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1993 454 3500 HD dump truck 4l80e

Dumptruck454

Dumptruck454

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Location
Dover Kentucky
I have a 93 454 3500 HD dump truck freshly rebuilt transmission 4L80E my speedometer is 15 mph off when it shifts it doesn't matter if it's first or second to third or third or overdrive it shifts and then shifts back down going down the road it'll lose overdrive and will not shift back in any ideas
 
Is that 15mph off reading faster (ie: reads 45 when you're actually doing 30) or reading slower (ie: reads 30 when you're actually doing 45)? Was that a bought off the shelf rebuilt, or did you (or a shop) drop the one in it and rebuild it and reinstall it?
 
Husker6.5 said:
Is that 15mph off reading faster (ie: reads 45 when you're actually doing 30) or reading slower (ie: reads 30 when you're actually doing 45)? Was that a bought off the shelf rebuilt, or did you (or a shop) drop the one in it and rebuild it and reinstall it?
Click to expand...
It was rebuilt
 
Husker6.5 said:
Is that 15mph off reading faster (ie: reads 45 when you're actually doing 30) or reading slower (ie: reads 30 when you're actually doing 45)? Was that a bought off the shelf rebuilt, or did you (or a shop) drop the one in it and rebuild it and reinstall it?
Click to expand...
It's fresh rebuild new speed sensors new vssb
 
Sounds like the wrong ratio for the speed sensor. 91-93 were also known for having poor electrical contacts in the main harness plug on the transmission, which could be causing the shift issue, but I would look first towards the faulty speed reading as the cause of your shift issues. Ok, it is a rebuilt, but you didn't answer if you or a shop did the rebuild, that could address warranty issues for the cause of the shift issues. THE 4L80E (and pretty much any other transmission) expert on here is @THEFERMANATOR, you can take his answers like a Tablet coming down from Mt. Sinai.
 
Husker6.5 said:
Sounds like the wrong ratio for the speed sensor. 91-93 were also known for having poor electrical contacts in the main harness plug on the transmission, which could be causing the shift issue, but I would look first towards the faulty speed reading as the cause of your shift issues. Ok, it is a rebuilt, but you didn't answer if you or a shop did the rebuild, that could address warranty issues for the cause of the shift issues. THE 4L80E (and pretty much any other transmission) expert on here is @THEFERMANATOR, you can take his answers like a Tablet coming down from Mt. Sinai.
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A shop done it
 
Also, "rebuilt" can cover a lot of levels of servicing, from just slapping in new steels and frictions and calling it rebuilt, to total disassembly of the valve body and repairing the worn TCC valve bore and worn check valve seats, updating/upgrading the sprag and drum and bands, as well as replacing all solenoids and internal wiring harnesses and the main harness. You also would not believe how many times on reassembly the internal harness gets accidentally pinched and causes all sorts of problems, too.

I'm not trying to be snarky or an ass, but in order to figure out what could be wrong, especially over the internet and without being there, the more details given, the better.

N
 
Husker6.5 said:
Also, "rebuilt" can cover a lot of levels of servicing, from just slapping in new steels and frictions and calling it rebuilt, to total disassembly of the valve body and repairing the worn TCC valve bore and worn check valve seats, updating/upgrading the sprag and drum and bands, as well as replacing all solenoids and internal wiring harnesses and the main harness. You also would not believe how many times on reassembly the internal harness gets accidentally pinched and causes all sorts of problems, too.

I'm not trying to be snarky or an ass, but in order to figure out what could be wrong, especially over the internet and without being there, the more details given, the better.

N
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I used a scan tool and scanned and come up with about seven or eight different codes which are 13 oxygen failure 43 electronic spark control failure 39 torque converter clutch error 68 overdrive fault 86 solenoid b stuck on 85 unidentified ratio / PCM and also my heater is haywire
 
Husker6.5 said:
Also, "rebuilt" can cover a lot of levels of servicing, from just slapping in new steels and frictions and calling it rebuilt, to total disassembly of the valve body and repairing the worn TCC valve bore and worn check valve seats, updating/upgrading the sprag and drum and bands, as well as replacing all solenoids and internal wiring harnesses and the main harness. You also would not believe how many times on reassembly the internal harness gets accidentally pinched and causes all sorts of problems, too.

I'm not trying to be snarky or an ass, but in order to figure out what could be wrong, especially over the internet and without being there, the more details given, the better.

N
Click to expand...
Also the heat indicator for heat settings all flash all the time
 
@THEFERMANATOR is our transmission guru on here. I'm sure somewhere along the line he'll pop in here with a definitive answer, but from what your transmission codes are saying, there's definitely an internal electrical issue and the 'slippage' code could very well be related to a reluctor wheel issue for the output speed sensor or an internal wiring (pinch) issue.
 
Husker6.5 said:
@THEFERMANATOR is our transmission guru on here. I'm sure somewhere along the line he'll pop in here with a definitive answer, but from what your transmission codes are saying, there's definitely an internal electrical issue and the 'slippage' code could very well be related to a reluctor wheel issue for the output speed sensor or an internal wiring (pinch) issue.
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Could it be the solenoids that's the only thing I can think of that was not changed
 
Seems like I remember reading somewhere that engine issues can affect the transmission. Put it in limp mode etc
 
His typing. He said you'll have to wait for @THEFERMANATOR, our transmission expert, to see he's been tagged and chime in on this thread. Do NOT just start throwing parts at it. Also, you do not have to hit the "Reply" any time you answer, as that quotes the previous person. Just go down to the box below this one and start typing.

What ak diesel was referring to about engine issues is this. If you have a bad engine temp sensor (not the gauge sensor) it will tell your Transmission Control Module (TCM) your engine is too cold and not allow it to stay in Overdrive.

Also, are these all new codes since the rebuilt tranny was installed? That is, did you clear them before the first test drive? Fresh codes are much more helpful than a bunch of stored ones from who knows when. You show a code for a bad O2 sensor in the exhaust and an issue with your spark timing. Transmission issues are the torque converter clutch (did you get a new torque converter in the rebuild, or did the shop reuse the old one?). The overdrive fault code could be several things that are preventing it from shifting into/staying in overdrive. The Solenoid B stuck on could be a couple of issues, from bad solenoid to pinched harness internally to bad pin connections in the main plug on the side of the transmission. The ratio error means that the output shaft isn't rotating the right number of times to the input shaft. That can be caused by internal slippage OR the wrong reluctor giving a false reading to the output shaft sensor and which could also be responsible for your whacky speedometer readings, and shifting issues.

Fresh codes are always a must. Also knowing what the shop did for the "rebuild" is a must, too, as I said above. There's a helluva difference between just slapping in a new set of steels and frictions and calling it "rebuilt" and doing a true rebuild and putting in a new torque converter, going through the valve body and upgrading all known weaknesses like the TCC actuator issues, check ball seat issues, new solenoids and solenoid wiring harness, new main wiring harness heavy duty sprag and drum, improved reverse band, etc. Did the shop do a static function test on the tranny after they were done, or did they just slap it together, called it good and send it out the door? I won't even get into the competency of the shop/technician doing the work.
 
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