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4l80e and the differences between years

dbrannon79

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iirc you would have to swap out the internal harness and the complete valve body from your old trans into the new one. plus retrofit the cooler lines. others will have to chime in but I'm not sure if the torque converters would also need to be swapped. though that alone is a big problem since if the old one is full of debris, it will destroy the new trans.
 

dbrannon79

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one other thought. check the tail section of the two and compare. you might have to swap them out also due to the speed sensors. I'm not sure if your old one has a cable driven gear or is electronic.

over all you might be better off by getting a kit and rebuilding your transmission or finding someone that would rebuild if for you. even getting a upgraded shift kit and clutches installed that would have a longer life if you can get a new torque converter or finding a good welder to open it up so you can get the internals cleaned. some places specialize in rebuilding the torque converters.

don't forget to clean and flush the lines and cooler too. and use only Dextron 3 fluid. not the newer Dextron 6 for your rig.
 

MrMarty51

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Ok, thanks for your answers, I think is better to buy a rebuild gearbox from the same year.

Thanks
That is a very wise decision.
You can too rebuild it Yourself, Get the book. It explains how to dismantle, clean, inspect, renew and reassemble.
It does take tools and preferably a clean, almost sterile, working station.
 

dbrannon79

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I've thought about trying to rebuild one my self. not sure if I could do it and it actually work LOL. most of the time when I take something apart and attempt to put it back together, there is always spare parts left over hahaha. but the videos I have watched make it seem simple if having the right tools.
 

MrMarty51

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I've thought about trying to rebuild one my self. not sure if I could do it and it actually work LOL. most of the time when I take something apart and attempt to put it back together, there is always spare parts left over hahaha. but the videos I have watched make it seem simple if having the right tools.
Lay it out, left to right, do not lay one ball, screw, bolt, nut, clip or pin to the side.
Test each clutch as they go together, before installing them, simply with an air blow nozzle. Keep it all clean and simple and it will work.
 

MrMarty51

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I have rebuilt several transmissions. TH350s, C6 Fords, 727 Chryslers, a Power Glide and even a 700R4.
One transmission failed right off. Pulled it back out, one sealing ring I had left off of a piston.
Installed that and put it all back together, took off and worked just fine, for near 100,000 miles before the state auctioned off that van.
 

dbrannon79

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BTW, what is the average life span of the 95 era 4l80e's with mine creeping up to the 300k mark knowing the engine is there. I really don't know about the tranny. it's working fine, but I would be inclined for a project to snag up on a rebuildable core one day and try my hand at it for a spare!

that is once I can clear out all the other projects I have now!
 

Husker6.5

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@dbrannon79 about 250K miles +/- 30K out the factory door. A lot depends on what the tranny has been subjected to use/abuse-wise, how it was maintained for fluid/filter changes and whether or not the torque converter lock up clutch and/or the overrun clutch have been abused and are shedding lining material throughout the transmission's internals.
 

dbrannon79

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Well I suppose a fella just loves to ride on the edge lol. if mine has not been into before, then shes doing real good for her age!! I was told way back when that my dodge tranny would fail at or around 100k and it's got 175k or so on her. Although she wont shift out of second unless you take your foot off the go pedal for a second, but shes been that way for years. a trans shop had once told me she wouldn't last much longer. in doing some research I found that it's simply a governor pressure sensor issue. since she was service at around 160k and don't drive here very much, I figure I would wait till she starts getting worse or change that next time a service is due.

I try my best to keep them serviced and have never put ether truck under a heavy load. they both have just been "goin to town rigs" since I have owned them. that has probably saved and prolonged their lives :)
 

AlaskaBill

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While it allows engine braking in 3-2-1, which the core TH400 clutches/steels are capable of handling, that kit still does not address the 4L80E's basic shortcommings, that being you can not engine brake in OD, with or without a heavy load/towing, without eventually tearing/burning out the OD section as the design just does not allow for enough steels and frictions to handle the load, nor does the OEM-design torque converter, either, with its wimpy lock-up clutch and easily warped housing that can only be adequately addressed by going with a billet converter and a double or triple disc, high friction clutches.

If you notice in Sonnax's own literature, it states that this kit prevents warranty claims and comebacks - that is it will (hopefully) let the tranny last beyond the warranty period offered by that shop, be it a 1/12K, 2/24K or 3/36K warranty or whatever.

There really is no permanent "fix" for the weak TCC or wimpy OD clutch design that prevents being able to engine brake (using some sort of exhaust braking device) with a 6.5TD/4L80E combo in OD, as you can with an Allison or the Aisin or newer Ford transmissions behind those diesels, only the way Sonnax devised to delay the inevitable mechanical failure of the TCC and/or OD clutch section to save shops having to eat the labor/parts to repair and replace either during their warranty period. Believe me, if there was an actual, permanent "fix" to the crappy TCC/OD issue that would allow engine braking in OD with the TCC locked - it would have already been invented and somebody very, very wealthy from it 20 years ago.

The problem with the 4L80E from the start is that it was a stop-gap, light-duty transmission - behind a light-duty diesel engine - that was modified with an add-on OD section and a locking TC for one purpose only - to get the maximum fuel mileage possible out of GM's pickup truck line, not to be used in the unforseen ways that the engineers never envisioned and that have been attempted since its introduction. Those people who intended the 6.5 for Medium Duty-type use went with a manual transmission behind it for good reason - the same reason why the military had the TH400, not the 4L80, in the HMMMV - because of its issues.
One way to get engine/trans braking in a pseudo-O.D. would be to use the Gear Vendor O.D. in 3rd. gear. That would likely be about half way between 3rd. and regular O.D. since the Gear Vendor is a gear splitter. If you ran larger circumferance tires that would also get you closer to stock O.D. You could always change your rear gear like I did to get acceptable highway speed at acceptable R.P.M's and stay in 3rd. with heavy lock-up in the tune for heavy towing.
 

Husker6.5

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One way to get engine/trans braking in a pseudo-O.D. would be to use the Gear Vendor O.D. in 3rd. gear. That would likely be about half way between 3rd. and regular O.D. since the Gear Vendor is a gear splitter. If you ran larger circumferance tires that would also get you closer to stock O.D. You could always change your rear gear like I did to get acceptable highway speed at acceptable R.P.M's and stay in 3rd. with heavy lock-up in the tune for heavy towing.
And that's a helluva lot of money to spend JUST to get pseudo-engine braking in "OD" out of a transmission that was NOT designed to engine brake in OD with - and then there's the cost of the exhaust brake needed to actually engine brake with a diesel on top of the rest of that cost. You might as well buy a used D-Max or Dodge that was designed with an engine braking capable transmission and an exhaust brake function in the turbo or added on aftermarket.
 

AlaskaBill

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Thank you for your help but would you happen to know how I would need to adapt them? I thought of that but the idea of just cutting the lines down to length, placing a rubber hose and some clamps on each one of them just doesn't seem logical as I'm sure 1 is under pressure, if not both.
You can buy transmission adapters to AN- 5 or 6. I upgraded my 5/16" to 3/8" (AN-6) and flared 3/8" stainless steel tubing. I got rid of the radiator and aux-transmission coolers and upgraded to a Derale 40 row fan cooled trans-cooler. Transmission cooling was my weakest Link untill I made the upgrade, now very cool, never an issue even towing heavy in the mountains.

You could just use AN-5 adapters and 5/16" tubing if you want to keep factory coolers.
 

AlaskaBill

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And that's a helluva lot of money to spend JUST to get pseudo-engine braking in "OD" out of a transmission that was NOT designed to engine brake in OD with - and then there's the cost of the exhaust brake needed to actually engine brake with a diesel on top of the rest of that cost. You might as well buy a used D-Max or Dodge that was designed with an engine braking capable transmission and an exhaust brake function in the turbo or added on aftermarket.
Well, yes it would be expensive. I'm not really interested in engine braking. Just commenting about trans kit that would give you 1-3 Torque Converter deceleration assistance. If you wanted OD decel (braking) you could get it with a Gear Vender splitter transmission.

I have been thinking about getting one because towing heavy on steep grades is difficult due to tall gears. 3 to 2 down shift is awful and instead, when you need power the most you have to take your foot off the throttle when it down shifts or boost and rpm go too high for my comfort. With a gear splitter, evidently one can maintain power with a milder down shift. Just $3500 😁
 
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