AOD Remote Only Trans Cooler setups

[ntsqd]

I owned two square body 4x4 Suburbans successively. Both had 3.73's and wore 285/75R16's, The first one had a TH400 (2.48:1)/NP208 (2.62:1) in it and the second one had a 700R4 (3.06:1)/NP241 (2.72:1) in it. Both would go "there", but the second one was far easier to drive there.

If all you're going to do is drive it on the street then you don't want the wide ratio option. If you are going to drive it in the dirt then the wide ratio option is the way to go and the on-pavement shifting soon won't bother you.

FWIW the real test of the trans cooling system may well be in the dirt, in first - low range.

 

[ba123]

Shifting is a function of three throttle body, not the gears.

I have 35” tires and 5.13 gears.

Here is my final drive.

 

[ntsqd]

It is actually both that determine when/where the shifts happen, they're inter-related and interdependent. The VB looks at things like line pressure, shaft RPM, etc. The gearing determines how far you've physically moved in any particular gear. In general (there's always exceptions) deep gearing + low RPM shift point programing will move thru the gears in the trans rapidly. Tall gears and high RPM shift point programming will really stretch out the time/distance between each shift.

 

[Broncobowsher]

I’m trying to get smarter on AODs so maybe appropriate to semihijack this thread.

I’m struggling to understand why wide ratio gear sets are good for EBs. My AOD rig (which I think is not wide ratio) shifts out of first around town way too soon for my preference. When in 4x4 low, the gearing is reduced further, so not clear why a 2.84 first gear is better in this application.

(I have 35s and 4.88s)

Less overdrive is a big one. The drop from .667 to .70 doesn't look like a lot on paper, but to get a good highway ratio with tallish tires is a deep gear. The fact that you run 4.88 gears and I am sure it cruises the highway nice, and you could probably run an even deeper gear and still be a nice highway cruiser.

Flip that around, getting into the crawl side of things. That jump from 2.4 to 2.8 in first really stretches out when you start multiplying all the gearing to get to the final crawl. A deep crawl is really nice in an automatic. Too many people use the excuse that they get extra torque with the multiplication in the torque convertor. Yes, you do, but it tends to be wild and uncontrolled. You load up the convertor, gain the multiplication, start over the obstacle, and that torque flips into an uncontrolled lurch. Real gearing numbers get rid of that lurch and you just drive over stuff.

 

[ntsqd]

I always felt that the OD ratio in the AOD that I had in the '67 Ranchero was too tall. ~25" tall tires, 3.80:1 gears and the RPM delta between Drive and OD was a LOT. I long looked at the 700R4's 0.7:1 OD ratio with envy.

I hadn't realized that the wide ratio gears also dropped the OD ratio down too. I'd want them just for that.

 

[ba123]

Wide ratio is only 1st and 2nd.

Final drive is 0.67

Also, doesn’t that just make it the same as the 4r70w?

 

[toddz69]

Wide ratio is only 1st and 2nd.

Final drive is 0.67

Also, doesn’t that just make it the same as the 4r70w?

The 4R70W OD ratio is 0.70.

Todd Z.

 

[ba123]

The 4R70W OD ratio is 0.70.

Todd Z.

Only talking about 1-2

 

[ntsqd]

Can you put the whole set of gears from a 4R70W into an AOD? I've never had cause to really look into this, but I recall that a lot of 4R70 parts are considered to be upgrade parts for an AOD.

 

[toddz69]

Copy - I misunderstood your question.

Todd Z.

 

[ksagis]

Shifting is a function of three throttle body, not the gears.

I have 35” tires and 5.13 gears.

Here is my final drive.

View attachment 951410

Are you saying the throttle body can be setup to delay the 1-2 shift point? If so, can you share more?

What speed does your setup shift from 1-2 with medium to light pedal in town?

The difference from 4.88 to 5.13 would only shift things 5 percent so that doesnt seem like a silver bullet. And the 2.84 vice 2.40 seems like it would shift 18 percent. Guessing its much more complicated with things like load, etc

 

[ba123]

Are you saying the throttle body can be setup to delay the 1-2 shift point? If so, can you share more?

What speed does your setup shift from 1-2 with medium to light pedal in town?

The difference from 4.88 to 5.13 would only shift things 5 percent so that doesnt seem like a silver bullet. And the 2.84 vice 2.40 seems like it would shift 18 percent. Guessing its much more complicated with things like load, etc

It’s between your governor, your TB, and your TV pressure.

Yes, the VB can be modified with a shift kit. I put a TCI kit in mine and you have a few choices and inset it for street/strip and like it.

You should try raising your TV pressure als and see wha it does for you. No harm in too much pressure. Try 35 psi with the spacer in, the try 37 or 40 if it’s not shifting how you want. It makes a difference and the AOD is only hurt by too little pressure, not by too much.

Other options are a valve body from Silverfox or one of the others. Dan at Silverfox has an adjustment screw in the side for shift points. I had some trans problems and his didn’t work for me but I might go back to that at some point.

I’m out right now. I’ll see if I can find a good place for a video of shifts.

 

[ba123]

Tried to get the dash. Not sure how easy to hear. Will look at my log when home.

Notes:
TPS 70-85% (Started at 70 and then pressed to 85.
Looks like (between video and looking at logs):
1-2 shift was around 30 MPH and 4500 RPM
2-3 Shift was around 60 MPH and 4000 RPM.

If I press lightly on the gas it will shift much sooner. Happy to take a video of that but you prob wouldn't even be able to tell when it shifts. It will shift lightly in that scenario.

 

[ksagis]

Thanks for all the info.

For me, at more depressed pedal, I’m fine with the shifting, its more of light throttle position that I’m talking about. Truck is in storage with move to Austin at the moment which makes it hard to get better data then memory.

And to make sure I’m using words the same, when you say TB and throttle body, I’m thinking of throttle body on engine. Are you meaning valve body in tranny you are talking about shift kit?

 

[ba123]

TB, VB, TV…sorry, yes and corrected to VB for Valve Body.

 

[Broncobowsher]

Can you put the whole set of gears from a 4R70W into an AOD? I've never had cause to really look into this, but I recall that a lot of 4R70 parts are considered to be upgrade parts for an AOD.

Yes. but shift timing turns into a hot mess. Shift points are based on transmission output shaft speeds, not input speeds. The shift will happen at the same vehicle speed, but a higher engine speed. The tuning of the shift points on an AOD generaly just turns into "close enough" and call it quits. That is where the computer controls really work great. You change little bits of the shift schedule without upsetting any other bit of the shift schedule. And you do it with clean hands.

 

[ntsqd]

I was just thinking about the folks who don't want or can't use a computer controlled trans.

 

[ksagis]

ba123, no need to take a video but if not to much work, could you do one or two runs at much lighter throttle positions and tell me what rpm and speed you shift from 1-2 and 2-3?

 

[ba123]

Yup. I’ll see if I can check later today on a normal start.

 

[ba123]

so at a normal start today, very light gas it shifted 1-2 at about 20 and 3500 and then 2-3 at about 33 mph maybe also around 33-3500.

Tough to be exact.