Auto tranny Torque converter never disengages. Idle set too high??

tom82cj8

Scrambler Pro
City
Austin
State
TX
#1
Anyone know what the factory idle setting was for a Grand Wagoneer with 360/TF727. I recently realized that the torque converter never disengages on my Scrambler's TF727. The Howell TBI setup idles around 700 rpm. Is this too high? Any suggestions on getting the torque converter to let loose?

Thanks,
Tom
 

John N

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#2
I've got a 360/automatic with the Howell, too. Mine was idling too low after I installed the Howell. There is an idle screw that can be adjusted in the base of the TBI. You may need to go the other way on that screw. On mine, the screw was covered with a metal cap, that I had to drill through to make adjustments. I think I'm set at about 700 rpm.
 

Randyzzz

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Redmond
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#3
Tom- by never disengages, do you mean it still pulls hard at idle? 700 should be fine, but there will always be some pull due to the nature of the beast. It should accelerate slowly when releasing the brake- (no gas applied) and eventually get up to 10-15 mph or so on level ground. If it pulls hard at idle, there might be something wrong with your converter.
 

tom82cj8

Scrambler Pro
City
Austin
State
TX
#4
It doesn't pull that hard at idle in 2HI. In 4Low running down steep terrain I have to shift into neutral to stop sometimes. I am going to burn another chip with an idle setting of 500rpm and see how that compares. All of this came about after I complained about the performance of my Navajo brake setup. Harold suggested that my trans may not be letting up.

Thanks,
 

kohldad

SOA Member
City
Goose Creek
State
SC
#5
700 should be fine, but there will always be some pull due to the nature of the beast. It should accelerate slowly when releasing the brake- (no gas applied) and eventually get up to 10-15 mph or so on level ground.
That sounds about right. In hi range, a light foot on the brake pedal is all you need. In low range, there is almost 3 times the force being applied and therefor takes 3 times the brakes to hold it there. This should require about the same or slightly more than the brake pedal force required to come to a moderate stop, defintely not just a rest the foot on the pedal force.

On a muddy flat trail in 2lo, sometimes mine will just slide the front wheels along unless I'm in 4lo so the front disc helps hold the back wheels from turning via the drivetrain.

To help determine if it is the torque converter or brakes, I would have to ask the question of how are the brakes when trying to go from 60 to 0 in a decent stop?
 

John N

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#6
I had to upgrade my brakes to conquer this. I got the Navaho set-up from Off Again. Vanco's is similar.
 

tom82cj8

Scrambler Pro
City
Austin
State
TX
#7
Hey John N-

I have the Navajo setup. I bought it after trying many different master cylinder/booster combos. Harold at Off-Again was the one who suggested I look at idle speed and my tranny. I haven't ever felt like the Navajo setup lived up to everything I had heard. I had a CJ7 that was setup exactly the same as my Scrambler except I used a G. Wagoneer master cylinder on a GM dual diaphragm booster and it was amazing. The only other difference. That CJ7 was a manual trans..... It stops well, but not as good as a modern 4-disc system. I don't even mind shifting into neutral. There are just a few times when you want maximum brake power and then max acceleration. This isn't possible with the "neutral" solution.

Thanks,
 

John N

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#8
Since I'm running Dana 44's, I have larger brakes at all 4 wheels. The larger Scout II drums in the rear (11" x 2.25/2.5") and FSJ Waggy discs up front. Mine stops very well, my son says it stops like a Honda Civic. For your brakes, how long since you've been through them? I thought mine should be great, at the wheels and had to pull a rear axle. The rear shoes were about gone...only 12-15k miles, I figure, if that. Off roading takes it's toll on this stuff. Was your torque converter anything special, other than stock? I know you can idle it way down, too, so 500 shouldn't be a problem. It may be as simple as a bad converter, that's just not releasing when it should.
 

tom82cj8

Scrambler Pro
City
Austin
State
TX
#9
Brakes should be good, but I will check them. I have the FSJ Waggy disc/drum combo. I can burn my own chips so making a 500 rpm idle chip is just a matter of getting out the equipment. If it will run well at 500, that is better any way. Do you know if the TBI setup has an AC compressor input that will send it to a high idle under load? I thought I remembered a wire that does this. Can't remember if it was grounded or 12V+. There is a big difference...

Tom
 

John N

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#10
tom82cj8 said:
Do you know if the TBI setup has an AC compressor input that will send it to a high idle under load? I thought I remembered a wire that does this. Can't remember if it was grounded or 12V+. There is a big difference...

Tom
That I don't know, but you might find the answer in the Howell instructions or from their tech dept.
 
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