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Last Post 04 Aug 2008 11:12 AM by  Jim G
Chevy G3500 Express w/6ltr and 4L80E
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atcovan
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02 Jul 2008 03:42 PM
    Didn't want to jack another thread, but really want Steve Hoelscher's opinion about my trans, as he's seen several 4L60's blown. This is a 1-ton chassis, 2005 14-passenger van with 6 litre gas, a 4L80E and 50k miles on the clock that I thought about using for towing a racer, say... a 3500lb car in a 20' enclosed total about 5500lbs, or so. a Should I put a monster cooler on, Amsoil? What other advice can you share?
    pknowles
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    03 Jul 2008 07:05 AM

    The 4L80E is entirely different from the 4L60E and the 4L80E has far less trouble. My tow vehicle has 197k miles on it with the original 4L80E and I know a few people that have 8.1L's and are pushing 300k with the original 4L80E.

    Since the van is at 50K I would change the fluid and flush the trans. I flush my truck every 50k miles using an attachment that goes in place of the filter and uses the trans own pump to push out the old fluid and replace with new. I don't like the high pressure back flush machines. I also tow about 5500lbs, but with an open trailer.

    BigEnos
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    03 Jul 2008 11:13 AM
    A 4L80E is a great trans. no worries. 68K miles on my truck with a 6.0L 4L80E and no issues. Honesly I've never heard of one breaking, which is not to say that they don't, but it's not common.
    atcovan
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    03 Jul 2008 11:50 AM
    Thanks for the comments, guys. I figured this forum would be a wealth of knowledge and experience. I did change the fluid/filter and drove about 100 miles, then did it again. The first flush wasn't really dark at all, but now, the fluid is so clean, it's difficult to see the level on the stick! I installed a B/M aluminum pan which added three quarts more and has a drain. ATF is cheap enough, so does changing at 25K intervals seem prudent? I should add, this van is used almost daily as a taxi for up to 14 people and their luggage in a 5x8 trailer. I can't seem to find an external cooler, so should I add that, as well and maybe a temp gauge? I live in the Sacramento area, so winters are mild, as far as over-cooling goes.
    pknowles
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    03 Jul 2008 12:24 PM
    Unless you tow with it constantly changing the fluid every 50k should be enough. Mine sees 25% towing and 75% other by mileage and even after 50k my fluid still looks great, but I change it because that is the recommended interval. Look again for the cooler, there has to be one on a 1 ton van.
    BigEnos
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    03 Jul 2008 12:33 PM

    pknowles wrote:
    Unless you tow with it constantly changing the fluid every 50k should be enough. Mine sees 25% towing and 75% other by mileage and even after 50k my fluid still looks great, but I change it because that is the recommended interval. Look again for the cooler, there has to be one on a 1 ton van.

    It may be integrated in the radiator to save space, I'm no expert on vans but that's not uncommon. My 2500HD has a big external cooler IIRC. Look in the engine bay for trans fluid lines running to and from the radiator area (they are smaller than the water hoses).

    atcovan
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    03 Jul 2008 04:31 PM
    BigEnos wrote:

    pknowles wrote:
    Unless you tow with it constantly changing the fluid every 50k should be enough. Mine sees 25% towing and 75% other by mileage and even after 50k my fluid still looks great, but I change it because that is the recommended interval. Look again for the cooler, there has to be one on a 1 ton van.

    It may be integrated in the radiator to save space, I'm no expert on vans but that's not uncommon. My 2500HD has a big external cooler IIRC. Look in the engine bay for trans fluid lines running to and from the radiator area (they are smaller than the water hoses).

    You were right, Brian. Both the trans and engine oil coolers are integrated into the radiator tanks. I'm going to install a trans temp gauge to see if I need an external cooler. It gets hot in the summer, so I don't need problems, especially when I have a full van of travelers who need to get to the airport. It's one thing to be stuck while hauling my buddies racer, quite another if I breakdown with customers. Thanks.

    Jim G
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    03 Jul 2008 10:44 PM

    I'm pretty ignorant on this topic. How do you find out what transmission is in a vehicle? I've got an '06 1500 Savana with 5.3 liter engine. None of my documentation mentions transmission code. Not that I'm going to go out and sell the van, but it would be useful to know.

    Any help is very much appreciated.

    pknowles
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    04 Jul 2008 09:43 AM
    You have to find your factory RPO sticker, mine is in the glove box. The "M" codes are for the transmission. A quick search of the internet should reveal what your codes mean, but unless they have changed M30 is the 4L60E and MT1 is the 4L80E. In a 1/2 ton with a 5.3L you probably have the 4L60E.
    Steve Hoelscher
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    04 Jul 2008 12:44 PM

    atcovan wrote:
    Didn't want to jack another thread, but really want Steve Hoelscher's opinion about my trans, as he's seen several 4L60's blown. This is a 1-ton chassis, 2005 14-passenger van with 6 litre gas, a 4L80E and 50k miles on the clock that I thought about using for towing a racer, say... a 3500lb car in a 20' enclosed total about 5500lbs, or so. a Should I put a monster cooler on, Amsoil? What other advice can you share?

    Hi Jim, Sorry I am late to the party. I was in Daytona for the Grand Am race. [Y]

    The 4L60E and 4L80E are not related. As already noted, the 4L80E is a much better transmission. It has been Chevy's heavy duty automatic since the early to mid '90. They are used in 3/4 to 1 ton, trucks vans and suburbans. Also, the big Caddy SUVs.

    While it is a better transmission than the 4L60E (figuring too that it is intended as a higher capacity transmission) it is not without its own issues. The transmission's reputation is to work well for a long period of time and then to fail catastrophically. They can be expensive to overhaul. 100,000+ miles in heavy service (hauling and towing) is typical. My shop did the transmission work for both CSX and Norfolk-Southern rail roads. Their trucks are alway badly overloaded (because of the rail wheels) and by company policy, cannot be shut off while on the rails. They also run three shifts a day in most cases.

    We had good service from the units we built. I should also note that like the late model 4L60Es, the 4L80E has a torque coverter lockup strategy that regulates torque converter clutch slippage constantly. It almost never fully locks, there is always some amount of slip, in the range of 5 rpm to about 30 rpm of slip. More than 50 rpm for more than 10 seconds will cause a torque converter slip code and put the tranmission in fail safe mode.

    Because of this lockup strategy, these transmission generate a LOT of heat when towing. Therefore a big aux cooler is a VERY good idea. I wouldn't consider towing without one. Yes, there is cooler integrated into the end of the radiator but that is inadequate. More is ALWAYS better when it comes to coolers on automatics. Install the largest Hayden (or plate type cooler) in middle of the grill for max airflow.

    Also, for any vehicle that sees regular towing duty, 20K to 25K miles is the recommended fluid service interval. Especially on these transmission (due to the torque converter's lockup strategy). Use a qualty, name brand, fluid. Castrol, Texaco, Exxon, etc... Stay away from the store brands (Advance Autoparts, Autozone, etc..) as these are very low grade fluids and don't live well in high temp applications.

    A final note on transmission fluid; Changing your fluid when it gets dark is too late. Transmission fluid is basically hydraulic fluid that has a complex additive package that contains stabilizers and cushioning agents. You change the fluid because the additives break down from heat and mileage, not because the fluid gets dirty. Dark fluid results from one of two causes: 1) varnish: the result of the fluid breaking down from age and heat. 2) contamination: the results of burnt clutch material and/or metal from transmission wear. Transmission fluid should be changed BEFORE it gets dark. If you tow regularly and use the vehicle as a daily driver, I would recommend changing the fluid annually.

    The two best things you can do for your automatic is to use a quality cooler and change the fluid regularly using a quality fluid.

    atcovan
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    06 Jul 2008 04:12 PM

    Thanks very much, Steve, as well as all the other folks who took time to share. I think I'm fortunate that the drain oil wasn't murky-dark, just a little different from new. It was an Enterprise rental passenger van, so I doubt anyone changed the fluid, but at 50k, there wasn't "mud" in the bottom of the pan, or metal shavings on the magnet when I changed it for the bigger, aluminum pan. A BIG cooler and good fluid is going in this weekend!

    PS So, el-cheap-o, $8 / gallon Walmart Super-Tech fluid is not okay? Dang, I was hoping to save some $$ [:)]

    PPS Should a cooler be placed with the inlet/outlets in the up, down or sideways position. I always thought sideways for plate-type would allow a more complete drain, but I've also seen instructions with the connections facing up, so it's always full. Is there a problem with trapping air, or what?

    PPPS Should a cooler be installed before, or after the in-radiator, factory part. My guess is before, so the fluid does get warmed-up when it's cold outside, right?

    slowSER
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    07 Jul 2008 09:05 AM
    Jim G wrote:

    I'm pretty ignorant on this topic. How do you find out what transmission is in a vehicle? I've got an '06 1500 Savana with 5.3 liter engine. None of my documentation mentions transmission code. Not that I'm going to go out and sell the van, but it would be useful to know.

    Any help is very much appreciated.

    A trick I learned a few years ago selling rebuilt transmissions, a quick visual ID from outside, if it's a 2500+ with 8-lug wheels, it's a 4L80E. I don't recall any of us coming across a 1/2 ton truck or van with a 4L80, although maybe there was some obscure work truck or HD 1/2 ton that got it. The 8-lug wheels were pretty much a dead giveaway, though.

    Or you can count the bolts on the pan. [:D]

    Pat

    pknowles
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    07 Jul 2008 09:43 AM
    The only 1/2 tons that I'm aware of that got the 4L80E where the 6.5L diesels.
    Steve Hoelscher
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    07 Jul 2008 10:14 AM
    atcovan wrote:

    Thanks very much, Steve, as well as all the other folks who took time to share. I think I'm fortunate that the drain oil wasn't murky-dark, just a little different from new. It was an Enterprise rental passenger van, so I doubt anyone changed the fluid, but at 50k, there wasn't "mud" in the bottom of the pan, or metal shavings on the magnet when I changed it for the bigger, aluminum pan. A BIG cooler and good fluid is going in this weekend!

    Mud is evidence of a big problem. Good practice for servicing the transmission is to change the fluid while its still in good condition. Still pale red and before it takes on a brown tint.

    atcovan wrote:

    PS So, el-cheap-o, $8 / gallon Walmart Super-Tech fluid is not okay? Dang, I was hoping to save some $$ [:)]

    If I remember correctly, WalMart sells Castrol brand fluid in gallon jugs.

    atcovan wrote:

    PPS Should a cooler be placed with the inlet/outlets in the up, down or sideways position. I always thought sideways for plate-type would allow a more complete drain, but I've also seen instructions with the connections facing up, so it's always full. Is there a problem with trapping air, or what?

    I would mount the cooler with the lines either sideways or down. Don't worry about the cooler daining or staying full. And no, it won't trap air.

    atcovan wrote:

    PPPS Should a cooler be installed before, or after the in-radiator, factory part. My guess is before, so the fluid does get warmed-up when it's cold outside, right?

    Always install the cooler after the radiator. That way it provides additional cooling instead of the radiator heating the fluid.

    As for 4L80E fitment criteria: I never saw a 4L80E in a half ton truck chassis. We had a Chevy 1500 pickup equipped with a diesel and a 4L60E. The truck was used as a coke machine delivery truck and was fitted with a tailgate lift. The transmission wouldn't last more than about 6-8 months.

    The easy way to ID the two transmissions is to look at the pan. If the pan is a pure rectangle, its a 4L60E. If the rear edge is rounded, its a 4L80E.

    BigEnos
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    07 Jul 2008 11:52 AM
    I just got back from the Toledo Pro. According to the dash gauge, the trans never went above ~190*, generally staying in the 160-ish range while running. The only time it crept up is while sitting still (in holiday traffic coming home) and during the subsequent crawl up the PA mountains in said traffic. 2003 Silverado 2500HD, btw.
    autoxgod
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    26 Jul 2008 12:21 AM

    I have a Hughes high capacity tranny pan for sale for the 4L80E. $100 and I'll bring it to Topeka for Nationals otherwise contact me if interested. I couldn't use it on my 3500 Express since the exhaust cuts across the rear of the pan.

    I'm looking at getting the pan that is made with the recessed portion to fit.

    Jim

    atcovan
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    29 Jul 2008 01:13 PM
    autoxgod wrote:

    I have a Hughes high capacity tranny pan for sale for the 4L80E. $100 and I'll bring it to Topeka for Nationals otherwise contact me if interested. I couldn't use it on my 3500 Express since the exhaust cuts across the rear of the pan.

    I'm looking at getting the pan that is made with the recessed portion to fit.

    Jim

    That's why I went with the B&M aluminum pan. Not only does it clear the exhaust, but it also adds 3 quarts capacity and has a drain plug. Interesting note... There's a transfer tube at the rear of the 4L80E which goes from the valve body to the case which makes installing this pan a real pain if you don't drop the exhaust pipe an inch, or so. I didn't have the proper tools to break (literally, if rusted) loose the nuts on the flange and working on my back in the driveway isn't conducive to good shoulder care. I stared at this a good while, wondering what to do about it. Then, I noticed the B&M pan has extra meat cast there and the gasket has a little curve right there. A few minutes with a rat-tail file gets the job done! Make sure you wrap the pipe with insulation, or you'll heat the fluid fairly well. So far, no leaks and it's supposedly stiffens the case, as well.

    Jim G
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    30 Jul 2008 12:37 PM

    To install a temp gauge for the tranny, where is a good place to put the sending unit?

    atcovan
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    30 Jul 2008 01:09 PM
    Jim G wrote:

    To install a temp gauge for the tranny, where is a good place to put the sending unit?

    Mine is in the pan. I believe it gives the most accurate reading.

    Steve Hoelscher
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    30 Jul 2008 03:04 PM
    Jim G wrote:

    To install a temp gauge for the tranny, where is a good place to put the sending unit?

    Most aftermarket trans temp gauges mount the senders in the line pressure tap. This is the best location.

    As an alternate, the output line to the transmission cooler is good.

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