94 slow

How strong is the stock 4l80E? What are some opinions of where(hp wise) it will fail? From what I have found/read, I think the trans will fail around 500-600hp.

Thanks for your two cents.

Also, I did a search...

Yank

iTrader: (181)

the GM rating is 885 ft. lbs input torque on the 4l80-e as to the GM rating of 670 ft. lbs. for the 4l60-e and 664 ft. lbs for the new 6l80

ChocoTaco369

i had to resurrect this. something is wrong here how can the 4L60E be rated higher in gearbox torque than the 6L80E...

Yank

iTrader: (181)

The #s are correct the 4l80-e is still the best transmission and has the highest rating

2007 Hydra-Matic 4L80/4L85 Transmission (MT1/MN8) 41806
Type: four speed rear-wheel-drive, electronically controlled, automatic overdrive transmission with torque converter clutch
Engine range: 4.8L - 6.0L gasoline
6.5L - 6.6L diesel
Maximum engine torque: 440 lb-ft (597 Nm) (MT1)
460 lb-ft (624 Nm) (MN8)
Maximum gearbox torque: 885 lb-ft (1200 Nm)


2007 Hydra-Matic 6L80 Transmission ( MYC ) 52206
Type: six speed RWD / AWD, electronically controlled automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture, with integral Electro / Hydraulic Controls Module
Maximum engine power: 469 bhp ( 349 kW )
Maximum engine torque: 439 lb-ft ( 595 Nm )
Maximum gearbox torque: 664 lb-ft ( 900 Nm )

jay_lt4

iTrader: (4)

strange,, i wouldnt put too much trust into those ratings, as at the dealer we see the 4l80e's blow up and that is with a stock gm engine

im not saying they are not a stong trans but they must be built correctly for the application, just dont think you can take a stock trans just because it is a 4l80e and put it behind some real power and have it last forever

WE TODD DID

iTrader: (2)

If you're going to use a 4l80, stay with an early model. The late models are junk. You can identify the early models by the cooler line fittings in the case being next to each other, as opposed to being spread apart on the late models.

ChocoTaco369

i'm aware the 4L80E is likely MUCH stronger than the 6L80E. the 4L80E is proven, the 6L80E isn't. in your original post, you put the 4L60E had a higher gearbox torque rating than the 6L80E. that's why i'm confused. is that spec that you posted about the 4L60E rated higher with gearbox torque than the 6L80E right?

98_Formula

iTrader: (15)

interesting... the 6l80e isnt really even an option for the fbody crowd ne ways is it?

ChocoTaco369

not yet. i believe the biggest problem is that the electronic controls are INSIDE the transmission, making it very hard to fit to an f-body. i'm sure it's possible as nearly anything is possible with enough money, but chances are, it'll be extremely expensive if it's ever done. also, while i have high hopes for the 6L80E, i have a feeling it won't be able to hold the power of a 4L80E fully built. i'll tell you what, it would be SWEET to have that in our cars with 4.10's. you probably wouldn't even need a converter

DeltaT

iTrader: (5)

In my experience GM way underrates their trannies. I have never seen numbers more than about HALF what you state above. I remember when the 4L65E was announced and they rated it at like 50ft/lbs higher than the regular 4L60E, like around 375 as opposed to 325.

I have the 4L80E and last time I saw the GM rating, it was like 480ft/lb.

That being said I recognize that you are a lot more tied into any tranny info than I am, but I did do a lot of research before I went for the 80E, and that's what I found. Like on the www.paceparts.com website, the GM tranny ratings there are more like what I remember.

Jim

back4more

actually the later model trannies are better, the converters are the worse part. Gm when they switched lighted the tcc piston in the converter.(in order to lighten it they made it thinner,weaker and more prone to cracking casuing the 1870) but if you buy an after market converter, which on this forum is not hard to find. The later are better units. i think the 6l80e is a lil undre rated at that, i mean its nothing more than a baby allison. the gearset is a compound set, and its clutch to clutch (for those who dont know what the hell that means it has no sprags. All allisons/ allison designs dont use sprags even the old at and mt series.

Yank

iTrader: (181)

Her is the GM website complete info on the 4l80-e
http://media.gm.com/us/powertrain/en...0(MT1,MN8).xls

joecar

The TCM being inside the trans. just means you have to pull the pan off to swap the TCM if you fry it while writing to it.

It shouldn't be too hard for a good fabricator to modify F-body sheet metal to accommodate the huge sized 6L80E.

It may be a little expensive, an extension housing has to be modified/made, but it won't be extremely expensive; I believe that somewhere/someplace someone may have already adapted one to an F-body...

I still think you need a converter since this "extends" the range in all gears by multiplying torque as needed (especially good on launch, even with an extra low 1st gear) and allowing the engine to remain in it's torque band in spite of the wide spaced gear ratios.

I think the 6L80E specs. are underrated at the moment... this is to be the transmission to replace all GM transmissions (just look at the size of it, and it is clutch-to-clutch spragless and has other "lessons learnt" durability features).

Edit: added to my post.

ChocoTaco369

i hope you're right, joe. i have very high hopes for this tranny. the fact that they haven't put it in the C6ZO6 scares me because that to me is GM telling us "we don't have an automatic that can handle 500 horsepower, even in such a lightweight car". but this is the first generation of 6L80's. i remember the 4L80 had weak points years ago but it's a much more capable trans from the factory now. i'm afraid that the 6L80 is going to be one tough transmission to build up, though. with 6 gears and a more complex design, i doubt it's as easy or cheap to work on as a TH400 or 4L80 but time will tell.

i also want to see torque management become a thing of the past. all hail the harsh factory shift

DeltaT

iTrader: (5)

You are quoting maximum gearbox torque and I was referring to maximum input torque.

Isn't max gearbox torque an internal transmission rating of the input torque allowable after the converter and any gearing reductions, like 1st gear? I didn't think it meant that GM is saying you could strap a motor putting out 882ft/lb of torque to a stock 4L80E, right?

Just trying to understand.

Jim

WE TODD DID

iTrader: (2)

I completely disagree. They totally re-designed the lube circuit in the late models, which in my opinion, is a weak link in them.

Yank

iTrader: (181)

Max gear box torque is after the converter STR ratio as the New models of transmission like the 6l80 have a very low STr rating converter like 1.55 theto allow for a larger torque input the 4l80-e was rated for a high STR converter more like 2.0 STR so it was built to handle that

If you put a 1.55 STR converter in the 4l80-e instead of the 2.0 the input torque rating would rise to 570 ft. lbs.

And the a 2.0 STR converter in the 6l80 would only allow a input torque of 332 ft. lbs. that is why the 6l80 have not held up with a converter change with TM removed

back4more

please explain because an early model 80e has cooler return oil in the front of the case sends it back to the rear section of the valvebody through a tube then through the center support and on the rear planet. late models have the cooler return straight into the rear into the center support and onto the gearset. gm did this becuase the lube oil doesnt heat up as much when it finally gets to the gearset, and when the trans is hot unflat mating surfaces, ie vb to case, is not a factor. so how is the early model a better deal?

WE TODD DID

iTrader: (2)

There was never an issue with lube in the early models, not to mention that the late models have a junky od sprag that will not withstand any sort of punishment! Plus, the early models have a better parts interchange and availability, being that some 400 stuff can be used.

Z'mnypit

iTrader: (58)

Thats funny, thats the 1st time ever Ive heard the early models being the stronger of the two. Everyone builder/shop ive ever talked with said go with the late model trans. I went with the late model version with the cooler lines spread apart, and ive beat the hell out of this trans trying to break it. Its defiantly a stout bitch. Plus I dont even think the early models will fit in the Fbody without some more fabrication. Im going to have to agree with back4more on this one, mainly because I have personal experence with the later models.