Duramax with a 4L80E

cbarnett_2500

New member
Apr 23, 2015
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Hey there fellas.

I despise forums, but, seeing as how I couldn't find anything anywhere else, I figured I'd bite the bullet and ask here for help. I am looking at doing a full duramax drive train conversion into my 2000 Silverado 2500 non-HD. The engine is good, but the transmission is stuck in 3rd gear.

That being said, today, I ordered a brand new transmission to replace my broken stock 4l80E. It's a Monster heavy duty 4x4 Transmission with stage 2 firm gears, a 1800-2000 stall heavy duty convertor, lockup etc. It is supposed to handle up to 550 hp and 650ft lbs of torque with normal parts, but since it's being built up a bit, I expect it to handle more.

My question is simple. Will the Duramax engine bolt up to the 4L80E? If so, will my built 4L80E be able to withstand the Duramax engine? Keep in mind that the only thing I'll be doing is a high flow intake to the turbo and a turbo back exhaust. I might do some mild tunes later.

Thanks guys! I look forward to reading your comments!!

Cbarnett_2500:confused:
 

Mike L.

Got Sheep?
Staff member
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Aug 12, 2006
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The 4L80 will bolt up to the Duramax with proper converter. The weakness will be 4th gear. If the weight is light you stand a chance that it will hold.
 

clrussell

pro-procrastinator
Sep 23, 2013
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That still does not answer my question of why would 4th gear not hold?


Heavy ass truck and 4l80 with a dmax in front of it... The trans is "rated" at 550hp 650tq you say right? Which is a lot in the gas world.. Dmax not so much..

If mike says 4th won't hold it won't hold.

Other than that I don't know why.


Sent from my iPhone using Tapatalk
 

malibu795

misspeelleerr
Apr 28, 2007
7,841
280
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in the buckeye state
"Weak" first thing that failed on my dmax/4l85 was the sprag, then the TCC.
Spent a lot of time over 20,000lbs with alot of throttle at 275-300 hp..
There is a build thread for a 4l80 to hold power.. JoshH is the author iirc
 

Muff

Just Learning
Oct 7, 2013
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Butler, Pa
Where are you located? Who builds this monster 4l80e? Mike also said 4th gear wouldn't hold when I made a thread about putting one in my drag truck. Josh H has been running his 4l80e for years and using 4th in his drag racing van and it's still working good for him. That's not a shot at you mike please do not take it that way. The only way your really gonna know is have the transmission built properly for your application and give her hell. I think it'll work fine but I have 0 first hand expierence. Best bet is to call Josh at top notch garage and ask for his advice. I wanna install a 4l80e in my daily driver to see how it holds when built properly to towing abuse behind the duramax. Mainly because they are a much cheaper transmission and I'm and idiot. :roflmao:
 

JoshH

Daggum farm truck
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Feb 14, 2007
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Like Mike said, the OD roller clutch is a known weak link on the 4L80E/4L85E transmissions. If you have a heavy foot and run it hard in the D position, you will probably break it eventually. What I do to help prevent this from happening is launch with the shifter in 3 instead of D. This brings on the OD overrun clutch which helps the OD roller hold and takes some of the load off of it. I have no idea who you are getting your trans from, but I bought mine from "the best in the business" when it comes to building the 4L80 and had nothing but problems out of it. I would recommend talking to Rossler if you aren't capable of building it yourself.
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
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What year Duramax? You're going to need a custom harness/standalone setup to make the 4L80 work nicely with the Duramax.
 

cbarnett_2500

New member
Apr 23, 2015
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I'm gonna guess he is refferring to these guys. http://www.monstertransmission.com/ If so they do NOT have a very good reputation for building a good trans. Theres alot of threads out there on different forums regarding there work as being sub par to say the least.

I'd like to see some of these threads. I know many people who have ordered transmissions from them and all they have to say is good. Besides. If what everyone is saying is true, regarding the difficulty of keeping the transmission from blowing up with the duramax, then I'll just stay with my 364 Vortec, which, at most, puts out 350 HP and 367-70 ft lbs of torque.

Please keep in mind that the transmission is the heavy duty version that will only be moving my truck. Nothing else, other than MAYBE a fourwheeler at random times.
 

Mike L.

Got Sheep?
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Aug 12, 2006
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I'd like to see some of these threads. I know many people who have ordered transmissions from them and all they have to say is good. Besides. If what everyone is saying is true, regarding the difficulty of keeping the transmission from blowing up with the duramax, then I'll just stay with my 364 Vortec, which, at most, puts out 350 HP and 367-70 ft lbs of torque.

Please keep in mind that the transmission is the heavy duty version that will only be moving my truck. Nothing else, other than MAYBE a fourwheeler at random times.

You will probably be fine in your case. It's the massive tq under hot rodding along with the heavy weight that will do the 4L80 in.
 

SmokeShow

Well-known member
Nov 30, 2006
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Keep in mind, this board is performance driven for the most part, hence these guys are typically meaning the 4L80/85E won't last in a heavy vehicle if you aim to do any hotrodding around with it.

malibu795 gave testimony on the 4l80/85E that he had in his hotshot truck which seems to be more in line with what you're doing - not a performance oriented build??? IIRC, he ran tuning from a van which is less powerful than the stock tuning for the pickups and he still had the issues he mentioned. Granted, he was towing very heavy loads which you say you won't be doing.

Quite honestly, the "heavy duty" version you speak of won't be near enough to do more than easy cruising IMO. If you have a heavy foot you're likely going to end up with a failed 4L80/85E transmission. If you drive easy and just going to cruise in it, I'd be inclined to believe that a properly built 4L80/85 can handle that task.

If whoever you bought this built transmission from has never built one to go behind a duramax or other diesel engine, their credibility from the gas world goes out the window IMO. They just don't know that their stuff is going to handle the gobs of torque at low RPM as compared to a gas-powered vehicle.


May I ask why you seem to be defensive about the advice you've been given here so far? What exactly are you looking to get out of this discussion because it doesn't seem like you're taking the advice/suggestions that have been offered too well. :confused:
 

lts1ow

Needs moar PAH!
May 14, 2012
1,598
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NJ
I'd like to see some of these threads. I know many people who have ordered transmissions from them and all they have to say is good. Besides. If what everyone is saying is true, regarding the difficulty of keeping the transmission from blowing up with the duramax, then I'll just stay with my 364 Vortec, which, at most, puts out 350 HP and 367-70 ft lbs of torque.

Please keep in mind that the transmission is the heavy duty version that will only be moving my truck. Nothing else, other than MAYBE a fourwheeler at random times.

Really...? The internet, use it.
http://monster-transmission.pissedconsumer.com/

That was literally 5 seconds of searching. I wouldn't touch their stuff with a ten foot pole.

My 80e is still alive, but I have it in a 3400lb chassis ;)
 

bmc1025

Member
Jan 25, 2013
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Big Bone, KY
You would be money and time ahead by buying the best hard parts and proper converter. Then learning on your own doing some research and trial and error. Vs going with monster and still having the headache they will charge you for.
 

cbarnett_2500

New member
Apr 23, 2015
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Really...? The internet, use it.
http://monster-transmission.pissedconsumer.com/

That was literally 5 seconds of searching. I wouldn't touch their stuff with a ten foot pole.

My 80e is still alive, but I have it in a 3400lb chassis ;)

Aight hotshot. Lose the attitude. If you actually took the time to read my OP, then you would realize that I already bought the transmission. Also, I'm not going to be hotshotting around. This is a daily driven truck, and I was able to get a really good deal on the tranny.

My stock 4L80E just went out after 204k miles, so I needed something new. Jasper transmissions were 400 bucks more, a rebuilt transmission in the stock casing was 600 bucks more. So I went with what I knew.


Also, Smokeshow, I'm not being defensive about the information at all. I came here to learn, as I said in the OP. If anything, I'm just trying to understand everything. I don't take stuff for face value. I ask for reasoning behind what people say. However, I already bought the transmission. So I'll just put it on my current engine and drive it till it breaks again. My guess is that the engine will go before anything else anyway.

Just as an FYI, one of my best buds bought one for his 2500HD with the gas engine. It's still running strong after over 100k miles.
 

cbarnett_2500

New member
Apr 23, 2015
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I made this thread to learn, but instead, all I got was a bunch of attitude and people telling me that I'm basically an idiot. There are reasons why I no longer use forums. I shouldn't have even asked y'all.
 

duramaxzak

Wanna be puller!
Nov 22, 2008
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I made this thread to learn, but instead, all I got was a bunch of attitude and people telling me that I'm basically an idiot. There are reasons why I no longer use forums. I shouldn't have even asked y'all.

So...you don't like forums because people don't tell you what you want to hear? :confused: