New-to-me 97’ 4L80e 4x4 with 240k miles has reverse, no forward gears.

[Cleverbever]

Just picked up a service truck for a $1000 bucks… the seller said it’s been parked for about 2 years. Jump started it and reversed onto the trailer perfectly. But shifter wouldn’t go past D on the dash.
Got home and found the trans cable was loose… adjusted it, has a floor shifter for 4x4 so with it off went through 4lo, 2Hi 4hi, seemed alright.

Started truck, no forward gears in drive, or manual 321. Tried it in 4 hi, and had very sluggish movement forward, put it in neutral went to 4 lo, was able to creep around parking lot.

Put it back in drive + 4hi, got to 15 mph and switch to 2 hi, was able to go around the block slowly and did feel it make one shift. Parked it as I was out of time.

Next day checked fluid, tried the same thing and it wouldn’t do anything.

Any suggestions on where to start? Could that be electrical? Or should I just go ahead and pull the trans and brace my wallet for an overhaul?
I’m an equipment mechanic so I’m not afraid of a fun challenge. Or should I find a lower mileage junkyard trans to start overhauling/have more salvageable parts?

 

[NickTransmissions]

Just picked up a service truck for a $1000 bucks… the seller said it’s been parked for about 2 years. Jump started it and reversed onto the trailer perfectly. But shifter wouldn’t go past D on the dash.
Got home and found the trans cable was loose… adjusted it, has a floor shifter for 4x4 so with it off went through 4lo, 2Hi 4hi, seemed alright.

Started truck, no forward gears in drive, or manual 321. Tried it in 4 hi, and had very sluggish movement forward, put it in neutral went to 4 lo, was able to creep around parking lot.

Put it back in drive + 4hi, got to 15 mph and switch to 2 hi, was able to go around the block slowly and did feel it make one shift. Parked it as I was out of time.

Next day checked fluid, tried the same thing and it wouldn’t do anything.

Any suggestions on where to start? Could that be electrical? Or should I just go ahead and pull the trans and brace my wallet for an overhaul?
I’m an equipment mechanic so I’m not afraid of a fun challenge. Or should I find a lower mileage junkyard trans to start overhauling/have more salvageable parts?

Rule out the tcase and other external causes first then yank the trans for overhaul.

Check out my 4L80E Info thread for video instruction, parts lists and other resources to help you with your build. Let me know if you need any assistance with questions.

 

[Cleverbever]

Rule out the tcase and other external causes first then yank the trans for overhaul.

Check out my 4L80E Info thread for video instruction, parts lists and other resources to help you with your build. Let me know if you need any assistance with questions.

Thanks Nick! I’ve been binging all your YouTube videos trying to prep myself for the teardown. All your hard work is very appreciated!!

Going to the junkyards this weekend to see what’s around.
I initially got the truck for the bed but decided it’s perfect the way it is. Just needs a little love and maybe an LS swap down the road lol

 

[NickTransmissions]

Thanks Nick! I’ve been binging all your YouTube videos trying to prep myself for the teardown. All your hard work is very appreciated!!

Going to the junkyards this weekend to see what’s around.
I initially got the truck for the bed but decided it’s perfect the way it is. Just needs a little love and maybe an LS swap down the road lol

Awesome man, thank you!

Yep, an LS swap sounds like a great idea...4L80E will work nicely with it.

 

[Cleverbever]

@NickTransmissions what years am I looking for in junkyard 4L80e? 97-2002? Ideally I’d like to find the years that would work for the current 97 5.7 and then later with a 6.0 junkyard pull out.

 

[NickTransmissions]

@NickTransmissions what years am I looking for in junkyard 4L80e? 97-2002? Ideally I’d like to find the years that would work for the current 97 5.7 and then later with a 6.0 junkyard pull out.

99+ if you plan on doing your LS swap sooner rather than later as those cases all had the top bolt hole location on the bell. To be clear, this isnt important or mandatory as 97-98 are also fine and will work just as well. If you're going to the yard and find a truck or suv 4wd with its 6.0 and 4L80E still installed, grab them both.

 

[Cleverbever]

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@NickTransmissions how bad would you consider this? I don’t see any huge chunks. But fluid was black and smelled weird, like vinaigrette lol

 

[Cleverbever]

@NickTransmissions I’m going to check everything I can with the cover off from your videos. Thanks for making them!

 

[Cleverbever]

99+ if you plan on doing your LS swap sooner rather than later as those cases all had the top bolt hole location on the bell. To be clear, this isnt important or mandatory as 97-98 are also fine and will work just as well. If you're going to the yard and find a truck or suv 4wd with its 6.0 and 4L80E still installed, grab them both.

@NickTransmissions What’s the latest year 4L80e that will bolt to the 5.7? I found a 4x4 2006 scouting at the junkyard yesterday. Will the 12 o clock bolt hole matter on the 97 5.7? Also would I need anything else from 06 donor like flex plates or anything?

 

[NickTransmissions]

@NickTransmissions What’s the latest year 4L80e that will bolt to the 5.7? I found a 4x4 2006 scouting at the junkyard yesterday. Will the 12 o clock bolt hole matter on the 97 5.7? Also would I need anything else from 06 donor like flex plates or anything?

2006 unit is fine to swap to a 5.7 Gen 1 SBC...There were two different converter designs as it relates to the depth/height of the converter's hub (see my 4L80E Info Thread for specifics on this) and I believe that was owing to the differences in crankshaft mounting flanges for the flex plate so just purchase a converter with a body that correlates to the Gen 1 SBC 5.7L engines. As mentioned, the 12 o'clock bolt hole is irrelevant when it comes to mounting to any Chevrolet-pattern engine block. You should be able to reuse your flex plate on your engine.

If the trans does come with a converter, buy it as well; if nothing else it will allow you to turn in a core when you purchase a new converter....Lastly, don't buy any torque converters from chain auto parts stores..I've seen too many problems with them.

Grab the cooler lines off of the 2006 donor vehicle as well - flush them before installation, as well as your own radiator's trans cooler and any external coolers before installing the replacement transmission.

Dont forget to perform the tests described herein before you send any cash across the table...If you're able to pull the unit yourself, pop the pan off so you can see what's at the bottom...If it looks anything like that picture above, pass it by...

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Lastly, replace the filter, all solenoids, pressure switch manifold assembly and new wiring harness with a new Rostra Harness for 2004+ 4L80Es before installation.