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Fellas...part two of Transmission issues from a previous post...

 

Out of nowhere, 2007 2500HD gas job - 4L80e - started throwing me a Transmission slip code  (two of them   ).  Transmission fluid nice and clean, next to no debris on the magnet/etc.  270km on the truck but ran and shifted perfect the last couple years no problem.

 

I had a shop look at it since it really seems electrical to come out of the blue like that.  They figured the same and suggested TCC solenoid - changed it - same symptoms.  Clear codes, shifts great.  Go on the highway and can tell it’s not locking up.  Codes again.

 

If I drive it in 3rd - same distance no issues on the highway.  No codes.

 

So....what’s next guys?  Is there a 3-4 solenoid to change??  Some sort of an OD lock up solenoid aside from the TCC since it seems to be the OD/4th situation that’s causing the codes.

 

Or is this looking toward a converter??  Had lots of other trucks with converter go out and they didn’t come out of nowhere and burnt up fluid.

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Mine has a similar issue, the converter is delaminating and sending metal all through the trans and pump. Needless to say I took it to a trans shop and it’s going to need a new converter, new pump and bell housing as well as total rebuild. $3000.. lovely 6l90. I changed the fluid and filter and it helped some but it’s not right. As yours is as well, it started out of no where, never had previous issue.


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Big O, what are the codes you were getting?  It certainly could be the OD clutches have finally be used up, after 270k...

 

I would lean more towards that than the converter, given that the converter seems to be locking up in 3rd.

 

But I would suggest using a tech ii or autogenuity or something that can read the transmission computer and tell you when the TC is locked, what gear it's in, and transmission input and output speeds, to more precisely know whats happening in the transmission.

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Hey Davester...Codes I’ve seen were commonly P0894 and on one or two occasions a P0741 code.  Read what both were and the P0741 got me thinking more.

 

I’ll maybe have to take it to a specific trans shop vs general mechanic or my plain Jane scanner.  

 

And yeah - it’s got 270 so could just be simply due for a rebuild but man, everything has just worked so well and clean/without any signs of overheating or debris.  But I also know shit wears out.  

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TECH 2 Diagnostic scanner. This can run each component that is electrical.

 IF it was my truck, I would do the BCM ground first, If its on the frame under the DS like older trucks, then look into if it has a TCM and T-shoot that.

 Stock thermostat and stock trans cooler will only go so far, the transmission start to break down after 200 degrees, and stock stuff keeps it close to 200 ( oF)

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Thx Bruce...I’ll see if my Trans guy in town has a Tech 2 or similar scanner that’s more capable.......

 

as for temps, I’ve not yet seen anything above 140.  And I’m watching it like a hawk (weekend truck - not primary) to make sure it doesn’t go anywhere near past 200

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Well - the verdict is in.  I had the transmission tech guys come along for a drive with their Tech Scanner...and he's 99.9% that the OD clutch plates have simply run their course.  Everything he could view was signalling that the right messages are being sent and that the transmission is trying everything it can to lock up the converter in OD - but not happening.  He also said that it's typically what he's seen and that they may not show any symptoms or slowly have this happen...they just eventually fail.


SO - - - I'd love to hear a few opinions on whether or not to replace just the converter (approx. $1-1,200 with labor), or if I should replace the whole transmission as I can get a rebuilt with warranty ($23-2,500 with labor) since all the other tranny components also have 270,000km of wear and tear.  It seems that the converter is typically what fails as it is continually slipping and locking/etc., and there was nearly nothing for debris in the pan or on the magnet and the fluid looked like new so aside from this slippage issue occurring, before that the tranny worked perfectly. 

 

Saving over $1000 would be really great right now - but having to turn around and spend the $2500 again within a year because of some other failure is not.  So just wondering if guys have done just the converter with good/fair results with the 4L80e or if they've had the rest of the tranny grenade within 20,000km afterward???

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If the OD clutch plates are gone, then the transmission needs to be worked on (as the OD clutch is in the transmission).

 

I would first try to figure out why the torque converter seems to be able to lock up in 3rd, but not in OD.  Is in the OD clutches slipping when the extra power going into the transmission as the converter locks up, or is the OD clutch not slipping, but the converter no longer can lock up with the extra torque going through it in OD, or is it some internal transmission problem, where when the OD clutch is engaged, it can't get enable the converter to lock.

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Thanks for the reply Davestar - I'll go back and chat more with the tech about what you mentioned above and see what they say or what they can do as well. 

 

I may be misinterpreting what he was meaning, since he said he was quite familiar with the issue and given that I haven't been driving it for an extended period with this happening, having clean fluid, and little to no debris on the magnet - he said that it was likely that changing the converter out would be a fair solution.  No guarantee......which is still the kicker of course.

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