[killakev]

I've been very interested in this subject after getting used to my 68 GTO. It's gears are way to high for MY liking. Can burn rubber for miles off the start but highway driving is almost unbearable. I like to cruise on the highway also and not be limited to "town" driving. Anyone thinking about changing their gears need to read this post:

www.gtoforum.com/f12/gto-gear-ratios-16289/

[rohrt]

I took a drive to the neighboring town. Its posted at 65 so most are driving 75. I'm pushing about 3000 to 3200 and still not keeping up with traffic with my 3:36 gears. Plus the temp was rising a bit. That just kind of sucked. Driving 55 is fine for the most part.

I was playing with an online RPM calculator. I like my cruise rpm around 2500. I found out my tire are only 25.5" tall and the 2.93 would be ideal for me for interstate driving. I have two 8.5 sitting around I know one is 3.08. I will need to check the other.

I just suggest getting some miles in and see what you can tolerate.

[HWYSTR455]

You can have both strip and highway with an overdrive, why compromise? Just accept the fact that to have both, it costs a little more. If you coughed up the change to get a procharger, why give up in the home stretch, just do an overdrive.

Gear has a considerable impact on 1/4 mile times, but honestly, when you think about it, if someone is picking up in the 1/4 by going to a more highway gear, then they are really just crutching a traction or chassis problem. Or cam selection was off to begin with.

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[1969GTO]

To do an over drive, the co$t must be massive.

[rohrt]

Any OD that can take a beating from a 455 will cost more then 3K. The only exception would be if your doing a direct manual replacement from a 4 speed to a 5 speed, then maybe a little cheaper.

Jake shoe th200r4 $2500 + torq converter + drive shaft (He stated to me this only a good option if running over 450hp)
4l80e around 5K to do it right. There are some cheaper ways to do this with a manual valve body.
Gear Vendors is around 2800 + drive shaft
A change over to a manual is also around 5K and whole lot of work.

To swap gears is whole lot less expensive for most people. But yeah if you got the coin by all means OD is the way to go.

[geeteeohguy]

Over the years, things have changed. Road speeds are higher. Gas prices are higher. Most, if not all new cars have overdrives. My favorite Ponitac rear ratio for a stickshift car is 3.23. Perfect all-around gear. My favorite automatic rear ratio is a 2.93. I am running neither: I have a 3.36 in my stickshift '65 GTO and a 2.56 in my auto '67 GTO. Guess which one gets driven the most? The '67 gets about 6 times the mileage the '65 does. It cruises 80mph at under 2500 rpm, getting over 20mpg. It'll kick down into second at 85-90mph and shift hard into 3rd at 105-107 and pull like a freight train. With the stock 4oo engine. Tall gears really do well in a Pontiac powered car these days, IMO!

[HWYSTR455]

Actually, even a 'regular' rebuilt 4L80e can take a beating from a 455, it's basically a TH400 with an extra gear. In base form, from the factory, the first gen ones are rated at 440 ft lbs, a standard rebuild with reds and a little work, 600 ft lbs easy.

Takes a little more if you want to do full throttle converter lockups, but it's not required.

You can get a rebuilt unit from Hughes or B&M for $2k, less if you shop it. I've seen local trans shops offer them rebuilt for $1350. A good converter is like $500-750, depending on stall, less if you want, can get rebuilt GM units for $300-350. Summit makes cross members, application specific, for about $250, look exactly like the G-Force ones. Controller is like $350-500, depending on which you get, can find them used on ebay for a couple hundred. If you use an electronic speedo you don't need anything, a cable-x box is like $325, less if you catch one on ebay used.

So you can do one for $2500 - 3500, depending on what you get. So it's like twice as much as doing gears, diff, bearings, and setup. But the results speak for themselves.

I've seen shops offer 'budget' rebuilt trans with converters for $800-1400 range, if you're feeling lucky. Could check with a local trans shop and they would warranty it I'm sure, could always take it back if it had issues. Plenty do them, are not difficult, and as said, are basically a TH400.

http://www.ebay.com/itm/4L80E-REBUIL...6d1683&vxp=mtr

http://www.ebay.com/itm/4L80E-REBUIL...6c2e46&vxp=mtr


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[rohrt]

One member vented that its to bad a 4L80 non (E) version was not created.

Makes me wonder if such a thing could be possible for one of the aftermarket companies to create. A Universal bolt pattern case that a person could drop the guts of a normal 4L80E into and have it operate like a normal th400 but with a lockup converter option.

[HWYSTR455]

Jakes makes a 'manual' version but it's just that, manual. The thing is, electronically controlled is one of the best things about the 4L80E, can adjust shift points, firmness, lockup gear/rpm/speed/TPS, can unlock on coast, it's incredible the control you get with one. It's a shame to remove that feature.

A simple on/off lockup was one of the big problems for the non-E transmissions, lurch, jerk, hunting, all that is gone in the E versions. And it's more expensive to do a 2004R or 700 than a 4L80E these days.

The adapters these days are excellent, and there's nothing wrong with using one. But, as you see on Jake's website, there is a JW SFI bell housing that can be fitted that gives you not only whatever bolt pattern you want, but is also SFI. Shoot, even Mopar guys are using them.

Cable-X boxes came down in price, see them now new for $280 on eBay:

http://www.ebay.com/itm/Cable-X-3012...52588f&vxp=mtr

It's becoming more common and more affordable to go to a 4L80E, and once you have one, you will plant your palm on your forehead thinking "I should have done this long ago'.

And you can recoup some initial costs by selling the trans you're replacing, as well as some of the other parts.

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[rohrt]

Originally Posted by HWYSTR455

Jakes makes a 'manual' version but it's just that, manual. The thing is, electronically controlled is one of the best things about the 4L80E, can adjust shift points, firmness, lockup gear/rpm/speed/TPS, can unlock on coast, it's incredible the control you get with one. It's a shame to remove that feature.

A simple on/off lockup was one of the big problems for the non-E transmissions, lurch, jerk, hunting, all that is gone in the E versions. And it's more expensive to do a 2004R or 700 than a 4L80E these days.

The adapters these days are excellent, and there's nothing wrong with using one. But, as you see on Jake's website, there is a JW SFI bell housing that can be fitted that gives you not only whatever bolt pattern you want, but is also SFI. Shoot, even Mopar guys are using them.

Cable-X boxes came down in price, see them now new for $280 on eBay:

http://www.ebay.com/itm/Cable-X-3012...52588f&vxp=mtr

It's becoming more common and more affordable to go to a 4L80E, and once you have one, you will plant your palm on your forehead thinking "I should have done this long ago'.

And you can recoup some initial costs by selling the trans you're replacing, as well as some of the other parts.

.

You bring up some good arguments on the benefits of the computer control that I had not thought of. But I was of the mindset of an affordable upgrade option. I just looked at Jake Shoe's 4l80E Musclecar kit and it runs 4750 + shipping so we are right back to what I said. Its about 5K to do it right.

I would be all over that if I could justify it and afford it.

[Willshire]

I put a 2004r and 3.90's behind my 389. 60 mph at 2200. 3.90 compliments the 389 quite well. I could only put a 200 in the GP due to tunnel size, only slight massaging required. Used a bonneville drive shaft to make up the the distance of the 200 vs slim jim. Needs a new shaft though or balnce the Bonne one lol. Car is down for the winter so i might put a drive shaft on the xmas list

[Region Warrior]

Speed limits higher?
Ya, their back to what it was when these cars where built.
Back in the late 70's/early 80's, cruised 75-85 mph 67FB(3.36) and 68FB(3.73 with 28" tires) down the highway for hours.
Never worried about rpm.
Fuel was lot less then too...

[455rebel]

How bout a gear. Vendors overdrive. Behind the turbo 400?
It's gotta be less than 5.000.00 .

[HWYSTR455]

Originally Posted by rohrt

You bring up some good arguments on the benefits of the computer control that I had not thought of. But I was of the mindset of an affordable upgrade option. I just looked at Jake Shoe's 4l80E Musclecar kit and it runs 4750 + shipping so we are right back to what I said. Its about 5K to do it right.

I would be all over that if I could justify it and afford it.

Jake does some hard parts and mods that jack the price, as well as the tailshaft for the speedo, that's where a lot of the extra money comes in. His stuff is top notch, as is CK, but you can get away with less depending on your power level. CK with the forward drum and internal mods I think is only $2350, and if you source the rest yourself, you can get away for less.

If you collect the parts over time, adapter, cross member, controller, cable-x or speedo, and a converter, THEN buy the trans, it's not as painful as a lump-sum. They last forever. I sent mine back to CK for a freshen up on this rebuild, @ 100k miles of abuse, and it only needed frictions. Believe me when I say it was the one MOST gratifying upgrade I've ever made. Period. You will never go back.

With 373s, it's way less sensitive to tune, is awesome out of the hole and around town, and a dream on the highway. 70 is like 2500 rpm, and has a top speed of over 155. Best of both worlds. 68-72 A-bodies are no lightweights, they need gear.

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[ta man]

I came pretty close to swapping out my 3.08's to 3.42's ..but after a few long highway cruises..decided not too..my current transmission is starting to show a little too much silver in the fluid..so I have a 2.75 low gear th350 coming from Hughes maybe a good alternative for a few.I'm hoping with that and a few other minor changes my car will get into the low 11.2's this year with a highway friendly 3.08!

[HWYSTR455]

I looked hard at the gear vendors, and there were a couple things that turned me off. First, there is a service life of like 5-10k miles where you have to change the fluid. Second, the driving experience is nothing like an overdrive with a lockup, shift into OD is harsh, and you get the clunk-clunk every time you let off and get back on the throttle. It is adding length to the trans, there are tunnel mods required, generally gets in the way of X pipes, and driveline angles are more steep.

The big thing is the driving experience, and it's about the same money. But there are certain situations where it's the only option, like a big power powerglide drag cars, as an example.

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[HWYSTR455]

Originally Posted by ta man

I came pretty close to swapping out my 3.08's to 3.42's ..but after a few long highway cruises..decided not too..my current transmission is starting to show a little too much silver in the fluid..so I have a 2.75 low gear th350 coming from Hughes maybe a good alternative for a few.I'm hoping with that and a few other minor changes my car will get into the low 11.2's this year with a highway friendly 3.08!

Low gear sets help, but makes for a big gear jump on shift, some cars show det at that shift point. All you can do is back off the timing. It's still a compromise in my opinion.

And how much will the total build of the trans cost? Is the spread worth spending a touch more for an OD?

Think it was Car Craft that did a 'Junkyard Builder' series and installed a 4L80E, got the trans for next to nothing, was only the peripherals they mentioned was an 'associated cost'. Interesting read, can Google it.

If you're at a point and need to replace or rebuild a trans, that makes the choice much easier.

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[72LuxuryLeMansLa.]

Originally Posted by HWYSTR455

Low gear sets help, but makes for a big gear jump on shift, some cars show det at that shift point. All you can do is back off the timing. It's still a compromise in my opinion.

And how much will the total build of the trans cost? Is the spread worth spending a touch more for an OD?

Think it was Car Craft that did a 'Junkyard Builder' series and installed a 4L80E, got the trans for next to nothing, was only the peripherals they mentioned was an 'associated cost'. Interesting read, can Google it.

If you're at a point and need to replace or rebuild a trans, that makes the choice much easier.

.

I understand your love for that 4L80E but saying it's 'a touch more" to go from a $1500.00 TH350 to a 4L80E is a stretch.

[HWYSTR455]

Originally Posted by 72LuxuryLeMansLa.

I understand your love for that 4L80E but saying it's 'a touch more" to go from a $1500.00 TH350 to a 4L80E is a stretch.

The transmissions themselves are very close in price, especially if you include the cost of converter. At least that was my point.

As I mentioned, you approach the project as you do any other that is over X dollars, you can handle the peripherals the same, by saving and purchasing in stages. Plan it out. Live with whatever you have now and go for the big picture maybe is a way to look at it. In the long run, you spend less if you properly plan.

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[ta man]

Originally Posted by HWYSTR455

Low gear sets help, but makes for a big gear jump on shift, some cars show det at that shift point. All you can do is back off the timing. It's still a compromise in my opinion.

And how much will the total build of the trans cost? Is the spread worth spending a touch more for an OD?

Think it was Car Craft that did a 'Junkyard Builder' series and installed a 4L80E, got the trans for next to nothing, was only the peripherals they mentioned was an 'associated cost'. Interesting read, can Google it.

If you're at a point and need to replace or rebuild a trans, that makes the choice much easier.

.

For my setup cheaper than switching to a 4l80,Im happy with my highway rpms and my torque convertor..its just not the price of the transmission its everything else that has to be changed...gearing,driveshaft,crossmember...I will just settle for a car that eventually will run high tens and can cruise easily down the highway at 70 mph.