Fox T-Bird/Cougar Forums

Technical => Drivetrain Tech => Topic started by: jcassity on October 04, 2016, 01:33:48 PM

Title: transmission fluid change **SOLVED**
Post by: jcassity on October 04, 2016, 01:33:48 PM
once upon a time i got a 20th coug

my last trans filter/fluid change i let what appeared to be about 5 qts or so come out.
i put the same amount the back in.
i test drive and for some mystical reason the car slips sometimes in curves so i add more.  I keep on adding and adding until the result seems i have about 3 times the fluid level i need.  AT this point the slipping is brought to a minimum... although i am wayyyyyyyy over full.

Its been like this for several thousand miles and i just ignore it.

fast forward to about three years ago, i did a filter / fluid change on my son's bird, no issues there at all.  We did however with the pan off start up the car and shift from r to d to help dump out the converter.  No issues.

fast forward to a couple weeks ago, my son did his fluid / filter and simply drained the what was in the pan and did a filter.

he now is in the same problem area i am at, he had to add a qty of trans fluid that the dipstick says he's nearly at tripple the amount required.  He also had to add more fluid because of minor slipping while in curves or pressing the pedal to hit passing gear slippage.

i called around asking if others have had this symptom of what appears "air" is getting sucked in somewhere.

I can only suspect perhaps that little tiny square filter gasket is getting "cut" when the filter is tightened or,, a valve body gasket is cracked and by draining fluids, this dislodges any particles that was keeping things sealed up.

anyone else have this happen,, car slips after a simple fluid / filter change?

perhaps a filter design flaw? a gasket flaw?  Or even perhaps a viscosity change in the fluids made recently?

all i know is that if you simply just add a lot of fluid till the slipping stops all is well.

i am half temped to experiment with zero weight engine oil ratio to trans fluid and see if that allow me to get the fluid level down to the normal level.

thoughts?
Title: transmission fluid change **SOLVED**
Post by: mcb82gt on October 04, 2016, 09:50:50 PM
That is odd.  Ive done mine with no problems. 

What fluid did you use?
Title: transmission fluid change **SOLVED**
Post by: V8Demon on October 05, 2016, 08:00:50 AM
Are you checking the fluid level with the vehicle on, warm, and in gear as you are supposed to? 

Full in the condition I described above will show vastly overfull when the car is sitting in park and off.
Title: transmission fluid change **SOLVED**
Post by: jcassity on October 05, 2016, 09:37:30 AM
i use type f when i can find it or dextron2 or 3

i know that during long road trips i am still really over full at idle in park,, i'll try putting in drive
Title: transmission fluid change **SOLVED**
Post by: TurboCoupe50 on October 05, 2016, 01:36:50 PM
Often when adding a quantity of fluid, enough will hang inside the tube so it appears to be overfull when actually still low... Of course this remedies itself in a couple of hours, or at least over night...

Probably 10 years ago I quit pulling transmission pans when changing fluid... I connect a hose to the upper trans cooler line, start engine and let it pump into a 5 gal bucket... While still running/pumping, I'll add approx three quarts LESS than a full fill(or approx 8 qt for AOD) and let it pump till flow starts to diminish... Fluid will change color when new starts coming through... At that point I reconnect line, top off(this is where you'll need those three quarts), done...

No under car necessary...
Title: transmission fluid change **SOLVED**
Post by: ZondaC12 on October 06, 2016, 01:07:55 PM
The last filter I bought had a small instruction sheet that cautioned against over-tightening one of the filter bolts as it's near the 3-4 shift valve I think. Said it could deform the bore and make it stick.
I've definitely always needed to move between all selections N/D/R to get fluid everywhere and do it a few times, sitting there for a minute or two in each before I'd get engagement.
Title: transmission fluid change **SOLVED**
Post by: mcb82gt on October 06, 2016, 07:07:09 PM
Quote from: ZondaC12;457355

I've definitely always needed to move between all selections N/D/R to get fluid everywhere and do it a few times, sitting there for a minute or two in each before I'd get engagement.

For sure, I just took that as common knowledge.  The trans must be hot and up to operating temp, before checking.  Then cycle each gear and back up through, then check.
Title: transmission fluid change **SOLVED**
Post by: jcassity on October 08, 2016, 11:59:06 AM
in drive and engine up to operating temp,,,

fluid reads up to the "F" in the word "IF"

,,,which is way too full in my opinion
Title: transmission fluid change **SOLVED**
Post by: jcassity on November 05, 2016, 10:16:42 PM
problem solved,
son got down and dirty again and decided to investigate.

Starting from scratch with new fluid and filter he finshed up and found his problem.

He says he must have forgot to put the tiny square gasket on because it was not there.

makes me wonder if mine is cracked,, i never forget that gasket,, but since they are so thin,, mind might be split due to over doing the tightness of the filter bolts.
Title: transmission fluid change **SOLVED**
Post by: ZondaC12 on November 17, 2016, 03:58:17 PM
Hmm, maybe that allows cavitation in the fluid inlet.
Title: transmission fluid change **SOLVED**
Post by: mcb82gt on November 19, 2016, 09:57:09 PM
Quote from: jcassity;457687
problem solved,
son got down and dirty again and decided to investigate.

Starting from scratch with new fluid and filter he finshed up and found his problem.

He says he must have forgot to put the tiny square gasket on because it was not there.

makes me wonder if mine is cracked,, i never forget that gasket,, but since they are so thin,, mind might be split due to over doing the tightness of the filter bolts.

How would that change the level in the pan for misrepresentation on the dipstick?
Title: transmission fluid change **SOLVED**
Post by: jcassity on November 19, 2016, 11:20:35 PM
what we think is that where the filter attaches the fluid is normaly a tad lower than that and was sucking air

lets say we include 3/4'' fluid level change for when the car is in curves and such,, g forces slinging fluid

so lets say the pan is 14'' x 14'' ,, just estimating and the variance is a 3/4'' delta

14x14x.75=  approx 147cu inches


there are 1728 cu in in a cubic foot

it takes approx 7.4gal of liquid to fill 1 cu ft or about 30 qts

each qt would take up about  58 cu in of space,,

he needed about 3 or so more than normal to make stuff work and it was still sketchy.
Title: transmission fluid change **SOLVED**
Post by: jcassity on November 19, 2016, 11:25:53 PM
so to over come all this,, we had the pan completely full,, and even the dip stick tube was probably getting filled up as well.