "this" topic anyway. I highly recommend GM synchromesh ! It's what I run in my personal cars. I realize that Pennzoil makes Synchromesh and is 1/2 the price .... Seems to me there IS a difference though: the color, the smell, just seems like a slightly different fluid (for the better, but I cannot confirm differences in the 2). That said I run to local GM dealer .... Again, to each their own on that one. Nothing wrong with Pennzoil's stuff though, I'd recommend it any day over a uber slippery synthetic fluid.

There's a fine line here fellas ..... You want some slick synthetics for the bearing life, but you NEED more friction to make the blocker rings do their job. The blocker rings is what gives the transmission it's "characteristics". That said, to me, those super high dollar synthetics is like this: great for bearings, horrible on blocker rings.

Food for thought. My car is going on dyno tomorrow after a long hibernation .... Plan on doing a full fluid swap on it today including Pennzoil Sychromesh in the trans.
I know this is an old thread. Is it the gm synchromesh in the black bottle 88900333 ?

1ask because I see there is a white bottle that also says synchromesh that is friction modified and semi synthetic 88900399…

LMK thanks.
 

olympic

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I know this is an old thread. Is it the gm synchromesh in the black bottle 88900333 ?

1ask because I see there is a white bottle that also says synchromesh that is friction modified and semi synthetic 88900399…

LMK thanks.

The black bottle is the one you want.
 

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