[Speargun]

I took my bird for a road trip last weekend and discovered a few things.
Local driving, which is usually 12 miles highway & 10 miles around town, then 12 miles hwy back home, I get 7-9 mpg.
Running down the interstate at 70 mph (3000 rpm) to 80 mph (3500 rpm) my fuel economy is 12 mpg, but the engine oil temperature starts to climb above 260* if I stay at speed very long. If I keep the speed at 60 or below, the oil temp stays between 210* & 240*.

I'm sure that an overdrive will help out on the highway, but I wonder how much it would help with local driving, which is what most of my driving is.

The next thing is, if you had a choice, would you go with a Gear Vendors unit or a 4L80E?

The 4L80E seems to be the simplest once installed & programmed, but the GV has the advantage of an easier install and being able to move it to another TH400 if I ever have tranny problems.

I know that I can program the shift points on the 4L80E, but I'm not very familiar with how the GV works other than you push a button to shift it into overdrive for the gear you're in.
1st -> 1st over
2nd -> 2nd over
3rd -> 3rd over
How does it downshift? (I have an auto valve body) Does 3rd over drop to 3rd at a certain rpm or does it just drop to 2nd when the trans normally downshifts?
What if I'm in 2nd over and want to go to 2nd?

I looked at the GV website and couldn't find much on the actual operation of the unit.

'67 Firebird around factory weight.
3.54 gear (May go lower someday)
275/60R 15 tires

[steve25]

What cid is your engine?

[Speargun]

Originally Posted by steve25

What cid is your engine?

455+.060
420HP & 460TQ @ the wheels

[Chief of the 60's]

Unless you have a Pro-Mod, size does not matter. Both will work well providing the tranny builder knows what he is doing. I personally do not like having the extra baggage of a GV.

[steve25]

I just wanted to double check because I had a good idea about your having a 455 cid motor by your posted oil temps as that's what I use to see on mine before I installed a remote duel oil filter bracket and a bypass oil cooler.

Those big 3.250" mains make a ton more heat even when compared to a 3,00" stroke of the 350's 389's and 400's!

At 3500 rpm with the way it seems your motor is Camed , your already getting out of the motors peak Torque band , so yes a overdrive Trans will add a lot of top end speed and extend the life of your 455's bottom end!

[Sirrotica]

The top picture is a T400 with a GV unit attached. The lower picture is a 4L80E that is just roughly 3 1/2 inches longer than a T400. The T400 with a GV unit is noticeably longer than a 4L80E. There are more advantages IMO using a 4L80E than the combined 2 units.





This image shows a T400 beside a 4L80E to give you the contrast in length.




GV has had a price increase in the last year and they may be more expensive than the 4L80E conversion at this point. One other thing is if you need internal parts for a GV unit, they will not sell anyone parts. You are required to ship the unit back for repairs and they do the labor.

A 4L80E can be worked on by most any competent shop, and parts can be easily bought anywhere in the US or online. Just some things I considered myself before making a decision on what option I was going to use on my next project.

[Chief of the 60's]

To back up what he was saying...

[ponjohn]

The 4l80e has additional benefits fully programmable shift points, firmness and a lock up converter.

These features you won't get with a t400+ GV.

[Half-Inch Stud]

Cannot keep my foot out of the GTO since running the 4L80 manual stick-shift.

2500 rpm @ 75 MPH and want to hit 100 with just a little push. Engine barely warms up after highwy OD cruise.

[ponjohn]

Originally Posted by Half-Inch Stud

Cannot keep my foot out of the GTO since running the 4L80 manual stick-shift.

2500 rpm @ 75 MPH and want to hit 100 with just a little push. Engine barely warms up after highwy OD cruise.

Turbo-clutch?

[Sirrotica]

Mark converted his 4L80E to a manual shift in lieu of using the electronic system to control it. There are kits that can be bought to accomplish this and Mark has installed one. It makes the unit full manual being that there is no automatic features about it and you must manually change gears, you still use a torque convertor and are able to use TCC lockup still also.

Link to Transgo full manual kit: http://www.transgo.com/products.php?...product_id=203

[Half-Inch Stud]

Brad, Brad, Brad, no kit involved. made my own by:

Rebuilding like a TH400 shift program.
Removed Accum duo with blocking plate (okay, a $15 "kit) <== best value purchase!
Added Vacuum Modulator ( okay that is a $100 kit, if still avail). Mandatory for Manual shift or non-puter.
Added Mech Speedo (not manual Speedo tailcups at the time)
Mechanicals

Back to Topic; 4L80 was/is the right choice vs GV OD chunk or Mainshaft/Countershaft boxes.

****** Should have installed the 4L80 build 6 years ago when i build em. ******

[ponjohn]

Originally Posted by Sirrotica

Mark converted his 4L80E to a manual shift in lieu of using the electronic system to control it. There are kits that can be bought to accomplish this and Mark has installed one. It makes the unit full manual being that there is no automatic features about it and you must manually change gears, you still use a torque convertor and are able to use TCC lockup still also.

Link to Transgo full manual kit: http://www.transgo.com/products.php?...product_id=203

Then why the clutch pedal?

[brooknice]

I have the gear vendor and I love it. I melted my 400 and it had no affect to the gv. The 400 that in the car came with the car. I didn't want to have more extra stuff laying around the garage. No issue with gv. I just like the idea of still having the original 400. I got my original engine on a stand in the corner of my garage. Just think if I would have melted the 4l80 that would have cost me a arm and a leg. GV get my vote.

[Ben M.]

4L80E in my vote. The Gear Vendors is a nice unit, but the amount of fluid changes they called for and the expense of the unit made it not something I wanted to consider. Users of it I have talked to weren't thrilled with the shifting of it either in some cases. The 4L80E is easier to acquire and find parts for, plus with a '91-93 GM 6.2-6.5 diesel 3/4-1 ton truck you can get a standalone controller for next to nothing.

I'm acquiring the parts for the conversion of my '73 wagon with a 4L80E.

[Sirrotica]

Originally Posted by Half-Inch Stud

Brad, Brad, Brad, no kit involved. made my own by:

Rebuilding like a TH400 shift program.
Removed Accum duo with blocking plate (okay, a $15 "kit) <== best value purchase!
Added Vacuum Modulator ( okay that is a $100 kit, if still avail). Mandatory for Manual shift or non-puter.
Added Mech Speedo (not manual Speedo tailcups at the time)
Mechanicals

Back to Topic; 4L80 was/is the right choice vs GV OD chunk or Mainshaft/Countershaft boxes.

****** Should have installed the 4L80 build 6 years ago when i build em. ******

Sorry Mark, I thought you bought a kit, my misunderstanding, anyway there are kits available.

Rossler has a black box that can make a 4L80E manual also by just connecting it to the connector on the side of the transmission and running 12 volts to it. The writeup says that the pan doesn't need to come off just hook up the box. The shifts it says are firm, because it uses full pump pressure, and pump life could be shortened because of that.

Link to Rossler black box article in Hot Rod magazine:https://www.hotrod.com/articles/junk...transmissions/

Myself, I already own a 93 diesel dually with the standalone ECM and I have a spare, but the GM standalone is of course non programable and it also requires more sensors to be installed on the engine to work, one size fits all. I should also mention that my 4L80E in my diesel dually has lived a tough life and is still doing well at 270,000 miles. If you're looking for durability I can only look at what this transmission has survived as built from GM.

For my next project car I'm going to go with the US Shift/Bauman electronics controller $565 for the ECM and $120 for the plug and play harness, easier to hookup less sensors required and pretty much state of the art for transmission controllers. Lots of adjustability without having to use a laptop for programming.

Link to US Shift controller: https://www.usshift.com/usq4.shtml

To address the breakdown of a T400, and a 4L80E as far as rebuilding one, 75% of the T400 internal parts interchange with the 4L80E so rebuilding one is going to be right in the same dollar amount along with comparable labor costs. Saving any appreciable amount of money rebuilding a T400 over a 4L80E is pretty much a non issue.

A mildly modified 4L80E is going to handle 750 HP/TQ so if done properly the transmission should last many years even being used with slicks on a dragstrip, not many street driven cars on this forum in the 750 HP range, there are a few, but not very many in that territory. If you're in the over 750 HP/TQ range building a 4L80E to withstand that much power is not cost prohibitive up to 1000 HP.

I've considered a whole bunch of different O/D scenarios for my next car and of all the lighter duty transmissions that need every part internally changed to a billet part, to GV, Borg Warner OD, and Hone-o-drive add on units the 4L80E is the best bang for the buck of all of the options I considered for myself anyway.

If you look at the other Brand X applications there are a whole bunch of LSX cars, BBC cars, and even some non GM brands that are using the 4L80E for a durable reasonably priced OD transmission. Also lots of 4L80E cores as they were used in GM trucks from 1991 through 2013 so they aren't in short supply at all.

[Formulajones]

It comes down to what you have to start with.

I find most people that already have a nicely built 400 with a $1,000 converter in it, don't want to invest in that all over again going with the 4L80.
But with the deals that are out there right now, they look pretty good.

Monster Transmission has a sale right now for a complete kit, fresh 4L80 complete conversion kit with controller for $3,000 rated to 500hp and comes with a mild stall converter (2,000 rpms), and the trans can be built to various power levels up to over 1,000hp and tq for added cost. Standard version of their transmission is only rated to 325hp and 300 tq so the kit they are selling now is already one of the upgraded transmissions (middle of the pack).
If you need more converter, and most builds I do here need more, custom stalls are done at extra cost. Some may just prefer to have their own favorite converter company build a converter for them.

But to get into one with a complete kit for $3000 with all brand new stuff is a pretty good way to go.

[Half-Inch Stud]

Originally Posted by ponjohn

Then why the clutch pedal?

Locking Converter, and a bypass switch to be full time converter mode.

[Half-Inch Stud]

Originally Posted by Formulajones

It comes down to what you have to start with.

I find most people that already have a nicely built 400 with a $1,000 converter in it, don't want to invest in that all over again going with the 4L80.
But with the deals that are out there right now, they look pretty good.

Monster Transmission has a sale right now for a complete kit, fresh 4L80 complete conversion kit with controller for $3,000 rated to 500hp and comes with a mild stall converter (2,000 rpms)..... to get into one with a complete kit for $3000 with all brand new stuff is a pretty good way to go.

oh heck no. That's $1800 above DIY reality. Most i have in my deal is $280 for the shorter 1350 yoked driveshaft (Houston Driveline Services)

$70 4L80 with truck Converter &dipstick tube.
$108 Vac Mod kit.
$15 Accum block off plate
$70 G&R kit for 4L80
$200 for mech speedo, and $20 for longer cable
$8 & $12 for the stupid cooling line clips and retainers.
$23 for a gallon of Type F
$280 for driveshaft with 1350s and yoke.

[Formulajones]

Not do-it-yourself NEW everything.

Of course a junkyard swap would be cheaper, but that's not how a majority of the classic car world is going to do it. Least not around here anyway.

I certainly won't be putting used tranny stuff behind a 600+ hp street car that has thousands in the rest of the drivetrain already.

$3000 is cheap for a complete swap, brand new, with a new lock up stall converter, and a controller, which in my opinion is the way to go when doing one of these things. Consider the 5 speed manual world, where even a car that is already a 4 speed still needs $4,000 worth of parts to do the swap, makes this 4l80 auto overdrive swap cheap.

Most of the stuff I do around here anyway isn't going to work with a stock truck converter, and no one wants to have to shift the darn thing all the time either. Electronic control is friggin awesome. No other way to explain it. Push a few buttons and you can make the transmission do anything you want, when you want, how you want, and never get your fingers dirty doing it.