[torqhead]

Originally Posted by sjdiesel

I swapped in a 4l80e in my 1967 GTO and love it! I bought mine from Vons Transmissions in San Bernardino and bought a torque converter from Tri Shield Performance. I used a USShift controller that works great! Super easy to hook up and tune. I was running a quadrajet so had to buy a TCI throttle position sensor. No big deal.

The install is pretty easy. I opted to purchased a replacement crossmember that fit perfectly! Also did a Dakota digital digital to mechanical speedo converter.

A must is these cooler line banjo fittings. That is probably the tightest part of the trans tunnel and the banjo fittings make it possible. I bought these, some stainless 5/16 tubing and a couple AN fittings. I bent them up to come out in the same location as my TH400 cooler lines did from the factory. Cut my factory cooler lines, installed AN fittings and it works perfectly!

https://www.ebay.com/itm/6AN-x-1-4NP....m46890.l49292

Here’s a list of parts I put together before I did my swap:
Transmission
converter
Dipstick
Remote TPS (TCI 377450)
USShift Quick 4 & harness
Trans crossmember (RCAE-4)
Shiftworks brackets
Cooler fittings
Stainless Cooler tubing
Trans fluid
Dakota digital Mechanical speedo converter
Driveshaft

BTW I am selling my USShift controller and TPS because I am switching over to EFI and the Holley system has all the trans controller stuff. PM me if you’re interested.

Sean, thanks for all the great info! I really like the nice job you did with the cooler lines and will steal that idea! I'll PM you.

[JLMounce]

I just wish the 4l80 had a taller overdrive. With a 3.73 axle and a 26” tire you’re still close to 3000 rpm at 75 mph. I can get decently close to that by doing a low gearset in my th400 and swapping to a 3.08.

This is one of the things that drove me to having a 4l60e built. I’ve never installed it though simply because of these threads. I just don’t know how it’ll hold up, if at all.

[Sirrotica]

Originally Posted by JLMounce

I just wish the 4l80 had a taller overdrive. With a 3.73 axle and a 26” tire you’re still close to 3000 rpm at 75 mph. I can get decently close to that by doing a low gearset in my th400 and swapping to a 3.08.

This is one of the things that drove me to having a 4l60e built. I’ve never installed it though simply because of these threads. I just don’t know how it’ll hold up, if at all.

The difference between the two transmissions is 5% that takes you from 3000 RPM down to 2850 RPM. Is it going to make that much difference for the tradeoff of strength?

There are plenty of chevy/LS guys that will probably buy the newly rebuilt 4L60E transmission from you.

The difference is wear factor, the 60 wears much quicker than the 80, all things being equal, same goes for the other automatic ODs, which I won't name. One wears quicker than the other just due to the engineering designed into the original transmission. Even if there isn't a catastrophic failure, the clutch/band surface area is much more from the start. I already posted the 4L80E was designed for up to 18,000 lb vehicles, no other GM OD has anywhere near that GVW rating.

[torqhead]

Originally Posted by JLMounce

I just wish the 4l80 had a taller overdrive. With a 3.73 axle and a 26” tire you’re still close to 3000 rpm at 75 mph. I can get decently close to that by doing a low gearset in my th400 and swapping to a 3.08.

This is one of the things that drove me to having a 4l60e built. I’ve never installed it though simply because of these threads. I just don’t know how it’ll hold up, if at all.

I know we talked about this a few years ago and I was still trying to have faith in what I was being told by some of the "best builders" in the business. You might recall one of them, Performabuilt, sent me two that ended up being POS' from the get go. Those two I didn't include when I said 4. these were actual failures post initial install and operation. The last one built was done correctly, it just took out the weak link.

I kind of wish I knew more about the internals sooner as I probably would have bailed a while ago. I've seen post that indicated the 4L60 wasn't up to snuff, but don't ever recall anyone taking the time to explain the weak point, hence why I put it on the post. Every bit of power from the motor to the rear wheels goes through that "weak link" part. Ironically it failed when it hit 3rd gear on a decent pull even though it was on street tires. Amazing I didn't strip it out when we were at Bandimere in Sept

I'm running a 29" tire which helps on RPM...

[pastry_chef]

Originally Posted by torqhead

Performabuilt

Performabuilt one of the best?
LMFAO.
I guess some are easily swayed by verbal claims, marketing etc. Many out there talk about being great. Very very few are.

[68lemans462]

You have blown up 6 of these! Good god Dave you have more patience than I do! That 455 is making some good power.... Let me know if you need a hand with the install. At the least I'm good at bringing a bottle of whiskey and a bad joke! Happy new year bro!! -Dan

[torqhead]

Originally Posted by 68lemans462

You have blown up 6 of these! Good god Dave you have more patience than I do! That 455 is making some good power.... Let me know if you need a hand with the install. At the least I'm good at bringing a bottle of whiskey and a bad joke! Happy new year bro!! -Dan

Happy new year Dan! Well yes there were a total of 6 remove/installs but two of them were the perfromabuilt's that one made it a couple of miles and smoked and the second dropped a valve supposedly in it's maiden voyage about 15 miles into the test trip, had to limp home in 2nd gear.

You know I'm always up for a whiskey!

[Formulajones]

Originally Posted by JLMounce

I just wish the 4l80 had a taller overdrive. With a 3.73 axle and a 26” tire you’re still close to 3000 rpm at 75 mph. I can get decently close to that by doing a low gearset in my th400 and swapping to a 3.08.

This is one of the things that drove me to having a 4l60e built. I’ve never installed it though simply because of these threads. I just don’t know how it’ll hold up, if at all.

I'm with ya on the overdrive ratio. Don't know why GM decided on the .75 overdrive for this trans and it's a bit of a bummer, but the end result will still be worlds better on both ends of the spectrum than a 3.08/turbo 400 setup.

The one I'm doing now has 4.10's with a 28" tire, and I've had the car that way since 1987. So even a .75 overdrive with a lockup converter will be a welcome addition and night/day difference from what I'm used to. Right now 65 mph is 3400 rpm. With a .75 and lockup, I'll be at 2400 rpm. I can now easily cruise 70 mph at 2600 rpm, and push 75 if I want with no trouble, and I'm okay with that.

However the .75 overdrive never swayed me a bit in making a transmission decision for this particular car. I'll take the durability, the lockup converter, and the fact that an electronic controller can now precisely control shift points as all added benefits too. It'll be nice at the track to just let the trans do it's thing, lock up the converter in any gear and experiment with the different possibilities, and all the while not worry about breaking this thing.

[72projectbird]

Originally Posted by JLMounce

I just wish the 4l80 had a taller overdrive. With a 3.73 axle and a 26” tire you’re still close to 3000 rpm at 75 mph. I can get decently close to that by doing a low gearset in my th400 and swapping to a 3.08.

This is one of the things that drove me to having a 4l60e built. I’ve never installed it though simply because of these threads. I just don’t know how it’ll hold up, if at all.

That's what I've been hung up on too. Right now I run a TH350 and a 3:23 with a 28" tall tire, and it's not bad at all on the highway. Switching to a 4L80 would be great if I leave the rear gear in it, but any steeper and you start losing the advantage of OD.

I've been toying with the idea of a 6L90. Obviously that's a whole different game than swapping in a 4L, but it might be worth it when done.

[JLMounce]

Originally Posted by 72projectbird

That's what I've been hung up on too. Right now I run a TH350 and a 3:23 with a 28" tall tire, and it's not bad at all on the highway. Switching to a 4L80 would be great if I leave the rear gear in it, but any steeper and you start losing the advantage of OD.

I've been toying with the idea of a 6L90. Obviously that's a whole different game than swapping in a 4L, but it might be worth it when done.

Yeah the more and more that I think about it. To get the torque handling I need with the performance ratios I’m after and an OD tall enough for comfortable long distance highway driving pretty much pushes me towards an auto to manual swap.

The TKO600, new TKX and the Magnum T56 all do exactly what I need with the rear ratio and tire sizes I already run.

I may price those as well as total cost of doing a low gearset 4l80 and reducing the gear ratio in the rear.

It’s kind of too bad I already had the 4l60 built and purchased a custom billet converter for it already.

[Formulajones]

Originally Posted by JLMounce

Yeah the more and more that I think about it. To get the torque handling I need with the performance ratios I’m after and an OD tall enough for comfortable long distance highway driving pretty much pushes me towards an auto to manual swap.

The TKO600, new TKX and the Magnum T56 all do exactly what I need with the rear ratio and tire sizes I already run.

I may price those as well as total cost of doing a low gearset 4l80 and reducing the gear ratio in the rear.

It’s kind of too bad I already had the 4l60 built and purchased a custom billet converter for it already.

I looked at the stick option really hard for myself and this particular car I'm doing now. Even went through with 3 different quotes.

I ran into a few other issues though. For starters the auto to manual TKX swap is a bit more money. While that's not a huge deal breaker, what really stopped me was the torque rating. It's borderline for the car I'm doing the swap in with the current engine, and definitely not enough for the new engine.

So I figured I better do a Magnum 6speed but the cost jumped another $1500 to the point I finally had to say that's just too much money. So I skipped the manual idea for this car.

I suppose with the .75 overdrive causing contemplation, one could keep a more reasonable rear gear in the car if you had enough engine, looking at it from a track performance standpoint.
Mine has been setup around the 4.10's for more than 30 years, I like how the car acts, performs, 60 foots, etc... and the rpm I cross the finish line is perfect with my 28" tire so I'm not 100% on board with changing it but not against the idea. With the new engine at a later date I might pull it back to a 3.73 at the most.
That would be about perfect, 2500 rpm is 75 mph cruising. I'll do that all day long.

The only difference I see between mine and your combo (if I do 3.73's) is the really short tire your running. Your 26 inch to my 28 is worth 4 mph all by itself.
Which is why 3.73's and the .75 overdrive looks good in my setup compared to yours.

[Sirrotica]

Most late model factory high performance cars shoot for roughly a 3.50 axle with a .75, or a .70, OD transmission, and low profile tires. You can get too far into a situation with tall gears where the TCM is locking, and unlocking the clutch on the convertor, and jumping between 3rd and 4th, pulling a load, or encountering a grade.

I recently pulled a small 4X8 U Haul trailer from Phoenix to Ohio, with a .70 OD and a 3.29 axle, it was miserable pulling grades and trying to accelerate without it dropping either the torque convertor clutch in, and out, or hunting for gears between 3rd and 4th. It also killed fuel mileage especially in states with any mountains. Flat level roads it was fine, but unsuited for even a light load, or grade.

My 05 GTO with.70 OD, and a 3.46 axle would have been much better suited for the chore, and I have towed a bunch of trailers with my GTO, and it does work well, with or, without a load, with the 3.46 gear. I believe GM got the gearing right for most situations in my GTO.

I have plenty of vehicles with a .70 OD, and 2 with the .75 OD, I can't discern any big difference between either ratio. Close enough that other than 150 RPM difference at 70 MPH looking at the tach, you're hard pressed to know which transmission is in the vehicle you're driving. I just don't see that 5% as a huge disadvantage, or a deciding factor for not using a stronger transmission. Especially when most of these cars aren't after every last MPG they can squeeze out. Mostly to keep the engine together longer, and lose a lot of engine noise at highway speeds, making the car much more enjoyable to drive on the highway.

Just thinking about the GM trucks that used both transmissions with respective .70, and .75 OD, they didn't specify different ratios depending which transmission the truck used. Most common ratios were 3.42, 3.73, and 4.10, there were a few other ratios, but these were the main ones used with either OD transmission. Ratio was mostly dictated by intended maximum payload, and what was under the hood, not the OD ratio. On the other hand the NV4500, stick transmission has a .73 OD, so nearly right between both of the OD automatics, and it also used the common axle ratios.

Next project will have a 3.50 gear with a 4L80E transmission, 455 84 GP. I doubt I'll worry about 150 RPM difference at 70, at all. Keeping the locking feature on the convertor will cancel out 100 RPM, only looking at a 50 RPM split at that point.

[Half-Inch Stud]

Been enjoying the 4L80 behind the 470 PMD.
Recommend 4L80 due to TH400 pedigree with OD and improvements. Obvious.

I think you can get lucky enjoying the factory Gasoline Converter as-is. Diesel converter i dunno.
Promised meself a 2-clutch high stall 4L80 converter, but NOT Needed. Think i saw 25 rpm and maybe 50 rpm drop for unlock-to-lock at highway cruise.

If you can find the Vacuum Modulator kit $100-$130 then you can be confident in manual-shift approach. I did, and would never add a processor. Shifting is stupid optional with a 455, but hey i like 1st gear and like to fast-flick to 2nd. In 3rd pretty quick (like a TH400). So pulling away in 2nd or 3rd becomes a feel-like-it choice..

Be sure to get a 4L80 with "TH400 location" cooling line pair. The other case type puts cooling line back too far to enjoy connecting. Yet, also be sure to get a 4L80 Core that has not been cooked. Coworked got a nuclear-brunt unit that melted-fragged the rear planets from driving home in 2nd gear for 1/2 hour.

[Formulajones]

Originally Posted by Half-Inch Stud

Be sure to get a 4L80 with "TH400 location" cooling line pair. The other case type puts cooling line back too far to enjoy connecting. Yet, also be sure to get a 4L80 Core that has not been cooked. Coworked got a nuclear-brunt unit that melted-fragged the rear planets from driving home in 2nd gear for 1/2 hour.

The banjo fittings that are on the market now solve the issue of hooking up the rear trans line in these retro swaps. I think someone even linked to it later after I mentioned it in my first post.

These days, if you buy from a quality builder, you don't even have to worry about rear planetary lube on the older units with both cooler lines up front. Places like Hughes and Jakes, and I'm sure others now, modify these older cases for better rear lube making the desire for the newer rear lube case unnecessary.

However you still have the choice of either case with various builders if you wish. I'm dealing with Hughes, and decided on the older case with both cooler lines up front, with no additional cost for the case mods to improve rear lube. It just simplifies the cooler line install without the need to buy the banjo fittings. The other benefit is that it has the shorter shift selector shaft too making linkage or cable hookups a bit easier/cleaner. The later model rear cooler line units started also putting the neutral safety switch on the selector shaft making the shaft longer. That wasn't needed in my application since my neutral safety is on the floor shifter itself. So one less thing to plug in on the transmission too.

Just a lot of little things to consider that most probably don't concern themselves with.

[Chief of the 60's]

I fully understand the functions and reasons for a lockup but many experienced OD builders are totally against a lockup converter in a tranny used for racing. Many of those same builder are also against a tranny brake in an OD.

[Formulajones]

Originally Posted by Chief of the 60's

I fully understand the functions and reasons for a lockup but many experienced OD builders are totally against a lockup converter in a tranny used for racing. Many of those same builder are also against a tranny brake in an OD.

I'm yes and no on that subject for a lot of reasons why that are too lengthy to discuss. The only way I'll even consider an automatic overdrive is with a lockup converter, but that is with electronic control. Just to hit on one reason why.....

Pretty much everything I do here requires some sort of custom stall converter. Then couple in the fact that most places have a hard time building an efficient one that couples nicely, and lord knows we've had plenty of threads about that around here so that's been very well discussed.

So my issue is having that overdrive ratio drop the rpm another 600-800, with a converter that is really not efficient enough to begin with, then you have a very loose/mushy feeling at low rpm cruising that for me, isn't enjoyable at all and not what I want in a car, and most of the swaps I do here for people don't want that either.

I've dealt with Continental for years that built me very nice efficient converters right up until they went out of business, and lately Cliff has been extremely helpful with a new company in getting converters dialed in for me as well. But having a lockup feature just goes a long way in taking that variable out of the equation, even though I still prefer an efficient converter for other reasons too long to explain.

However with that said, I really only prefer the lockup features if they are electronically controlled, and that is the key. If you're doing a cable version of the overdrive, then I would lean more towards a very efficient converter as a MUST and skip the lockup feature. It's a real pain in the butt to dial in a livable lockup range on cable operated transmissions when you start getting into the performance end of things. So the 700's, 200's, AOD's, I'd probably avoid the lockup using it behind a performance engine. Electronic control however is a whole new ball game.

[Chief of the 60's]

Originally Posted by Formulajones

I'm yes and no on that subject for a lot of reasons why that are too lengthy to discuss. The only way I'll even consider an automatic overdrive is with a lockup converter, but that is with electronic control. Just to hit on one reason why.....

Pretty much everything I do here requires some sort of custom stall converter. Then couple in the fact that most places have a hard time building an efficient one that couples nicely, and lord knows we've had plenty of threads about that around here so that's been very well discussed.

So my issue is having that overdrive ratio drop the rpm another 600-800, with a converter that is really not efficient enough to begin with, then you have a very loose/mushy feeling at low rpm cruising that for me, isn't enjoyable at all and not what I want in a car, and most of the swaps I do here for people don't want that either.

I've dealt with Continental for years that built me very nice efficient converters right up until they went out of business, and lately Cliff has been extremely helpful with a new company in getting converters dialed in for me as well. But having a lockup feature just goes a long way in taking that variable out of the equation, even though I still prefer an efficient converter for other reasons too long to explain.

However with that said, I really only prefer the lockup features if they are electronically controlled, and that is the key. If you're doing a cable version of the overdrive, then I would lean more towards a very efficient converter as a MUST and skip the lockup feature. It's a real pain in the butt to dial in a livable lockup range on cable operated transmissions when you start getting into the performance end of things. So the 700's, 200's, AOD's, I'd probably avoid the lockup using it behind a performance engine. Electronic control however is a whole new ball game.

Maybe I'll just make my next build a Clutchflite

[Formulajones]

Originally Posted by Chief of the 60's

Maybe I'll just make my next build a Clutchflite

Old school is good with me!!

[Stan Weiss]

Will a 6L80 fit?

Stan

[Formulajones]

Originally Posted by Stan Weiss

Will a 6L80 fit?

Stan

My fathers truck has one of those, they are enormous transmissions lol. About the size of the Allison in my duramax.

Another option I've seen, but it's not cheap, are some places offering 6 speed conversions in the 4L80E cases. It's like a $6000 transmission though.