Modded Mustang Forums banner

1 - 20 of 20 Posts

·
K1w1
Joined
·
941 Posts
Discussion Starter #1
What's the actual story regarding going WOT in OD with the 4R70W, or in my case the 4R75W ('04 GT)?
Is it really only to be used for highway cruising? I can understand that going WOT while doing 40 or 50 could create a problem. That would be when the most stress would be placed on the OD belt but if I was doing say 90-100 in 3rd, then selected the OD and then slowly increased speed will that still damage the belt? If I am truly limited to just cruising with the OD then I am limited to 109mph (Paladinmicro speed calculator) compared to 156mph if I use the OD (I have 4.10 gears).

I guess my thinking is that going WOT, or close to it, in OD will only be a problem if I'm going to do it from a relatively slow speed.

Am I correct in my line of thinking or talking through a hole in my...???
 

·
Head Unicorn
Joined
·
5,085 Posts
Yours should be a 70...... 75s came in Machs.... basically the same with slightly different guts though. OD in any WOT is not a great thing. Can you do it? Yes. Should you? Not so much.
 

·
I smell like beef
Joined
·
5,580 Posts
I've read that in late '03 ford started using the 4r75w. They are not very dissimilar.
Check it out here: Ford AOD transmission - Wikipedia, the free encyclopedia

I leave mine in OD on all the time when just driving. If I plan on having fun the OD and TC are always turned off.
 

·
Pays in respect
Joined
·
2,891 Posts
if you go WOT in O/D the transmission downshifts anyway. It's just a precaution that you don't have o/d on while going WOT.
 

·
Super Moderator
Joined
·
13,578 Posts
After years im undecided on this subject. If you go WOT in overdrive then the transmission downshifts out of OD so whats the issue? your never going to be in OD in WOT and I cant see it damaging the OD band if your not actually in that gear. When i first got my car in 2004 before I knew it had and OD button I went though 40+ bottles of Nitrous and never turned OD off, and no damage occured to my transmission. Although ever since I read to turn it off I do so as a precaution.
 

·
Registered
Joined
·
3,368 Posts
After years im undecided on this subject. If you go WOT in overdrive then the transmission downshifts out of OD so whats the issue? your never going to be in OD in WOT and I cant see it damaging the OD band if your not actually in that gear. When i first got my car in 2004 before I knew it had and OD button I went though 40+ bottles of Nitrous and never turned OD off, and no damage occured to my transmission. Although ever since I read to turn it off I do so as a precaution.
The issue is not nailing it while in od, as like you said, it will downshift... the issue is running it at wot and allowing it to shift into od when it runs out of all other gears. the od band is not meant to hold high amounts of hp/tq. That is when it fails.
 

·
I smell like beef
Joined
·
5,580 Posts
The issue is not nailing it while in od, as like you said, it will downshift... the issue is running it at wot and allowing it to shift into od when it runs out of all other gears. the od band is not meant to hold high amounts of hp/tq. That is when it fails.
So when running the 1/4, OD should be off.
 

·
Anandavenkatakrishnan
Joined
·
21,386 Posts
^ if you're stock /bolt on, they wont even have to worry about it. Even most f/i cars as i dont see them going over ~120mph at the end of the quarter, depending on tire size and gearing.
 

·
Super Moderator
Joined
·
13,578 Posts
So when running the 1/4, OD should be off.
While running the 1/4 I would always have OD off just in case you were to accidently shift into OD at the end of your run. On the street I dont see any point in turning OD off, Although I do It as a precautionary cause my car is FI and it will hit 100+ in a hurry.
 

·
Head Unicorn
Joined
·
5,085 Posts
I've read that in late '03 ford started using the 4r75w. They are not very dissimilar.
Check it out here: Ford AOD transmission - Wikipedia, the free encyclopedia

I leave mine in OD on all the time when just driving. If I plan on having fun the OD and TC are always turned off.
Very interesting... I'm gonna do some more research on this topic as it'd be nice to know in the future when sourcing parts. I was familiar with the release of the 75 in 2003 and up until now have only known it to be factory installed in the Mach.
 

·
Registered
Joined
·
3,368 Posts
I don't care if your car is stock or built. Turning od off is a lot easier and cheaper than pulling the trans and having it rebuilt. I wouldn't allow my car to shift into od at wot under any circumstances. Even if you have a built trans, it will still kill it.
 

·
Registered
Joined
·
1,565 Posts
The issue is not nailing it while in od, as like you said, it will downshift... the issue is running it at wot and allowing it to shift into od when it runs out of all other gears. the od band is not meant to hold high amounts of hp/tq. That is when it fails.
thats the best answer, how can it possibly hurt it if its going to downshift anyways, it cant..unless your going to run out of gear like he said^...if im just cruising i keep it on, if im gonna screw around i take it off, my car has seen well over 100 with OD off, really no need to keep it on
 

·
K1w1
Joined
·
941 Posts
Discussion Starter #15
This is the sort of thing that worries me and why I asked the question. Almost everyone has a slightly different opinion.
The other day I found myself doing around the 120 mark, obviously I was the OD was on, and it got me thinking about it. I wouldn't have been WOT but I may have got close to it.
 

·
Danger To Manifold
Joined
·
1,488 Posts
The OD band in the 4r70 and simular transmissions is not a very strong part. When in OD ssa and ssb are engaged and apply the od band and the direct clutch, thus locking the planetary gears into a 1:1 ratio. The direct clutch is much stronger at holding the gears than.the Od band is, so when you shift into 4th and the Od band comes on, it snaps. Even the Kevlar bands still break.

Honestly, unless you're racing and running out of gear in 3rd, you don't need to go that fast.

If this is racing related, get a bigger tire or change your gears to suit your trap speed.
 

·
Anandavenkatakrishnan
Joined
·
21,386 Posts
I wonder what people do that trap over 125mph and have a 28 inch tire already :dunno
 

·
Anandavenkatakrishnan
Joined
·
21,386 Posts
There are auto guys running 4.10s and a 28 inch tire with a lot of power. Maybe they swapped to a c4 trans or something
 
1 - 20 of 20 Posts
Top