C-6 to E40D?
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Junior User
Joined: Jan 2003
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From: Vincennes, IN
C-6 to E40D?
My 89 7.3 has a C-6 in it. I understand its a great, bullet proof transmission as far as towing goes. There are two major things I don't like about it. One, it shifts at approx 2600 - 2700 rpm and you almost crack your head on the window when it does. And two, on the highway it runs about 3000 at 60mph. I drove my brothers 94 7.3 with an E40d for the first time yesterday. I couldn't believe what a difference it was. This truck took off like a bat out of heck and just kept going, climbing well past the mph mine would do at max RPM. My questions are:
Would it be worth switching my C-6 for an E40D or would it be better to go manual or some other trans?
What RPM is exceptable for a diesel? All our tractors run around 2300 WIDEOPEN and my truck is running 3000 down the highway?
Thanks for your help!
Would it be worth switching my C-6 for an E40D or would it be better to go manual or some other trans?
What RPM is exceptable for a diesel? All our tractors run around 2300 WIDEOPEN and my truck is running 3000 down the highway?
Thanks for your help!
Senior User
Joined: Feb 2003
Posts: 315
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From: Alabama Gulf Coast
C-6 to E40D?
My E4OD shifts at about 2,000 rpm's on all gears and runs down the road at 1,800 rpm's at 65 mph unloaded.
Can't help in regards to changing out for another manual tranny but can say regarding changing to the E4OD, that it would be difficult. From what I've seen about the C6 in my manual, the tranny shifts in regard to vacuum applied? The E4OD, however, uses a computer module called the TECA relay along with several sensors which tell it when to shift. You would have to buy and install all of the sensors and the TECA, and the wiring harnesses between all of the above........I think. Hope this helps.
R.A.
Can't help in regards to changing out for another manual tranny but can say regarding changing to the E4OD, that it would be difficult. From what I've seen about the C6 in my manual, the tranny shifts in regard to vacuum applied? The E4OD, however, uses a computer module called the TECA relay along with several sensors which tell it when to shift. You would have to buy and install all of the sensors and the TECA, and the wiring harnesses between all of the above........I think. Hope this helps.
R.A.
Posting Guru
Joined: Sep 2002
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From: Northeastern Pa - USA
C-6 to E40D?
Well, now. The c-6 is a great trans. What is the gear ratio in the rear differential?? That is bad boy you are interested in changing. Also, you can add on a auxiliary trans that will change the final ratio in the engine. I have a 88 7.3, c-6 with 410 rear ratio. I installed a gear vendors aux trans that mounted right to the rear of the c-6. It changed the final ratio and saved 22%, which brought the final ratio to approx 320. Changed my top speed to 80 plus.
To install an E40D you will have to reqire the cab to get the ecm in line to control the trans.
You may be able to readjust the vacuum switch on the injector pump to relieve some of the speed that is being built up before shifting or NAPA has an adjustable vacuum modulator switch for the trans and you can change the vacuum there.
The 7.3 will run at higher rpm than a tractor engine. The v-8 seem to run higher speeds than the inline 6 diesel.
Let us know how you go about the change.
To install an E40D you will have to reqire the cab to get the ecm in line to control the trans.
You may be able to readjust the vacuum switch on the injector pump to relieve some of the speed that is being built up before shifting or NAPA has an adjustable vacuum modulator switch for the trans and you can change the vacuum there.
The 7.3 will run at higher rpm than a tractor engine. The v-8 seem to run higher speeds than the inline 6 diesel.
Let us know how you go about the change.
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Junior User
Joined: Jan 2003
Posts: 85
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From: Vincennes, IN
C-6 to E40D?
I'm currently talking to a guy just south of me with a wrecked 89. It has a zf 5 transmission. Hes willing to sell me everything minus the flywheel/clutch assembly and steering column for 800. Is this a good deal? Would this conversion be easier than to an E40D or would it be pretty much an even draw?
Thanks for the help!
Matt
P.S. I have 4.10 gear ratio in both the front and rear.
Thanks for the help!
Matt
P.S. I have 4.10 gear ratio in both the front and rear.
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Joined: Feb 2003
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C-6 to E40D?
Mhalter,
I guess it all depends what you are doing with the truck. I had a 95 6.9 with a C6. At 150,000 miles I had it rebuilt for about $350 with a new converter. I have had friends spend over $1500 to rebuild the E4OD at under 100,000. The ZF 5peed has its issues also, plan on an $1800 rebuild if that goes bad+ $600 for the single mass flywheel clutch kit. Have you thought of going to 3.55 axle ratios? I would run the C6 till it blows and worry about it then.
Just my .02
I guess it all depends what you are doing with the truck. I had a 95 6.9 with a C6. At 150,000 miles I had it rebuilt for about $350 with a new converter. I have had friends spend over $1500 to rebuild the E4OD at under 100,000. The ZF 5peed has its issues also, plan on an $1800 rebuild if that goes bad+ $600 for the single mass flywheel clutch kit. Have you thought of going to 3.55 axle ratios? I would run the C6 till it blows and worry about it then.
Just my .02
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Junior User
Joined: Jan 2003
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From: Vincennes, IN
C-6 to E40D?
How much pulling power will I loose from going to 3.55s from 4.10s? I live on a grain/produce farm. My truck gets used alot for pulling anhydrous wagons, towing farm eqiupment on a gooseneck, etc. And during the summer months it is on the hiway for nearly 200 miles a day delivering produce. Which is why I want to get rid of the high rpm at hiway speeds.
Thanks for your help so far.
Thanks for your help so far.
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Joined: Feb 2003
Posts: 11
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C-6 to E40D?
Are you running stock sized tires? If you are running bigger than a 33" tire, you may lose some power for towing. 3000 RPMs on the highway sounds lkie too much though. I have had 355s on several of my gas powered truck and loved them. I am going to change my 96 PSD 5 Speed from 410s to 355s. I currently have the stock 265/75 tires and run about 2500 RPMs at 70 MPH. Have you gotten your C6 to shift better yet?
My old 85 6.9 C6 was shifting hard when I bought it. There is a vacuum switch on the throttle body that can make it hold shifts if it is not adjusted correctly.
My old 85 6.9 C6 was shifting hard when I bought it. There is a vacuum switch on the throttle body that can make it hold shifts if it is not adjusted correctly.
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Freshman User
Joined: Oct 2002
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From: Boerne USA
C-6 to E40D?
I hade a 89 7.3 and when i bought it it had a 4.10 in it. I changed it to a 3.55 and lost alittle pulling power but top speed was 85 or a little more. 73 was at 2700 RPM's.
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Thread Starter
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Junior User
Joined: Jan 2003
Posts: 85
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From: Vincennes, IN
C-6 to E40D?
1-4-ford,
Where is the vacum switch? Is it the arm looking thing that pivots on the driverside of the injector pump, held by two screws? I tried moving it from one extreme to the other with no differnce in the shifting at all. Could this mean it is malifunction and I need to replace it?
I already replaced the vacum modulator on the transmission to no avail. I tried both that the local Napa store said could be the one I need. One with a black strip, and one with a green. Using the green modulator allowed me to shift and 3000 instead of 2500-2600 like the black one does.
OH, btw, I'm running 33" BFG MTs.
Thanks again!
Where is the vacum switch? Is it the arm looking thing that pivots on the driverside of the injector pump, held by two screws? I tried moving it from one extreme to the other with no differnce in the shifting at all. Could this mean it is malifunction and I need to replace it?
I already replaced the vacum modulator on the transmission to no avail. I tried both that the local Napa store said could be the one I need. One with a black strip, and one with a green. Using the green modulator allowed me to shift and 3000 instead of 2500-2600 like the black one does.
OH, btw, I'm running 33" BFG MTs.
Thanks again!
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