1987 345 w\454

[Keyair]

Personally, I have a 4L80e to hand. I picked it up for $200 locally. It looked good and clean inside, but am assuming it’s a core that I will either go thru it myself or use it as an exchange for a probuilt unit. Couple of Things I learned in my research. There are early 4L80’s and later ones. The earlier ones are easily identified by the positioning of the cooler lines. Earlier transmissions have these grouped together further forward, and later transmissions they are further back and separated somewhat. I read somewhere that the moved them to improve oil feed, and that might be important.
I am also seeing a decline in the cost of aftermarket stand alone controllers. They were in the $800+ range, and now I’m seeing some for half that. I think it important to note, that Mel had issues with one supplier on service. Remember, this unit needs a controller to work, and so reliability and service is critical. Me, I am looking at using a stock GM controller. These were an integrated Engine/Transmission controller. I found articles about people using this unit on a carburetor engine by replicating the feeds that the TCM needed. I also like the idea that there were millions of these ECMs produced and there should be good long term availability and support.

[Kreimer]

Just heard back from the mechanic and it is a cracked flex plate. Also told them to fix the starting issue I keep having. They seem to think that a factory starter will fix it. I told him if it still has the hot start issue I will bring it back to them and they can “fix” it again. For free...

[Waipio Rim]

I chased a hot start issue through a couple of starters recently. The culprit turned out to be a relay in the circuit, on mine it is located in front and to the left of the air cleaner. Can’t find it in any of the manuals, a mechanic found and fixed it for me.

[bobmiller1]

Cracked flex plate ? Did you end up towing it ! I still like the idea of the 4L85.....flex plate is a lot less expensive though....Regards, Bob

[bkahler]

Originally Posted by Waipio Rim

I chased a hot start issue through a couple of starters recently. The culprit turned out to be a relay in the circuit, on mine it is located in front and to the left of the air cleaner. Can’t find it in any of the manuals, a mechanic found and fixed it for me.

I think the hot start relay is documented in one of the P30 Chassis manuals. My 84 310 had the hot start relay but Peanut which is a 77 does not.

The relay is typically mounted to the same support bracket the oil filler tube and dip stick tube are clamped to.

Brad

[Kreimer]

Grrr. So I went and picked up the motorhome. Mechanic replaced the flex plate, starter, and added some missing nuts to the exhaust system. On the way home when I get to a stop I push on the gas and there is no power. I manually put the transmission in 1 and it moves. Acts like it isn’t shifting down all the way. There is a slight high pitched whine coming from the transmission. Also the exhaust is leaking worse now but that is easy enough. I checked the transmission fluid when I got it home and it is over full quite a bit. Obviously I need to get it down to normal operating levels but could that cause the weird behavior and noise from the tranny?

[bobmiller1]

Do you do any mechanical work yourself ??? Check the vacuum hose going to the modulator....May have come off when the transmission was pulled back to change the flywheel. I would pull the pan off and check the filter, also check for excessive debris in the pan. Did your guy add any fluid ??? I really hate paying anybody to do anything for me.....if you lived closer I would have you come over. We could try the face time thing on Sunday....I do it with Charly (Streamquest) often, Regards, Bob

[jdalrymple]

Don’t forget that you check the fluid level while the transmission is hot with the engine running and in park.

It will appear overfilled if engine is not running.


JD

[Paul J Mauro]

seems wierd that its only 88k on the odo??
My 85 345 has about 125,000 and we bought it new and had it ever since .
These rigs are great long distance road runners ,mine has been coast to coast many times.but as you will hear parts are pretty easy to get and a new motor is not that much either.good luck see you out there .

[Kreimer]

She’s had around 130k when the speedomoter quit last summer. She is back in the shop but no real news yet. Apparently they will be pulling the pan off Monday to see what they can see.....

[Kreimer]

New transmission is being built. Going back with the 475 for ease of install and $$$ considerations. This one is upgraded inside and has 10k towing capacity apparently. In other news they said my harmonic balancer is starting to dig into the oil pan. They are wanting almost 3k to change it. Is this something that I am crazy to think I can change myself? It looks like the hardest part will be the belts. i would like to do it without removing the front of the motorhome. Input and opinions would be awesome!

[Keyair]

I’ve done a balancer on a 454 before, but on my Suburban. Not super tricky. You need the removal/replacement tool tho.
If I remember correctly, all of the belts are on the pulley which is mounted on the front of the balancer with 3 bolts, and the balancer itself is mounted with one big center bolt to nose of the crankshaft. I cannot remember if the seal is pressed in from the front or rear of the timing cover. Replace it if you can.

[Magnet18]

Originally Posted by Kreimer

New transmission is being built. Going back with the 475 for ease of install and $$$ considerations. This one is upgraded inside and has 10k towing capacity apparently. In other news they said my harmonic balancer is starting to dig into the oil pan. They are wanting almost 3k to change it. Is this something that I am crazy to think I can change myself? It looks like the hardest part will be the belts. i would like to do it without removing the front of the motorhome. Input and opinions would be awesome!

What was the original towing capacity, and does that include the 15k motorhome on top of it? What are they upgrading?

I've seen our 475s referred to as the "dump truck transmission", and it's supposedly plenty beefy (if slow) if you don't let it overheat, which it doesn't sound like yours did.

Did they ever figure out root cause?

[Kreimer]

I have forgotten what the original towing capacity was but it couldn’t get any worse I am sure. i don’t remember the specifics of what is upgraded but he mentioned something about more plates and less heat... I know I should know all this but this is the part of the motorhome I am least familiar with. I do know they called it the road ripper but i need to ask them if it is the 2000 or the 3000.
https://www.certifiedtransmission.com/road-ripper/

I will know more when I go to pick it up hopefully. the unit is hopefully gonna be delivered to the shop tomorrow.

[Kreimer]

Got the transmission replaced and have not been able to take it on the highway because the harmonic balancer is shot. Instead of paying them 3k to replace it I decided to do it myself. So far I have gotten the balancer off. I am doing it from the bottom. I had to unbolt a cross member and alter the fan shroud to get to it but so far so good. Tomorrow I am gonna attempt to put the new one on. I replaced the seal while I had the balancer off. Man this old girl is a greasy mess underneath!

[Paul J Mauro]

just flew to orlando to pick up our 345 and take it back to Mass after 2 years in Fla. naturally I forgot to check all the air pressures and blew an underinflated rear inside tire. getting tough to find those original tires .goodyear had 2 I put on the front in Georgia.otherwise a good trip up and now set for New England trips again. Adult Toy Storage in Orlando were good people if you need them.

[Kreimer]

Dread blowing a tire on the highway... glad you were able to get it home and all is ok.

[Magnet18]

I steer clear of goodyears, especially for an RV

https://www.usatoday.com/story/money...ims/488815002/

https://jalopnik.com/goodyear-knew-o...-20-1824997252

[Kreimer]

Currently I am running Michelin’s on the front and Sampson’s on the rest. I don’t recommend Sampson’s.... in other news I got finished replacing the balancer and it is all back together! First time doing that. Ugh. But she again purrs like a pissed off cat in a bathtub!!! Fingers crossed!!!

[Keyair]

Good job!