LS2 4l65e dead.. rebuilt or go 4l80e?

Patobusta

Not-quite-so-new-guy
Jul 2, 2017
20
3
I just finished swaping an 2005 GTO lS2 4l65e driveline to my monte, and unfortunately the transmission is gone.. it just wont get into 3rd.
Now theres the decision, rebuilding the original 65e? or going 80e?

What are the pros and cons?

To me an 80e will always be stronger, and I believe it fits nicely, but some uneducated comentaries I heard about it been "heavier" meaning both mass and internal friction that might reduce the aparent power of the engine, and also the gearing of the 80e being "longer" than the 65e specially on 1-2, thus reducing the aparent excitement of the engine/car.

Do you guys agree? any experience with both of them?

Thanks!
 

64nailhead

Royal Smart Person
Dec 1, 2014
1,564
113
Upstate NY
Depends on intended use. The 80 will
be strong enough for whatever you intend to do and will increase the resale value as well. I wouldn’t get wound up over the weight difference. Our cars are so heavy that another 100-150lbs is not a deal breaker.
 

Patobusta

Not-quite-so-new-guy
Thread starter
Jul 2, 2017
20
3
Car will be mostly cruiser and eventual stoplight to stoplight action. No slicks, no track in the foreseeable future.

What about gearing? I have a 8.5" 3.42 posi on it, 265/50/15 tires, will the 80e 1gear be too long?

I used hooker/holley swap kit so the crossmember is supposed to work, i believe driveshaft will do too.
 

OldsZZ383

n00b
Dec 29, 2019
2
1
Arizona
I just finished swaping an 2005 GTO lS2 4l65e driveline to my monte, and unfortunately the transmission is gone.. it just wont get into 3rd.
Now theres the decision, rebuilding the original 65e? or going 80e?

What are the pros and cons?

To me an 80e will always be stronger, and I believe it fits nicely, but some uneducated comentaries I heard about it been "heavier" meaning both mass and internal friction that might reduce the aparent power of the engine, and also the gearing of the 80e being "longer" than the 65e specially on 1-2, thus reducing the aparent excitement of the engine/car.

Do you guys agree? any experience with both of them?

Thanks!
I considered a 4L80E in my Cutlass but was told the transmission tunnel needed a lot of massaging with a sledgehammer... I am quite happy with the 700R4 behind my crate ZZ383. Definitely the 4L80E is a beefier transmission, but it is heavier... If you have more than 500 horsepower, go for it!
 

Hoopty_Mike

Greasemonkey
Aug 5, 2012
139
28
CT
I think you'll be stuck at a minimum getting a new driveshaft, the 4l80e is 2-3" longer than the 4l60/65. It also uses a heavier duty yolk that has a higher spline count so you'll need to source one of those. As for gear ratio It will be fine IMO, you have plenty of power. Sure you'll lose a little power but the 80e will be a way tougher trans, it's an electronic th400 with overdrive.

My first ls swap was a 4l60e and the 65s are only arguably stronger. I wouldn't waste a dime on another, they just never held up to the abuse and even in the tow rig got the dreaded no 2-3 shift.
 

Hoopty_Mike

Greasemonkey
Aug 5, 2012
139
28
CT
I considered a 4L80E in my Cutlass but was told the transmission tunnel needed a lot of massaging with a sledgehammer... I am quite happy with the 700R4 behind my crate ZZ383. Definitely the 4L80E is a beefier transmission, but it is heavier... If you have more than 500 horsepower, go for it!
cut the "ears" off the side of the 4l80e and flattening the flange in the tunnel is all you need for a 4l80e in these cars thankfully.
 

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
5,945
113
Spring, Texas
Have you done a cam swap in the LS2?

This is not apples to apples but annecdotal. I have a 2008 GMC Sierra Regular Cab/Short Bed that I bought new. It's a 2wd with a 5.3 and it had a 4L65E or 4L70E (not certain). I've done some typical bolts-ons including long tube headers, a cam, went to 4.10 rear gears (keep in mind, my 275-55-20 tires are nearly 32" tall), etc.

It's my daily driver and I enjoy driving it in a spirited manner. I did the cam swap at 82k miles. At about 114k miles 3rd started to go. I limped/babied it to 121k miles and then pulled it and had a performance build on it done (sun shell, shift kit, stacked pack on the 3-4 with an extra clutch, Corvette servo, etc., etc.). To be fair, the guy that built it for me may not have been the right guy for a performance build. The 1-2 shift was a bit aggressive (I liked it - would chirp the tires but he probably had one too many spacers in the 1-2 accumulator) and he probably should have advised me to put in a Billet Input shaft/drum and a billet output shaft along with the rest of the performance goodies. The first build didn't last but maybe 10k miles and it was pulling the input shaft out of the drum (re-used original). He mostly made good on it and installed the $900 billet input shaft/drum I supplied. That build lasted maybe 35k miles and the output shaft shattered on a wide open throttle 1-2 upshift. This was with a 5.3 with a mild cam (219/228 110LSA 525/525 lift).

At that point I felt like I was wasting good money after bad and I bought a 4L85E out of an 09 GMC Express 3500 cut-away van. I had it rebuilt and put a shift kit and some other performance goodies in it. At the same time, thanks to the advice of a friend on here, I did a lot better job matching the stall speed of the torque converter to my setup. With the 65E I was running a re-stalled stock converter (Circle D 278mm) 3200 RPM stall. With the 85E I'm running a 3600-3700 rpm stall. At first it was a little bit to get used to but what a difference! The truck is "fast" (It's still a 5000 lb. truck) and fun. The 278mm converter was too tight for the setup and the truck was a bit doggy on the low end. Either way you go, you need to plan on spending the money on a good converter that is well matched to your setup or you will be disappointed.

I've driven the 85E hard for 15,000 miles now. I did a drain and refill on it at 5000k miles and I'm about to do another, now that it's 10k miles later. That 4L85E is a beast. It takes anything I throw at it. It's the best thing I ever did to the truck. They shouldn't be putting 4L60/65/70E's behind anything making more than about 300 ft. lbs. of torque in my view and should have never put those transmissions in trucks.

If you are going to keep the LS2 totally stock and you aren't going to beat on it, in my opinion, you can get by with rebuilding the 65E but I would put the typical upgrades in it for durability while you are in there. Anything more than that and I strongly recommend the 80/85E. You won't regret it.

When I put the 85E in my truck I was worried about the different gear spread (taller first and less overdrive ratio). I overcame the taller first gear with more stall speed and a looser converter (I went with a 258mm Circle D instead of the slightly tighter 265mm unit they initially suggested). The truck performs better now that it ever did, speaking from a seat of the pants perspective. I've never taken it to a track. The steeper overdrive gear (numerically lower) isn't really that noticeable. With 4.10's and 32" tires, I turn around 2700 RPM at 85 mph. That gets a little old on a long trip because of the loud exhaust on the truck but it's not really that many RPM for the speed. Some perspective, it turns a little under 2000 RPM at 60.

With your 3.42 and the 2.48 1st gear ratio of the 4L80E, that gives you a final drive ratio in 1st gear of 3.42x2.48=8.48. I usually like to be in the 9's but I don't think this is terrible, especially considering the relatively short tire height (25.43") you have. My truck has 4.10x2.48=10.16 but has 31.9" tires. I think you can take care of any 1st gear too steep concern with torque converter selection. I think the LS2 makes enough torque that it doesn't need such a steep 1st gear as the 4L60/65/70E's 3.06:1.

Your 25.43" tall tire with a 3.42 and the 0.75 overdrive of the 4L80E should translate to about 2000 RPM at 60 and about 2900 RPM at 85. If the exhaust isn't too loud and the rest of the drivetrain and wheels/hubs/tires are smooth, this won't bother you, even on long trips. Here are a few calculators I really like...

Tire height calculator....

RPM calculator - use the bottom section labeled "Transmission Final Gear Ratio Manual Entry" (torque converter locks)

I hope this helps.
 

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
5,945
113
Spring, Texas
I think you'll be stuck at a minimum getting a new driveshaft, the 4l80e is 2-3" longer than the 4l60/65
This wasn't my experience when I did the swap in my truck. The 65/70E out of my truck was essentially the same overall length as the 80E but the transmission mount location on the 80E was about 6" back relative to the 65/70E, so I had to modify my crossmember. All I did on my driveshaft
20190223_160929-2016x1134.jpg
was swap the slip yoke as you noted above and the stock driveshaft went back in. Keep in mind, my truck uses 1350 series U-Joints stock, so there was no need to upgrade the shaft. That may not be the case depending on what the OP currently has. Here's a pic from my build thread of the two transmissions side-by-side. The 65/70E is in the foreground with the broken output shaft sticking out of it....
 

Hoopty_Mike

Greasemonkey
Aug 5, 2012
139
28
CT
That would be awesome for the OP in that case. I was always under the assumption that all vortec/ls 60/65/70s were the same dimensions, but from what I see that isn't the case as gto guys have gone 80e by just getting the yolk swapped. Should be able to get a conversion joint without much issue to get the proper slip yolk on the current shaft.

You'll also need some wiring modifications to accommodate the extra speed sensor on the 80e and some wires in the main trans plug will need to be moved around along with a 4l80e tune/segment swap done in your computer, a competent tuner shouldn't have much issue with that part.
 
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oldsmobile joe

Royal Smart Person
Nov 12, 2015
1,418
113
mpls
Tunnel clearance will be tight but do able with the 4l80e. Cooler line placement is the issue. I have a 6.0 and 4l80e swap going on. Drivetrain is in with the hooker mounts and cross member. My cooler line clearance is ok. And will improve with new body mounts.
Imo, spending money on a 4l80e is the smart money way to go.
 

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