The mythical CUCV 4L80E swap

[Swfb]

I have a m1008 with an 4l80e that has been converted by the previous owner.
According to the ez tcu handheld it shift trough all gears and starts in the first gear.

It only feels like it leaves in 2nd and I think the torque converter is not the correct one.
It has 106 gm 81 engraved.
Is this the correct one for a 4l80e or is this the th400 original?

Is there an advise which converter I should use? Stock 6.2, 36inch tires, stock axles, 4.56 gears.

 

[patracy]

So @Spot_ll offered up a 4l80 for my CUCV. I've got a TCI controller here and I see the TPS sensor to order. But I am wondering about the tach signal. I currently have a tach in the truck, but it has a sensor that clamps onto the alternator to sense the field change and generate a signal for the tach from that. I don't believe it'd have an option for a tach output. I see there's the rare sending unit for the 6.2/6.5 civy trucks that replace the oil pump drive/vac pump, but those aren't cheap at all. I do have the oil pump drive with the STE/ICE sender in my HMMWV that I could rob and toss the CUCV's in place of it. (I don't need the sender in the HMMWV right now) I think I saw mention of some people using this? (And how would it be wired?) I also have found these adapter on ebay that aren't to expensive. They also use the alternator to sense field changes. And it appears to output a tach signal.

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[True Knight]

So @Spot_ll offered up a 4l80 for my CUCV. I've got a TCI controller here and I see the TPS sensor to order. But I am wondering about the tach signal. I currently have a tach in the truck, but it has a sensor that clamps onto the alternator to sense the field change and generate a signal for the tach from that. I don't believe it'd have an option for a tach output. I see there's the rare sending unit for the 6.2/6.5 civy trucks that replace the oil pump drive/vac pump, but those aren't cheap at all. I do have the oil pump drive with the STE/ICE sender in my HMMWV that I could rob and toss the CUCV's in place of it. (I don't need the sender in the HMMWV right now) I think I saw mention of some people using this? (And how would it be wired?) I also have found these adapter on ebay that aren't to expensive. They also use the alternator to sense field changes. And it appears to output a tach signal.

I ended up using a Dakota Digital tach interface unit (DSL-1 if I remember correctly.) I first tried the 6.5 cam driven sender like you mentioned, but couldn’t get a strong enough signal. I don’t know if it was a bad sender and I don’t remember how much testing I did of it, but I know I only had one to try. The Dakota interface does give you a good output to send to the trans controller, but it’s not absolutely necessary. I’ve had the magnetic pick up I used to read the flywheel teeth fail and the trans still shifted and ran normally.

 

[patracy]

From what I've read, that sender only sends 4 pulses per rotation. The work around would be to set the TCM to a 4 cylinder?

 

[True Knight]

From what I've read, that sender only sends 4 pulses per rotation. The work around would be to set the TCM to a 4 cylinder?

Well that’s probably why it didn’t work. TCI should be able to help with that question, because I have no idea.

 

[patracy]

That was me piecing together info. I know the controller can be specified for number of cylinders.

 

[Keith_J]

4 pulses per revolution is correct for a 4 stroke V8. The TCI controller might not recognize the factory engine speed sensor driven off the camshaft and oil pump..the factory ESS actually drives the oil pump..the book "The 6.2 Diesel Engine" published by The Diesel Page has an electronic schematic to convert the ESS into a gasoline engine level tach signal. The ESS signal is a 0.5 to 5 volt sawtooth waveform and it is 8 peaks per camshaft revolution.

Most tachometer have impedance in the 5 to 10 kOhm range. Transmission controllers have much lower impedance due to spurious signal rejection reasons. Like ignition noise..the throttle position sensor for 1991 to 1994 diesel has an impedance of 2 to 7 kOhm..

 

[patracy]

Oops, yes, cam turns 1/2 speed. I'm guessing the signal from it isn't strong enough for the TCI controller. Guess I could create a amp circuit for it.

 

[Keith_J]

Oops, yes, cam turns 1/2 speed. I'm guessing the signal from it isn't strong enough for the TCI controller. Guess I could create a amp circuit for it.

The book I mentioned has a simple electronic amplifier and conditioner on page 128. It uses voltage comparator to trigger the base of an NPN transistor.

 

[powerwagonwc12]

For my upcoming 4l80 swap, I bought the adapter from Advance Adapter for 205 transfer case. It's a 356 T6 aluminum casting with the larger index ring machined into the front. Its also relieved for the oil pan. Dakota Digital tach module and AC Delco TPS round out the sensor suite. Transmission already has the output speed sensor.
Moving the engine forward to accommodate the increased length.

Do you have part numbers for Dakota Digital tach module and AC Delco for the TPS? have you decided on a controller?

 

[Boat Guy]

Soooooooooo...got my M1009 stuck (rookie mistake in NASTY mud) and blew the T-400 trying to get it out. I've got a good shop and am just running through this thread to see if I want to try a swap or just have them rebuild the T-400. I don't drive the beast on long trips; it's more local dirt road use and I'm planning to put a snowplow on the truck once it's running again. Any recommendations to swap/not swap given the use of this vehicle would be appreciated.

 

[True Knight]

Soooooooooo...got my M1009 stuck (rookie mistake in NASTY mud) and blew the T-400 trying to get it out. I've got a good shop and am just running through this thread to see if I want to try a swap or just have them rebuild the T-400. I don't drive the beast on long trips; it's more local dirt road use and I'm planning to put a snowplow on the truck once it's running again. Any recommendations to swap/not swap given the use of this vehicle would be appreciated.

Sounds like you’ll be better off rebuilding the 400. The M1009 already has more highway friendly rear gearing and without a lot of highway driving the 4L80 probably will be worse for you.

 

[Boat Guy]

Sounds like you’ll be better off rebuilding the 400. The M1009 already has more highway friendly rear gearing and without a lot of highway driving the 4L80 probably will be worse for you.

Thanks! Appreciate the recommendation. Rebuilding the T-400 is certainly simpler. Shop says "worst case $2800" but that's over the phone without seeing it.

 

[Finnegan1008]

I’m

Thanks! Appreciate the recommendation. Rebuilding the T-400 is certainly simpler. Shop says "worst case $2800" but that's over the phone without seeing it.

I would get a break down of the parts and labor that go into that price. Are they going to remove and install the transmission for you? Or are you bringing it to them?

 

[Boat Guy]

That's R&R; I'm bringing the truck in on a trailer.