Rear end swap to 3:73, early shift problem

[jimilane]

The rear end in my car is a 3:73. I have a AOD with a tranny kit for better shifting. It shifts fine, it just doesn't shift at the right times when I leave it in OD or Drive.

The tranny has shifted early since the mod. "Stack Shifting" I have heard it called.

Is there a way to overcome this without changing the rear gear to something other than the 3:73?

I haven't messed with the TV cable adjustment. Everyone says to leave it alone and dont' try to mod the TV position.

I think I might mark where the TV cable is now, and experiment a little.

I have talked to many tranny shops and there were no quick fixes. A couple say they can get it "right", but they will have to play with it to get it that way.....and at $65/hr. I don't think it's going to come out very cheap.

I hope someone has some answers!!!!!

Thanks,
Jim

 

[SPEEDYLIFSAVR]

The shift points in the tranny have a lot to do with the position of the TV cable . It sounds as though yours is not adjusted right . Or your tranny may be slipping . I'm sure some trial and error on your part wont hurt .

 

[jimilane]

I don't think it's slipping.

I don't want to mess up anything with the TV cable adjustment.

If anyone could give me some direction as to the TV cable adjustment, I would have a place to start.

Thanks,
Jim

 

[SVT32VDOHC]

Trans is not slipping, and the TV cable won't help much. I had a 91 GT with an AOD and it had an identical problem with a 4.10 gear. 1-2 shift at 5,900 if held to the floor, 2-3 was at 4,700 if held to floor, and it won't shift from 3-4 unless you let off the gas. I had 2 of my Mustang shops tell me it is the gearing.

They both said an aftermarket valve body and updated torqu converter would help that out.

 

[jimilane]

Man, there has to be a way to fix this problem.

Anyone else out there with the same problem?

There is always a way to fix something.

I'm going to try adjusting the TV cable today and see if that makes it any better.

Jim

 

[TheBocSez]

Its shifting earlier because of the gear change.

Your AOD changes gears automatically based on line pressure. Line pressure is affected by RPM. The more RPM the higher the line pressure.

Your change to 3.73 is bringing the RPM's up faster than it did with say 2.73's

So, you car is shifting at the same "line pressures" (RPM) as it did when you had the stock gears in the rear. Its just that the RPM is coming at a lower MPH because of the gear ratio.

I have a lentech street terminator VB with 4.10's and if left in D, its shifts into D automatically pretty quick. With this VB, I can manually shift and hold gears though.

Line pressure can affect shift points some but with the AOD being so sensitive to line pressures, I wouldnt mess with it too much.

Your other options other than a gear change is a different shift kit (you didnt say which one you are running) Baumann makes one that has a lot of adjustment in it.

A valvebody like the Lentech that will allow you more control over your shifts. or a Full manual VB which completely does away with the TV cable and all automatic features.

 

[jimilane]

I understand what you are saying.

I wonder how to change the line pressure and make it work right?

Tell me more about the VB by Lentech. Does the shift pattern change to a 1,2,3,4 instead of the stock configuration? Also, what is the difference in shift hardness with just the VB change.

Yes, I have a transpak kit in my AOD. Not the regular "shif kit". It made the shifts quick. But the old 1-2-1 shift to hold second gear is a little dicey at times. It depends on the technique. I had rather have a different VB.

A full manual VB gets rid of the TV cable? Didnt' know that! Ok, that sounds pretty cool. What's the cost on that, and where can I get one the cheapest? I have seen then before, but I don't remember where.

Thanks,
Jim

 

[TheBocSez]

I think Lentech is one better ones. It changes your shift pattern to

1 = 1st gear
D = 2nd gear
OD=3rd gear
and OD is turned on and off with a switch.

Or you can let it shift itself like a full auto. You can get it in different calibrations. Mine spins em from 1-2 and 2-3 is firm.

Here is a link to their site
http://www.lentechautomatics.com/index2.htm

They also sell full manual VB's, if you want that, but no more putting it in D and fogetting about it.

 

[JGT]

I had the rear end switched to a 3.73 aswell. I didn't have a shift kit or aftermarket vb and it shifted at the yellow line(4800? 4900?) through 3rd at WOT. The AODs wont shift to 4th from 3rd if you're flooring it.

 

[SVT32VDOHC]

I had the rear end switched to a 3.73 aswell. I didn't have a shift kit or aftermarket vb and it shifted at the yellow line(4800? 4900?) through 3rd at WOT. The AODs wont shift to 4th from 3rd if you're flooring it.

+1,000 on that!! Same problem with an old 91 GT I had. Killed the performance. Although there is the old AOD Shuffle...(1,2,1) My car hauled when I did that, but I have heard of people blowing there chit up when they do that!! Be careful...