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Transmission Blow'd Up on Track

OP
cidsamuth
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Thread Starter #63
Picked up the new transmission and got it bolted in, post LSD and 4.3 final drive install. Now to put everything back together.

There was extra cost for the 4.3 based on the troubles @Fusion Works described. All in all, adding the 4.3 to the labor/parts cost of the LSD swap probably cost me another $1200ish …. I don’t know I would do it again.
 


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OP
cidsamuth
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Thread Starter #67
Transmission install done. A couple test drives revealed no problems with it, though it’s tighter and slightly notchier than the old one. An adjustment to the Coolerworx helped that a bunch. Will report back after track work next month.

@Fusion Works Did you have your tune adjusted with the final drive change? The only kooky thing …. RPMs hang a bit …. and even jump up …. when you push the clutch pedal to the floor in higher gears. I wonder if the ECU is confused.
 


OP
cidsamuth
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Thread Starter #69

Fusion Works

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#70
Who was your tuner?

I can't say for certain Randy didn't change my tune for the 4.06. I am pretty sure I told him I had that and I have no rev hang issues. I don't really understand how a final drive swap would cause rev hang.
 


OP
cidsamuth
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Thread Starter #71
Who was your tuner?

I can't say for certain Randy didn't change my tune for the 4.06. I am pretty sure I told him I had that and I have no rev hang issues. I don't really understand how a final drive swap would cause rev hang.
JST. I’ve already sent him logs and would expect a response tomorrow.

Pretty sure the 4.3 confuses the ECU because of load tables. Will see.
 


Intuit

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#72
Transmission install done. A couple test drives revealed no problems with it, though it’s tighter and slightly notchier than the old one. An adjustment to the Coolerworx helped that a bunch. Will report back after track work next month.

@Fusion Works Did you have your tune adjusted with the final drive change? The only kooky thing …. RPMs hang a bit …. and even jump up …. when you push the clutch pedal to the floor in higher gears. I wonder if the ECU is confused.
If there are no codes it may be intentional. There is an explicit warning against powering off without first letting the ECU return the engine to idle. I'm stock software/hardware and have only seen this after aborting a hard pull.
1713741201672.png
 


Fusion Works

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#73
That warning has nothing to do with this specific problem. The warning refers to hard cutting the turbo and oil pressure going to the turbo bearings. 125K rpm without oil pressure will not end well for the bearings.
 


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cidsamuth
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Thread Starter #74
Yea, I think there is confusion. The only thing happening here the RPMs are hanging and evening jumping up when I disengage the clutch. Particularly in higher gears.
 


Fusion Works

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#75
The hang is weird, but the idle increasing with the clutch pedal should have nothing to do with the final drive. Be interested to see if the tune changes it.

With your limited driving can you tell the final is a lot shorter?
 


Intuit

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#76
That warning has nothing to do with this specific problem. The warning refers to hard cutting the turbo and oil pressure going to the turbo bearings. 125K rpm without oil pressure will not end well for the bearings.
I disagree. You're interpreting this in absolutes. LOWERING the oil pressure at a time when turbo RPMs are high doesn't help the bearings.

Yea, I think there is confusion. The only thing happening here the RPMs are hanging and evening jumping up when I disengage the clutch. Particularly in higher gears.
There is no confusion. As mentioned, I only see this "rev hang" if I cut throttle on a hard pull.
 


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cidsamuth
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Thread Starter #77
The hang is weird, but the idle increasing with the clutch pedal should have nothing to do with the final drive. Be interested to see if the tune changes it.

With your limited driving can you tell the final is a lot shorter?
Look at the first post of Jabbit’s thread I dropped above. It’s exactly like the YouTube video he linked, and he edits that first post to state that revising the tune to account for the 4.3 was the solution.
 


Fusion Works

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#78
I disagree. You're interpreting this in absolutes. LOWERING the oil pressure at a time when turbo RPMs are high doesn't help the bearings.
.
A turbo doesn't need that much oil pressure, the galleys are tiny. Ford and common sense just doesn't want you shut the car down after running the turbo hard and potentially hurting the turbo bearings and not flooding oil through the housing to remove the heat. Rev hang was not done because Ford wanted oil pressure for the turbo.
 


Intuit

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#79
A turbo doesn't need that much oil pressure, the galleys are tiny. Ford and common sense just doesn't want you shut the car down after running the turbo hard and potentially hurting the turbo bearings and not flooding oil through the housing to remove the heat. Rev hang was not done because Ford wanted oil pressure for the turbo.
Oil is also used for cooling and flow rate is an important component to that cooling.
 


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