Auto trans decision help for my new LSx build

[derotoreut]

Hey guys, I am beginning work on my first frame off with LSx install on a 71 SWB. I'm having a custom chassis built by Scott's Hot Rod. I haven't determined my exact engine yet, but I plan to look for a new GM engine/trans package. I decided to go with an automatic transmission and Scott's recommended setting up the chassis for a 4L60e transmission. Can you give me any insight on if this is a good way to go? from what little I know, it sounds like the 4L80e is a stronger transmission, but may be bigger and heavier. What are my options, and what would be a good way to go? Right now I am considering possibly new LS2 or LS3 engine/auto trans combo. Please help me with my auto trans options, so I am able to get the chassis set up properly. I will need to get back with them before they move too far along with fabrication. Thanks.

[clinebarger]

4L80E, If you already had a 4L60E I would suggest upgrading it. But your early in your build....

[l92powered77]

my friend would you rather hunt water buffalo with a .22 or a .50 bmg ????

i thought so .50 bmg all the way and that is the 4l80e....

4L80E and never worry about the tranny unless you pushing ridiculous power....

post pics of your build and whatever drivetrain you end up buying! take it easy

[derotoreut]

Hmm… I wonder why Scott's would recommend using a 4L60e. They said it's bullet proof and usually used on these builds. I guess I will continue researching. Thanks for the comments. Keep the feedback and opinions coming please.

[slotard]

A built 60 can be very strong, but a factory one might be lacking. The setup I'm looking at sadly comes with a 60, so I'll probably get it going with that and then if anything happens (or if I add any power) I'll swap to an 80.

The size/weight difference is there, but it isn't a big deal in a truck.

One advantage of the 60 is gearing, it has a lower 1st gear and a higher overdrive.

[homemade87]

Originally Posted by derotoreut

Hey guys, I am beginning work on my first frame off with LSx install on a 71 SWB. I'm having a custom chassis built by Scott's Hot Rod. I haven't determined my exact engine yet, but I plan to look for a new GM engine/trans package. I decided to go with an automatic transmission and Scott's recommended setting up the chassis for a 4L60e transmission. Can you give me any insight on if this is a good way to go? from what little I know, it sounds like the 4L80e is a stronger transmission, but may be bigger and heavier. What are my options, and what would be a good way to go? Right now I am considering possibly new LS2 or LS3 engine/auto trans combo. Please help me with my auto trans options, so I am able to get the chassis set up properly. I will need to get back with them before they move too far along with fabrication. Thanks.

You did not mention what your goals are and how you will be using the truck . This will make a big difference on which way we need to steer you . If it is basically a driver with some spirited street driving and a occasional tow the 4l60e will be fine . Of coarse with a good trans tune and a good trans cooler .

If you are beating on it and taking it the track regularly the 4l80e may be a better choice .

If buying a new trans you may look into a 4l60e or 4l70e from finish line transmissions . They have several different levels of builds . I have there level five . This may also be a little easier to set up with a stock pcm . It was a plug and play for me with my 04 truck operating system . This option would not cost that much more than a stock trans new .

If you do use a stock 4l60e and have problems just get it built to suit your need down the road . I have seen people beat on the stock ones pretty bad and they are still holding on. The key is get it tuned to help it survive and a trany cooler. Heat is mostly what kills them during performance .

[tinydb84]

If you can afford a custom chassis then I would say pay a few extra bucks to go with a 4l80. You wont have to worry about it going out and you can do everything a 4l60 could. If you plan on going overkill with the engine then take a look at Jake's Transmissions.

[derotoreut]

Originally Posted by homemade87

You did not mention what your goals are and how you will be using the truck . This will make a big difference on which way we need to steer you . If it is basically a driver with some spirited street driving and a occasional tow the 4l60e will be fine . Of coarse with a good trans tune and a good trans cooler .

If you are beating on it and taking it the track regularly the 4l80e may be a better choice .

If buying a new trans you may look into a 4l60e or 4l70e from finish line transmissions . They have several different levels of builds . I have there level five . This may also be a little easier to set up with a stock pcm . It was a plug and play for me with my 04 truck operating system . This option would not cost that much more than a stock trans new .

If you do use a stock 4l60e and have problems just get it built to suit your need down the road . I have seen people beat on the stock ones pretty bad and they are still holding on. The key is get it tuned to help it survive and a trany cooler. Heat is mostly what kills them during performance .

You're right, I forgot to mention that this build is basically for a weekend driver, cruise and show truck. This will NOT be a daily driver or autocross driven truck. I will want to be able to drive this truck to shows such as Syracuse Nat'ls or maybe Columbus Goodguys show too. Now with that being said, I will most likely be looking at an LS2 or LS3 with some mods to the engine and will still want to enjoy this truck. When I want to get on it, I want to be able to have fun without any reservations.

[Wasted Income]

I've personally destroyed more 4L60s at moderate power than I care to recall. If you are making any sort of power, and keep it on slippery tires, it might last a bit.

If you have the choice, set it up for a 4L80E and call it a day.

Originally Posted by clinebarger

4L80E, If you already had a 4L60E I would suggest upgrading it. But your early in your build....

Not sure if serious? Did you change your tune, Cline? haha j/k.

[BR3W CITY]

HAHAHA I was gonna point that out. Cline not championing the 4l60e!?! I gotta go buy a lottery ticket.


The cool part about the 4l60e is that they tend to fail in SPECTACULAR fashion.

[clinebarger]

Originally Posted by Wasted Income

I've personally destroyed more 4L60s at moderate power than I care to recall. If you are making any sort of power, and keep it on slippery tires, it might last a bit.

If you have the choice, set it up for a 4L80E and call it a day.



Not sure if serious? Did you change your tune, Cline? haha j/k.

Originally Posted by BR3W CITY

HAHAHA I was gonna point that out. Cline not championing the 4l60e!?! I gotta go buy a lottery ticket.


The cool part about the 4l60e is that they tend to fail in SPECTACULAR fashion.

I still really like 4L60E's....I can build one to handle a big cam LS3 in a heavy car with drag radials

But money wise....Since he has not yet bought a trans or the Chassis set-up, The 4L80E would be a wiser choice.

This car finally broke the 4L65E that I built a few years ago, The Output shaft broke at the input planet, But at well over 500 passes & hard street driving, The rest of the unit looked good!

Another customers '05 Silverado SS, LQ9 with a L92 top end, Cam & long tubes has been beating on his stock w/ a good converter 4L65E for a couple years now, The truck had 100K on it when the engine mods were done.

Now to eat some crow.....Customer brings in a '84 Chevy C-10 Cammed LQ4 with 3-4's out of the 4L60E, Burned up 3 of my transmissions in 2 months. Took a ride with him driving on the 4th trans, Completely abusive/No driving prick....3-2, 2-3, 3-2, 2-3, 3-4, 4-2 over & over again, I thought. his foot would cramp up. He was overheating the 3-4 clutches on purpose in my opinion...............However I told him I can build a trans to hold up.
I installed a 4L80E 100% out of my pocket, That hurt!

[derotoreut]

I spoke with Justin at Scott's Hot Rod and asked him if they could provide a transmission crossmember that would accept both 4l60 and 4l80. He said they've never done that before. They've only provided mounts for either one or the other, but they agreed to provide one that would accept both. That takes the pressure off me, at least for the time being.

[l92powered77]

Hey man thats good to hear that the company is willing to accommodate your need. Good luck on build, i too have crossmember issues.. Ls swap learning curve!

[BR3W CITY]

Originally Posted by derotoreut

I spoke with Justin at Scott's Hot Rod and asked him if they could provide a transmission crossmember that would accept both 4l60 and 4l80. He said they've never done that before. They've only provided mounts for either one or the other, but they agreed to provide one that would accept both. That takes the pressure off me, at least for the time being.

don't let them fool you. The only difference is that the trans mount has two holes instead of one. To make the crossmember accept both, all it takes is a drill, and the correct mount from the parts store....unless they are planning on building something that has the rubber mount built in (strange).

[tinydb84]

Originally Posted by BR3W CITY

don't let them fool you. The only difference is that the trans mount has two holes instead of one. To make the crossmember accept both, all it takes is a drill, and the correct mount from the parts store....unless they are planning on building something that has the rubber mount built in (strange).

Maybe they meant the placement of the crossmember in relation to the motor mounts.

[Wasted Income]

Originally Posted by clinebarger

I still really like 4L60E's....I can build one to handle a big cam LS3 in a heavy car with drag radials

But money wise....Since he has not yet bought a trans or the Chassis set-up, The 4L80E would be a wiser choice.

This car finally broke the 4L65E that I built a few years ago, The Output shaft broke at the input planet, But at well over 500 passes & hard street driving, The rest of the unit looked good!

Another customers '05 Silverado SS, LQ9 with a L92 top end, Cam & long tubes has been beating on his stock w/ a good converter 4L65E for a couple years now, The truck had 100K on it when the engine mods were done.

Now to eat some crow.....Customer brings in a '84 Chevy C-10 Cammed LQ4 with 3-4's out of the 4L60E, Burned up 3 of my transmissions in 2 months. Took a ride with him driving on the 4th trans, Completely abusive/No driving prick....3-2, 2-3, 3-2, 2-3, 3-4, 4-2 over & over again, I thought. his foot would cramp up. He was overheating the 3-4 clutches on purpose in my opinion...............However I told him I can build a trans to hold up.
I installed a 4L80E 100% out of my pocket, That hurt!

I don't doubt that you build one badass 4L60E. However, I would not want to be on the paying end of that bill.

For my budget, it's hard to beat a $200 junkyard 80e with a $120 HD2 and a nice converter.

[derotoreut]

Originally Posted by BR3W CITY

don't let them fool you. The only difference is that the trans mount has two holes instead of one. To make the crossmember accept both, all it takes is a drill, and the correct mount from the parts store....unless they are planning on building something that has the rubber mount built in (strange).

How can you say that just a drilled hole is the only difference on a custom built chassis? Besides there's a 4-1/4" difference from front of BH to mount between the 60 and 80. They're planning to locate the trans mount in the proper relation to LS motor mounts, plus making it able to accept either 4l60 or 4l80; at no cost to me. No fooling involved.

[Wasted Income]

I think you're making it into something bigger than it is. Brew is not wrong. It may just be as simple as flipping the trans crossmember 180* in the frame to make up that 4-1/4". At the VERY MOST, it would involve welding an extra set of tabs to the frame to accomodate a different position for the trans crossmember. This is of course assuming that they make the trans crossmember removable. I'd hope that would be the case on a high dollar kustom built chassis like that.

[Gooker928]

Originally Posted by Wasted Income

I think you're making it into something bigger than it is. Brew is not wrong. It may just be as simple as flipping the trans crossmember 180* in the frame to make up that 4-1/4". At the VERY MOST, it would involve welding an extra set of tabs to the frame to accomodate a different position for the trans crossmember. This is of course assuming that they make the trans crossmember removable. I'd hope that would be the case on a high dollar kustom built chassis like that.

I agree. I rotated my original crossmember 180 degrees and drilled a hole to make my 6l80e fit.

[slotard]

Regarding crossmember...

I currently have 350/350 and will probably go to 4.8/4L60 with a possible upgrade to 4L80 down the line. What will I need to do for tranny mounts?

[Wasted Income]

Unbolt...slide to new location....drill new holes....do burnouts.

[derotoreut]

I'm not sure how I would flip the transmission mount on a custom made chassis. Any ideas?

[elimontfort]

I would ask the fabricator to make that a bolt in crossmember. You said it's just gonna be a cruiser plus when that 4l60 eats it it'll be a lot easier to swap the trans.

[slotard]

Originally Posted by Wasted Income

Unbolt...slide to new location....drill new holes....do burnouts.

I'm guessing the factory crossmember is riveted, so I'll have to grind them off, but if that's the basic procedure it doesn't sound too bad. How far back will I have to slide it?

[Wasted Income]

Originally Posted by derotoreut

I'm not sure how I would flip the transmission mount on a custom made chassis. Any ideas?

Here, let me draw you a picture...

Unbolt at 1 and 2, and either flip it 180* as shown in step 3, or make a new piece to bolt in to location 1 and 2. How's that for an idea?