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Engine & Trans Decisions

82355 said:
Why are you replacing the TH700R4???

Martin
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yaa x2 ?

i would rather have a built 700r4 and its gear ratios over the 4L80-e as its a HUGE & HEAVY trans and still runs the same gear ratios at the older th400 . unless doing crazy power and or heavy towing i would get a built 700R4 or if trans control is what you want a built 4L60 or newer version .

I know 1st hand years ago going from a 700 to 4L80 i missed that deeper first .
 
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wildweaselmi said:
update is I found someone who will help me with the move from a 700R4 mated to a NP241c transfer case changed to 4L80e mated to the same transfer case.
I’m choosing to use Motor City Steel here in Michigan to help with replacement.
Because I have the more expensive version of the Holly Fuel Injection I don’t have to purchase another computer to help with that part. The Holly computer can talk directly to the transmission.

NEEDS:
find the correct year 4L80e (still not positive on what year 4L80e I need to find that works with the Holly and will work with this change)

Will need to shorten rear drive shaft and lengthen front and balance them.

re-tune Holly Fuel Injection

currently awaiting price from Motor City Steel.

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Let me get this straight...

1. Motor City Steel did the initial setup of the 383 and never could get it running to your satisfaction.

2. You already have a new 700R4 that you purchased.

3. Now Motor City Steel is going to "help" you swap to a 4L80E and redo your driveshafts?

Sounds like this is going from bad to worse.

Why don't you sign up for one of Holley's tuning classes and learn how to set up your fuel injection yourself. Make it driveable with the 700R4 before you go mixing up the rest of your drivetrain!

Spend a weekend at the Corvette museum in Bowling Green, it will probably set you back $1,000 or $1,500 between the class, plane tickets, rental car, hotel, meals, etc...
 
nitro_rat said:
Let me get this straight...

1. Motor City Steel did the initial setup of the 383 and never could get it running to your satisfaction.

2. You already have a new 700R4 that you purchased.

3. Now Motor City Steel is going to "help" you swap to a 4L80E and redo your driveshafts?

Sounds like this is going from bad to worse.

Why don't you sign up for one of Holley's tuning classes and learn how to set up your fuel injection yourself. Make it driveable with the 700R4 before you go mixing up the rest of your drivetrain!

Spend a weekend at the Corvette museum in Bowling Green, it will probably set you back $1,000 or $1,500 between the class, plane tickets, rental car, hotel, meals, etc...
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Good catch. I didn't remember the first post.

And I believe that you have some great points here.
 
Having had both a 700r4 and 4l80e in the crew cab, I'd rather have the 4l80e. I like having the options available with the electronic trans.
 
mrk5 said:
Having had both a 700r4 and 4l80e in the crew cab, I'd rather have the 4l80e. I like having the options available with the electronic trans.
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While I understand your points, the 1st gear difference is very noticeable to me. Definitely lose some response from a stop. Having one in the truck already would make me figure things out before shooting more money at something else.
 
It could be I didn't notice the difference because I have a big block. Might be more noticeable with a small block. I noticed more difference after dropping 400lbs with the new setup. I'm not going to berate a guy for how he spends his money; I'm certainly not a good role model. :haha:
 
mrk5 said:
It could be I didn't notice the difference because I have a big block. Might be more noticeable with a small block. I noticed more difference after dropping 400lbs with the new setup. I'm not going to berate a guy for how he spends his money; I'm certainly not a good role model. :haha:
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Keep in mind that I have a 700R4 behind a big block, 2 with small blocks, and the 6.0/4L80E truck isn't as peppy off the line.
I can only imagine how the weight loss affected it. Probably like a C10 with no bed!
 
You need to do try a big block with a 4l80e so you have a good comparison. That 6.0/4l80e combo is probably about the same as a gen 1 SBC as far as off the line regular driving. I'm not particularly impressed with the off the line of our 6.0/6L90 combo but it has the torque management crap messing things up. Not sure if the 4L80e setups had the torque management.
 
mrk5 said:
You need to do try a big block with a 4l80e so you have a good comparison. That 6.0/4l80e combo is probably about the same as a gen 1 SBC as far as off the line regular driving. I'm not particularly impressed with the off the line of our 6.0/6L90 combo but it has the torque management crap messing things up. Not sure if the 4L80e setups had the torque management.
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This one isn't stock. Phoenix transmission convertor and we have adjusted some of the stuff in the computer.
I don't complain much about the shop truck with the 6.0/6L90. It will pull a 30K mixer across town, done it twice now. Those have a 4 to 1 first gear
 
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6872xtc said:
This one isn't stock. Phoenix transmission convertor and we have adjusted some of the stuff in the computer.
I don't complain much about the shop truck with the 6.0/6L90. It will pull a 30K mixer across town, done it twice now. Those have a 4 to 1 first gear
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I would love to put a 6L90 in my crew cab, as least as far as the gearing goes.
 
sweetk30 said:
yaa x2 ?

i would rather have a built 700r4 and its gear ratios over the 4L80-e as its a HUGE & HEAVY trans and still runs the same gear ratios at the older th400 . unless doing crazy power and or heavy towing i would get a built 700R4 or if trans control is what you want a built 4L60 or newer version .

I know 1st hand years ago going from a 700 to 4L80 i missed that deeper first .
Click to expand...
Not trying to start a flame war or anything, but I seem to have a transmission that is not quite up to the task, either that or something is not adjusted properly. I have a semi built 400 with somewhere between 415 and 425hp. Well over 500 ft lbs of torque. The Jimmy in its current form is right around GVW or 6400 lbs. I am running 35's and 3.73 gears with a TH350 and a 1200 stall. I thought I had lost 2nd but it seems I don't have 1st. Transmission was supposed to be rated for 550hp so is there something that I can adjust? Putting the transmission as far down as I can just gives me a shift point at 25mph and then the high gear. I do not want to run a computer so what other transmission could I run that will work?
 
Joel Wilson said:
Not trying to start a flame war or anything, but I seem to have a transmission that is not quite up to the task, either that or something is not adjusted properly. I have a semi built 400 with somewhere between 415 and 425hp. Well over 500 ft lbs of torque. The Jimmy in its current form is right around GVW or 6400 lbs. I am running 35's and 3.73 gears with a TH350 and a 1200 stall. I thought I had lost 2nd but it seems I don't have 1st. Transmission was supposed to be rated for 550hp so is there something that I can adjust? Putting the transmission as far down as I can just gives me a shift point at 25mph and then the high gear. I do not want to run a computer so what other transmission could I run that will work?
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Sounds like a mechanical issue that can’t be adjusted. Even if your shifter was out of whack not allowing you to pull all the way to first it should be starting in first if you put it in drive. The detent/kickdown cable won’t keep it from getting first gear either so that adjustment won’t help.

What does the fluid look like? Cooked? Debris?
 
ZooMad75 said:
Sounds like a mechanical issue that can’t be adjusted. Even if your shifter was out of whack not allowing you to pull all the way to first it should be starting in first if you put it in drive. The detent/kickdown cable won’t keep it from getting first gear either so that adjustment won’t help.

What does the fluid look like? Cooked? Debris?
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fluid is fine, haven't checked the filter yet but want to do that before I have my surgery
 
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