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Topic: Question on going from 2.73 to 3.55 (Read 5751 times) previous topic - next topic

Question on going from 2.73 to 3.55

Reply #30 –
Just spoke with our Auto tranny guy. Here is what he said True fourth is locked up except the electronic units. But other than the electronic units third gear is as follows according to jim

Third gear is 70% locked, fourth is 100%.

Thanks FOE i did not know this. That is crazy how third is a slipper and was told by jim never keep it in DRIVE fore extended periods of time. The 30% slip creates to much heat according to JIM my tranny guy. Live and learn. Slush boxes are not my thing. Just me Thanks i learned something today about the AOD. It has 30% slippage in drive.

He also told me he has converters without lock up. Strange as he tells me in third the tranny is in fact slipping to an extent and looses 30%  He also told me the tranny is not that strong unless it is built to the hilt. Single piece input shaft and no lock up is mandatory according to HIM.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Question on going from 2.73 to 3.55

Reply #31 –
The direct clutch in the AOD and AODe is junk. One of the reasons I put a complete 4R70w stack in mine. I ended up with a total of 6 additional clutches and steels AND lighter and stronger internals, which I'm thinking is good for somewhat lower drivetrain losses. My original direct clutch and it's cast iron drum were reddish black from all the heat when I pulled it out. Kind of like a brake rotor that's been really really hot.

Question on going from 2.73 to 3.55

Reply #32 –
Good info foe!!!
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Question on going from 2.73 to 3.55

Reply #33 –
I didn't even know AODs had a converter clutch. I thought that started with the AODE. GTK. 2.73 is just too high. Even if you drive on the highway a lot, the in town mileage just sucks so bad you would not gain anything with 2.73. One needs to have at least 3.25, but 3.55 is even better. From what I hear, 3.73 not too bad either.

Question on going from 2.73 to 3.55

Reply #34 –
Quote from: Chrome;400241
I didn't even know AODs had a converter clutch. I thought that started with the AODE. GTK. 2.73 is just too high. Even if you drive on the highway a lot, the in town mileage just sucks so bad you would not gain anything with 2.73. One needs to have at least 3.25, but 3.55 is even better. From what I hear, 3.73 not too bad either.

They don't, at least not in the converter, the inner shaft(3rd & O/D) is splined directly into the front hub of the converter... The non-lockup converters for dual input shaft(aftermarket) have the inner shaft splined into the turbine... Those cannot be locked, period...


If you have a engine with a slightly rumpy cam, no less than 3.73 is mandatory, at least that's my opinion and is what I have in my Bird(stock gears for '87 & '88 TC automatic)... If I ever change gears it would be at least 4:10 & maybe 4.30...

As far as need this, have to have that, I have nine years, approx 35K mi(additional, already had 45K when I bought it), 700 drag strip passes(some with a 150 shot) on a STOCK AOD with only a Trans-Go kit and hardened input shaft as modifications(I did bust the orig shaft)... Internally, they aren't as fragile as some lead us to believe...

BTW this trans is from a '89 Super Coupe and is supposed to be one of the best versions, but that's only because it has the larger "A" O/D servo and 7 tooth output shaft... Some of the F & E Series versions used a wider O/D band but I ain't racing in O/D...

BTW #2 I've only used Type F fluid in it since it was installed...

Question on going from 2.73 to 3.55

Reply #35 –
Quote from: TurboCoupe50;400243
They don't, at least not in the converter, the inner shaft(3rd & O/D) is splined directly into the front hub of the converter... The non-lockup converters for dual input shaft(aftermarket) have the inner shaft splined into the turbine... Those cannot be locked, period...


If you have a engine with a slightly rumpy cam, no less than 3.73 is mandatory, at least that's my opinion and is what I have in my Bird(stock gears for '87 & '88 TC automatic)... If I ever change gears it would be at least 4:10 & maybe 4.30...

..

Thanks for the clarafication. I understand now.

 If you have much of a rumpy cam, gas mileage is not much concern. In that case 3.73 would be mandatory. It all depends on how you drive the car. Track time or highway time. I wouldn't put 4.10 if it is mainly driven on the highway. For this guy's engine, I would put 3.73. That would be just awsome.