I honestly don't think it would hurt a thing to run a mix of Dextron and F-type. However, I've always ran just one or the other.

BTW, you can tune on LS1Edit until your fingers hurt (yes, I've tweaked mine a bit) but you're not going to do much for helping the holding capacity of the friction materials at WOT (part throttle, yes.) This is where a REAL shift kit and/or F-type fluid helps.

 

If a dealer goes to the extreme of sending your tranny fluid off for analysis just to nail your *** on the warranty then he's probably going to get you on something else as well. You better be running the stock airlid at that kind of bunghole dealer! Seriously, how many dealers would do that? I don't know...I just know that my local dealer certainly wouldn't.

 

Lemme just make one more point directed to you guys that are really pushing the boundaries of the 4L60-E as I have in the past (I took one to a 10.03 in the 1/4.) When the power starts getting serious, the number one problem you're going to have with the 4L60-E is keeping the 3-4 clutchpack alive. It's going to take top of the line aftermarket clutches and all of the best tranny goodies you can find. And even with nothing but the best in the tranny, those 3-4 clutches are going to be toast before long if you're really pushing the power. You need EVERY LAST ADVANTAGE you can get in order to get even a livable amount of passes out of the 3-4 clutches. F-type or some other sort of hard grabbing fluid, IMO, is an absolute must for you.

 

Yup.
I've had lots of shifting problems and tried many solutions. LS1Edit alone just didn't work that great as far as helping my shifting problems. The shift kit helped a ton, but the pump ended up going out due to too much line pressure on my stock trans. I really think my stock transmission would have lasted for a while had the line pressures not been set too high in LS1edit and trashed my pump. Like the Colonel says, the best way to make it hold is to put some good aftermarket stuff inside.

 

Another added bonus to using type F fluid is that its very, very cheap.

 

My T400 with a 5000 stall shifts hard even at idle I use B&M trickshift.

 

Talked with Chuck himself many many times as my first FLP tranny had a glitch, he then told me to try F type. Wound up returning that tranny and replacing it with a "new" one. Not sure what the problem was but Chuck took care of it and have had 0 problems since. F type has taken my 4l60e to lots and lots of low 10 second passes, hopefully 9's tommorow 11/14/03. I did djust freshen up the tranny while motor was out.

 

I'm (finally) having my converter installed Monday. The
GM mechanic (this dealership has racing 'Vettes and he
is the 'Vette mechanic) has been putting B&M Trick Shift
in customers' cars. The dealership has agreed that if I
let them do the converter install, they will honor the rest
of my driveline warranty (except the converter itself).
If they are gonna use Trick Shift and honor my warranty
then it's good by me.

I bought 12 bottles of the Trick Shift today and it sez on
the back that it meets Type F requirements.

There was also a new B&M Trick Shift Synthetic I was
going to buy instead, because it sez it's Dexron/Mercon
compatible. But, in the fine print, it also sez "Not
recommended for transmissions manufactured after 2000"
or words to that effect. Just an FYI for all you shoppers.
Probably, if it rates like Dexron, it slips like Dexron....

 

FYI, I'm not disputing what Chuck told you at all. I'm just wondering why they don't tell all their customers to do this. And in turn, whether or not they fill all their trans' with type F when they build them.

I wonder if there are other properties within Dex that are better for other internal components in GM's trans', hence the reason it's the factory fill. While Type F might be better for the clutches, perhaps it's not as good for other reasons and/or components? While Type F might be a good idea for max effort cars that run very quick times/have heavy weights/lots of power/lots of track time, perhaps you're still better off with Dex for stock to mild/moderate type cars? I'm just taking guesses here....

 

I'm concerned that the F fluid is a band aid for something that is not quite right; maybe off just a little in your tranny.

Not to suggest that GM engineers know everything, but they do focus on durability (warranty claims cost $$) and they could choose the friction properties they desire. Maybe it is nothing but a couple a questions to consider are:
1) Are GM clutch surfaces different from those used by Ford?
2) Does the friction modifier used in the F effect the metals used in the tranny (doubt it) or somehow use more power than Dexron (i.e. trade feel for mpg)?
I don't know the answer to those but it would be nice to know why GM chose that fluid. Then the decision to switch fluid types could be better evaluated.

Tranny fluid is like an oil, maybe we can get Patman to start investigating this topic.

 

I think apply pressure costs HP costs CAFE and there's
as little as can be gotten by with. I'd also like to know
the downside to more grab, I know people have been
doing the Type F thing for decades but haven't ever
heard the good reason against.

 

Ragtop, I agree. That was exactly the point I was trying to make.

I second the nomination for Patman to do the investigation

 

"I don't know the answer to those but it would be nice to know why GM chose that fluid."

My guess (and what I've always heard) is that they wanted softer, smoother, more Cadillac style shifts. It also might be that Dextron helps some parts of the tranny live to 250,000 miles and more (lubricates better since it's slipperier?)...which is fine for a low power stock engine that spends little time at WOT. But 250,000 mile longevity doesn't help those who consider yearly clutch changes as simply regular maintenance.

 

This makes sense, however I don't think Type F will really make all that much difference in the life span of 4L60E clutches in a stock up to 400rwhp or less street driven F-body so long as you keep the trans temps down.

Granted, that is just my opinion. I do agree that for a car that is at the power level and/or racing use of "yearly clutch changes as simply regular maintenance", every little bit counts.

 

With, say, 360 RWHP (which can be done internally stock), I still think the clutch life might be improved somewhat with F-type fluid...especially if there is no shift kit being used which would make the shifts plenty firm for that power level. Sure, it wouldn't be as crucial as a car pushing 500 RWHP+ but I still don't think I'd go so far as to say that it won't matter. At the very least, it gives the shifts, what most of us would consider, a better feel.

 

Colonel: You are probably right about the smoother feel issue, but why not achieve that through the line pressure and shift response times. Those tables are complex enough to indicate that somebody at GM spent a lot of time tweaking them. In the end I assume (maybe wrongly ) that they would acheive the same friction level and feel either way.

 

Like Col said some cars and trucks are set up for smooth, unnoticeable shifts.

I'm going to call Mike @ Yank to discuss, because I am putting a converter in my Tahoe on Saturday and I have a few extra bottles of Trickshift lying around.

Is Type F the brand, where do you get it?

 

I use motorcraft type F in my car and got it from the ford dealer. They also have coastal type F at autozone usually.

I would bet that they use the dexron III to soften the shifts. I was thinking about it and I realized something that always happens when a car comes out and it has nice crisp, clean shifts. The first thing that happens is you read about the car in magazines and they all give it a big thumbs down for having a harsh shifting transmission. I hate the feel of sloppy torque management shifts, but that's just me I guess.

 

Info on different types of ATF taken from this site:

http://www.goa-northcoastoil.com/tips/atffluids.html

GM, Ford, Chrysler Automatic Transmission Fluids


Automatic transmission fluids (ATFs) are the most complex lubricants in the petroleum industry. Containing as many as 15 components, ATFs represent a careful balance of properties needed to meet the unique requirements of automatic transmissions. In terms of viscosity, they may be described as SAE 5W-20 grade oils with exceptionally good low temperature properties. They contain some of the same types of additives used in engine oils, together withfurther material to provide special frictional properties and improved oxidation resistance. Because of their excellent low temperature fluidity and antiwear properties, automatic transmission fluids often find use as hydraulic fluids in industrial equipment and air compressors.

These fluids perform five basic functions:
• Transmit hydrodynamic energy in the torque converter.
• Transmit hydrostatic energy in hydraulic logic control circuits and servomechanisms.
• Lubricate shaft bearings, thrust bearings, and gears.
• Transmit sliding friction energy in bands and clutches.
• Act as a heat transfer medium controlling automatic transmission operating temperatures.

What kind of automatic transmission fluid should you use in your transmission?
THE TYPE SPECIFIED IN YOUR OWNER S MANUAL OR PRINTED ON THE TRANSMISSION DIPSTICK!
CAUTION: Using the wrong type of fluid can affect the way the transmission shifts and feels. Using Type F fluid in an application that calls for Dexron III may make the transmission shift too harshly. Using Dexron III in a transmission that requires Type F may allow the transmission to slip under heavy load, which can accelerate clutch wear. ATF+3 (7176) allows more slippage than other friction-modified fluids.

GM
Dexron III is the fourth in the Dexron series of GM transmission fluids. The original Dexron blend was released in 1967. It was succeeded in 1973 by Dexron II, which offered customers double the oxidation stability. Dexron IIE, which improved upon the oil base of Dexron II, was introduced in 1990. GM upgraded IIE to Dexron III"F" in 1994 for new electronic transmissions introduced in 1992-3. In 1996, GM powertrain introduced electronically controlled converter clutches (ECCC). They were used in limited production of 3,000 vehicles per day in 1997 and in all GM automatic transmission platforms in 1998. Unfortunately the aftermarket Dexron-III specification ("F" level) did not incorporate a test to evaluate fluid performance with the ECCC system. The initial test GM vehicle for the ECCC system was 1997 Buick Rivera with a 3800 supercharged engine, and 4T65-E transmission.

GM has now developed and requires an upgrade Dexron-III specification ("G" level) to meet the requirements of the ECCC system. GM has factory-filled all their transmissions with this "G" level fluid since 1997. GM's new "G" level replaces and supercedes all previous Dexron-III levels ("F", "E", Dexron-II, Dexron etc.). Dexron-III "G" is required for all ECCC GM systems. GM move to Dexron IV for the future has been put on hold.

Ford
Ford currently has three fluids in the market. Ford Type "F" M2C33F specification is required for automatic tranmssions prior to 1977 and select models from 1977 through 1980 models.

Ford Mercon required for select models beginning in 1978, and all models after 1981 using Dexron, M2C138CJ, and M2C166H specifications. Ford introduced their version with a new clutch as Continuously Slipping Torque Converter Clutch (CSTCC) in 1996. Fluids for this transmission are marketed under Mercon-V, meeting specification M2C202-B ("B" Fluid). M2C202-B factory-fill ATF started in Europe market in 1996 and North American beginning in 1997 with select models to their full platform by 1999.

FORD ATF FLUIDS ARE NOT INTERCHANGEABLE. Each fluid must be used in their proper application. Use of the incorrect fluid may result in improper shift-feel, chatter, and potentially early clutch failure.

Chrysler
Chrysler introduced an ATF upgrade in July 1997. This specification is MS-7176E = "MOPAR ATF+3" (PN 4467721). Fluids claiming MS-7176D = "MOPAR ATF+2" must be withdrawn from the market by April 1998. MS-7176E will supercede and replace 7176-D, C, B etc. fluids. Chrysler has developed their own version of CSTCC system (currently MS-7176E must be used in this platform).

A new fluid has been introduced for future factory-fill under the temporary standard MS-9602, known as ATF+4 is schedule for limited use in large vehicles in 2000MY. Availability is extremely limited. Presently, it is not known whether MS-9602 will replace MS-7176E, or for use in addition to, or for specific applications only.

There have been reports of severely damaged transmission using the wrong fluid. Some of these problems go away when replaced with the correct fluid. Follow Chrysler's recommendations to the letter. Ignore the alternative fluid. Chrysler recommends that only ATF+3 Type 7176 be used in all Chrysler automatic transmissions with locking torque converters. Substituting any other fluid can lead to problems. Shifting and engagement of the torque converter clutch (TCC) in virtually all Chrysler automatics is controlled by the transmission control module (TCM), an electronic system, based on a variety of inputs including throttle position, engine speed, input and output speed, and others. The result is that the TCM "learns" characteristics of individual transaxles. The lock-up torque converter must be unlocked, partially locked, or fully locked. In partial lock, a regulated amount of slippage is allowed. If the wrong fluid is used, the TCM can't regulated the slippage in partial lock, the result being converter clutch shudder. Therefore, use only 7176 in all (modern) Chrysler automatics.

Les
ps I am just throwing this in here for informational purposes. Put whatever you want to in your own tranny.

 

I think this statement kinda sums it up...

"Using Type F fluid in an application that calls for Dexron III may make the transmission shift too harshly. Using Dexron III in a transmission that requires Type F may allow the transmission to slip under heavy load, which can accelerate clutch wear. ATF+3 (7176) allows more slippage than other friction-modified fluids.

F type shifts "harshly" (which is exactly what most of us want) and Dexron allows more clutch slippage (whichs is exactly what most of us DON'T want.)