• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

97 4L80E dropping out of TC lock up

I'm close to my "out of season" next 10 month parking spot, ive got a car to get around. so im fairly mobil. just need to get someone to make me those hoses.

in the meantime i run my genset to run down the tank. no way im lifting 400 pounds of fuel out of there.
 
get you some fuel jugs or a clean barrel, if you can rig up an inline pump and a battery to empty the tank in to the barrel or fuel jugs that way. heck even some clean 5 gallon buckets with lids will work. when done, you can use that same inline pump to put the fuel back into the tank.

that hose looks like it has been spliced in the past with what looks like a union and crimp collars made for a torch hose! I could be wrong there.

Now the threaded connection on the fuel tank sending unit might be hard to find other than from a parts store that sells by application for your rig.

others might know what the connection thread is or is called so you can get a connector that has a barb so you can run all new hose and not need to go to the dealer for that part.

in a pinch, cut the hose back past the union where it's still "good" and further up where it's still "good". get you two unions and some hose clamps with a section of new fuel hose to patch it in. that will get you going till you can replace it all.
 
sounds like a plan, working on getting a pic from the engine side.

the generac genset is making a general racket, i gues thats where the name came from :), to burn off parts of the fuel, im heating this night with space heaters...

i ask my friend if they have som jugs.
 
these are up front...
i wish they had done it all hard line... s.cks

taking the dog house apart always is a real pain
 

Attachments

  • IMG_20250413_210629434~2.jpg
    IMG_20250413_210629434~2.jpg
    156.1 KB · Views: 3
  • IMG_20250413_210653532_HDR~2.jpg
    IMG_20250413_210653532_HDR~2.jpg
    132.2 KB · Views: 3
honestly that looks like the factory p30 installation...

being professionally extended by national with 1 yard hose pieces and lots of crimping...

this pic is behind the stock drive axle...
 

Attachments

  • IMG_20250413_212142616.jpg
    IMG_20250413_212142616.jpg
    216.4 KB · Views: 2
forward of drive axle the filter, and above the drive axle goin into the rubbish National extension
 

Attachments

  • IMG_20250413_212600994.jpg
    IMG_20250413_212600994.jpg
    191.1 KB · Views: 3
  • IMG_20250413_212630207.jpg
    IMG_20250413_212630207.jpg
    150 KB · Views: 3
  • IMG_20250413_212625619.jpg
    IMG_20250413_212625619.jpg
    131.5 KB · Views: 3
i think tomorrow ill get some screw on fittings for 3/8 and 5/16 line (probably inverted flare for fuel lines), check if the wrenches would fit, if so then take just the fitting and test mount them, if that workes out, i measure the length and get me two new hoses made.

then i just need to get the fuel out some way or the other....

while at it im probably going ahead and get me a new fuel pump and filters. cause this one is sounding funny since some time, but i didnt know how the border crossing would go with new spare parte in the car so i did return it to AutoZone right before the Canadian border.
 
what do you think about exchangeing these rubber into nylon?

i basically could go from steel to steel with nylon, couldn't I?
 

Attachments

  • IMG_20250413_212630207~2.jpg
    IMG_20250413_212630207~2.jpg
    155.7 KB · Views: 1
  • Screenshot_20250413-202015~2.png
    Screenshot_20250413-202015~2.png
    149.8 KB · Views: 1
Those steel screw together fuel fittings has O-Rings on the end of a small line size protrusion fits inside of the female side of the fittings.
Is what I, and others I am sure, has done in the past is to slice those steel crimps lengthwise and getting right next to the hex fitting with using a grinder and cut off wheel, then breaking away what remains after making slices on opposite sides to get that steel crimp sleeve relieved.
Pull the old hose off the fitting, shove new hose over them then use hose clamps to hold the hose onto the fittings.
Unless You can find those specialty fuel line fittings that has hose barbs everything You do will be home made.
A good time to eliminate that crimped splice connector too and run straight through with hose.
Also, if You want to run mostly steel pipe then this would be a good opportunity. Wherever there is long runs of hose, use fuel/brake line pipe with the double flare fittings on each end, use double flare to hose barb adapters and hose clamps to make the transition from the special fuel line fittings to the double flare pipe and run the fuel through that.
 
highly appreciated Marty, its already steel all the way to the drive axle, just what National added (for the extended frame) after the drive axle is all rubbish, as I've come to expect of all mods they did to the P30 chassis.

so i basically will go out try to finde some guy who can provide these fuel line fittings to nylon adapter.

basically whats sticking out of my car and my tank is this:
https://affordable-fuel-injection.com/product/fuel-line-adapter/

the screw side with the o-ring, not the other normal hose side of that link.

and i need to find some sort of fitting going on these and then somehow adapter that to nylon shark bite.

or i go ahead and take my old hose apart and put new hose and decent hose clamps on. ( the cheap and fast and probably as durable way, if i can get that ethanol resistant hose)

funny thing is, at home i have a VW t25 vanagon multivan syncro 2.1 MV engine with DJ pistons (higher compression, factory max was with DJ at 112 hp, but the MV (95hp) with DJ pistons has emissions like an MV (before the car got 30 and became a classic one, it safed a substantially amount of emission taxes) but almost power like an DJ at about 108hp), its got one of these swedish ethanol box controllers who adjust injector timing according to o2 signal and its running mostly on 100% ethanol (what requires about 20% longer opening times on the injectors to compensate for the lower energy density of ethanol), and its got the factory fuel pump, injectors and hoses from 88, 10 years older than my RV here, and I literally never had any problems.... its been a turn key car ever since i bought it 18 years ago.
 
There are short adapters/carbs that screw into each side of the factory lift pump.

They're usually available in the help section of any parts store. I ordrr them off Amazon.

We've been using empty 55 gallon motor oil drums to fill and collect diesel. I'm not at all worried about any residue oil in the drums. We got ours from the Township.
Maybe make a few calls or talk to some friends. It doesn't really matter what kind of oil was in it.

Around here, I see 55 gallon drums for sale in marketplace all the time
We use a 12 volt transfer pump to move the fuel. There's also hand pumps available. Our current transfer pump came from Tractor Supply. I installed a filter on it - I like a 2 micron filter at the discharge of the transfer pump.

I also see these transfer pumps on marketplace fairly often. Sometimes with a portable tank. Maybe pick something up, use it and resell it

I wanted to switch from the 500 gallon tank to the 300 gallon tank - the 300 gallon tank needs cleaned out or replaced. We just don't use enough fuel right now to get tax free stuff and road use both.

It drives me crazy to use road fuel around here, but new fuel doesn't store well so we end up running road use fuel in everything.

It's a pia to get 5 gallon cans filled. We really need to get our fuel storage tank situation resolved in the next 2 weeks

https://www.amazon.com/gp/aw/d/B001EIXQ6C?psc=1&ref=ppx_pop_mob_b_asin_title

 
As an Amazon Associate we earn from qualifying purchases.
@mannebk You have gotten very good advice of 1) get a scanner on it and see what the computer (ECM) is seeing and doing. 2) Turn it TF around and drive the 2 hours back to a KNOWN GOOD RECOMMENDED SHOP esp. with your bitching about BAD techs/shops out there. Better yet where is your final destination your tail is on fire to push this malfunctioning rig to? Maybe a shop recommendation there will work esp. for warranty if needed.

Go ahead and waste your time and money rebuilding the trans. The rebuild can last exactly 30 seconds slipping before it burns a clutch pack up from slipping if you don't catch the problem. New parts don't mean good parts so if you introduce a second problem it gets more fun.

One of two things you will see on the scanner: Gear Commanded and Gear Selected. Also input and output RPM. If the gear commanded and gear selected is neutral you know the shifter is out of adjustment or the electronic switch on the side of the transmission (if equipped) is shot. If it's Gear Selected OD and Gear Commanded N (or 3) likely it's slipping the TCC or 4th Gear and MPH is too high to drop into 3rd. You need to know if something is slipping or if it's an electronic wiring etc. problem. Major info is any codes indicating a wiring problem or slipping.

The Overrun clutch for manual 3rd is a weak point. Doesn't take much to burn it up. You are taking the grades too fast and/or too heavy if you burn the brakes up. Other braking techniques may need work. Weigh the rig and make sure you are not overloaded. This transmission and a low compression 454 are Dog S! useless for compression braking anyway. Don't count on it: I couldn't as the weak manual 3rd overrun clutch was one of the first things I would burn up in a 4L80E towing the grades around here. (Then drive the trans with that burnt clutch 50K miles till the TCC started slipping and rebuild time.)

@GenBiltstein kinda sugar coated it but his advice is accurate. Couple things a good shop can do is apply "updates" to the transmission like more lube oil to some places. Also if you have say a rare cracked case leaking oil pressure the trans shop can find it.

60K miles at full weight... Even Grandpa going to church on Sunday has to get it close to the speed limit. The transmission, engine, etc. shown by single digit MPG is working harder than an unloaded pickup or Suburban. It may be low miles but it's hard miles. I was only getting 50K out of this transmission between rebuilds. Mainly the weak TCC slipping brought it in. Last one I fixed by simply dropping a Yank performance triple disc converter in.

One last thing: work on the rig when the exhaust is cold or header wrap the pipe in the area you plan on working on. Wrap would keep radiated heat to the trans down at least.
 
Last edited:
@mannebk You have gotten very good advice of 1) get a scanner on it and see what the computer (ECM) is seeing and doing. 2) Turn it TF around and drive the 2 hours back to a KNOWN GOOD RECOMMENDED SHOP esp. with your bitching about BAD techs/shops out there. Better yet where is your final destination your tail is on fire to push this malfunctioning rig to? Maybe a shop recommendation there will work esp. for warranty if needed.

Go ahead and waste your time and money rebuilding the trans. The rebuild can last exactly 30 seconds slipping before it burns a clutch pack up from slipping if you don't catch the problem. New parts don't mean good parts so if you introduce a second problem it gets more fun.

One of two things you will see on the scanner: Gear Commanded and Gear Selected. Also input and output RPM. If the gear commanded and gear selected is neutral you know the shifter is out of adjustment or the electronic switch on the side of the transmission (if equipped) is shot. If it's Gear Selected OD and Gear Commanded N (or 3) likely it's slipping the TCC or 4th Gear and MPH is too high to drop into 3rd. You need to know if something is slipping or if it's an electronic wiring etc. problem. Major info is any codes indicating a wiring problem or slipping.

The Overrun clutch for manual 3rd is a weak point. Doesn't take much to burn it up. You are taking the grades too fast and/or too heavy if you burn the brakes up. Other braking techniques may need work. Weigh the rig and make sure you are not overloaded. This transmission and a low compression 454 are Dog S! useless for compression braking anyway. Don't count on it: I couldn't as the weak manual 3rd overrun clutch was one of the first things I would burn up in a 4L80E towing the grades around here. (Then drive the trans with that burnt clutch 50K miles till the TCC started slipping and rebuild time.)

@GenBiltstein kinda sugar coated it but his advice is accurate. Couple things a good shop can do is apply "updates" to the transmission like more lube oil to some places. Also if you have say a rare cracked case leaking oil pressure the trans shop can find it.

60K miles at full weight... Even Grandpa going to church on Sunday has to get it close to the speed limit. The transmission, engine, etc. shown by single digit MPG is working harder than an unloaded pickup or Suburban. It may be low miles but it's hard miles. I was only getting 50K out of this transmission between rebuilds. Mainly the weak TCC slipping brought it in. Last one I fixed by simply dropping a Yank performance triple disc converter in.

One last thing: work on the rig when the exhaust is cold or header wrap the pipe in the area you plan on working on. Wrap would keep radiated heat to the trans down at least.
my tail is on fire

im flying out of here soon, be back in 10 months.

yep that's why I didn't go straight for a full rebuild

thank you so much for your insights

and I don't really have a home base here we're traveling so each out of season area is another place

this time it is Vancouver BC
 
not the sort of repair i was hoping for

but itll get me to my destination

national RV extended the factory lines, put some kind of crappy stuff in between, thats now crumbling....

the factory hoses are alright 30 years and ethanol and everything, just like my VW hoses with 28 years 100% ethanol...

so i replace that crappy piece of hose, and be done with it for this season, time to find a suitable way to go from o ring short pilot to nylon and back...

cause i want this fixed the right way and fuel pump and filter is on my bucket list since some time
 

Attachments

  • IMG_20250414_124510524_HDR.jpg
    IMG_20250414_124510524_HDR.jpg
    100.8 KB · Views: 5
  • IMG_20250414_120730383_HDR.jpg
    IMG_20250414_120730383_HDR.jpg
    86.6 KB · Views: 5
  • IMG_20250414_124537723.jpg
    IMG_20250414_124537723.jpg
    155.8 KB · Views: 5
  • IMG_20250414_124516265_HDR.jpg
    IMG_20250414_124516265_HDR.jpg
    129.4 KB · Views: 5
  • IMG_20250414_115412588_HDR.jpg
    IMG_20250414_115412588_HDR.jpg
    330.2 KB · Views: 5
Back
Top