Tranny slip? Electrical or mechanical? Please help asap

This vehicle comes with several transmission options. And it comes in AWD or FWD. The conventional automatics are the 6T30/40/50 line, or the 6T70/75 line. If you have one from the first set, from what I see the transmission doesn’t need to be removed to service the input speed sensor; however, the valve body has to be removed, and access to that requires the front transmission mount be removed. The shop might find it easier in the long run to just remove the transmission, thinking once they remove the valve body they’ll probably find something else in need or repair. I don’t see a procedure to replace the transmission filter, but the parts cost is over $500, so it probably isn’t designed to be replaced except during a major service or rebuild. The filter seems to be located inside the torque converter/fluid pump housing; i.e. probably not a simple thing to replace. (For comparison, it takes about 5 minutes to replace the trans filter once the pan is removed on my truck.)

Its at my regular mechanic’s now, if it helps you to differentiate, I have the 2011 SLE 2.4
I know he plans on pulling the top half as you mentioned and replacing the input speed sensor and servicing the filter as needed. I would greatly appreciate any info you can give on what he’ll be looking at. He does accept my input… Wyattspoppa

Hey, it’s a sealed unit, only “serviced” when issues arise, not even a dipstick

Next time you are talking to your shop about the transmission work they are doing, ask which transmission model it is. I expect the transmission case has a label of some kind.

I’ll do that in the AM George, they actually had it open and installed the Input speed sensor I picked up at Napa (I got the right OEM part!). I want to be frank with you, my mechanics are both capable men and I’ve used them for years, but they seem to work just on tons of hands-on experience and not guys who study shop manuals which is partly why I sought your expertise. The good news is we made the right call, this wasn’t mechanical, which saved me a $3000+ rebuild I just couldn’t afford with my wife’s surgery Monday, my concern is after following your notes and dozens of hours of my own study, what can they miss before they close up the Tranny case? Can they still run OBD codes before they zip it up? They are people I call friends and they’re very generous with me, but dropping the tranny costs labor hours they have to account for at “Tuneup Masters”, if something is missed, it’s not like I can expect them to drop it again “gratis”. This will be about whether the work gets the tranny and it’s sensors playing nicely with the PCM, if they miss something…bad news for me. I do know their scanner is a $5,000 “heavy hitter” so it should be able to diagnose and reset, but I’d greatly appreciate any thoughts you’d have on the matter before I let them put it back George. Oh, and I got misinformation from the dealer, they told me $199 to “service” the filter, they charge $500 so it’s the one you said, it couldn’t be accessed easily. What advice would you give before “stitching it back up”? Inspect wiring harnesses I assume, running the scan (if possible while it’s open), replacing the filter and fluid (if the filter isn’t some special $500 component). Thank you for every moment of your valuable time, this kept my family from more trouble than I can say.

Thought you’d get a laugh out of this, taking my wife to work in my '96 Olds Aurora today (you’ve helped me with many times) and my entire exhaust falls off the damn car, it falls off, it fall the hell off! Mind you, this is a Cadillac Northstar V8 so it’s a dual-pipe exhaust, maybe 8 feet long from about the front tires to the trunk…massive! So now I had both our cars in the shop at the same time, rented one. It turns out the whole system was hanging from the undercarriage strung up by bailing wire (glorified coat hangers). My guys reinstalled it for $100!!! Bet a dealer/name-brand shop would have charged me $500+

So the transmission no longer slips in reverse?

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Is this the transmission where the mechanic at the shop found the fluid was black and toasty, and therefore didn’t want to recommend anything less than a complete overhaul or replacement?

I’m asking because OP has started quite a few threads lately, and I’m having a hard time keeping them separated, so to speak

It never rains but it pours! lol … If it is any consolation I had the exhaust system fall off my truck before, when I lived in Colorado snow country. Fell right off into the street behind me. Clunk. clunk. I stopped & picked it up and put in in the back of the truck and drove to the shop to schedule a new one. Teenagers kept trying to engage me in drag races at stop lights b/c of all the exhaust noise my truck was making :slight_smile: .

It sounds like you got the transmission input speed sensor problem solved. Good for you. If I had that problem at this point I’d just ask them to do what you suggest above: check the wiring harness to make sure everything connected properly, drive it for a week or so then bring it back to double check for any remaining engine and transmission diagnostics codes. Refill with fresh fluid of course. Absent any symptom definitely related to the filter, I wouldn’t mess w/the filter.

Your advice and guidance were largely why I didn’t concede to a rebuild without extensive investigation, thank you George. We were facing $3000 plus we didn’t have with my wife’s surgery on Monday, and then my 22 year old beast, the Aurora. You’re so right about the “rain”, when I got out of my car and saw my massive exhaust system laying on the ground, I literally dropped to my knees and was prepared to come unhinged, but my wife was there so my pride saved me. My mechanic put the muffler back on for $100, pretty reasonable.
PS A funny thing, my gas gauge hasn’t worked in 10 years, the day he put the muffler back on and it’s fixed (he told me he had to hook up a few things that came disconnected), I didnt know it was attached. Oh, and my gas mileage instantly dramatically improved, so it was obviously partially disconnected for a long while. I was getting a pathetic 13 mpg, now closer to 20 it appears. Why?

Hey Nevada, we won’t know for sure until they zip up the tranny today, but I can tell you my mechanic drove it in both forward and reverse when the “Schister” who owned the tranny shop told me it was now dead. I had a feeling it was electrical because it still drove perfectly normal and then the gears would turn off like a light switch, no grinding or slipping sensation, just like someone turned it off. While they had it open, my mechanic went ahead and put in the new OEM input speed sensor I bought anyway, why risk it if it might be bad, right?
Even from a friend/mechanic it still will probably cost $500 in labor to open up the case a 2nd time, only losing $40 if the sensor was ok

I apologize once again sincerely for not keeping it organized, I was panicking with my wife having surgery on Monday and both our cars died, one a possible $3000 repair, the other my entire exhaust system (dual pipe, 7 foot long) just fell off my car and all this happened in 1 week. I will be more careful to follow protocols in the future

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The wife’s surgery went as well as could be expected, I hope . . . ?!

The fuel gauge sender unit is a float like contraption located inside the fuel tank, and there’s a wire from it to the fuel gauge. Probably that wire had disconnected itself for some reason, and the exhaust guy noticed it and reconnected. The fellow who sold me my truck (used, one year old) told me the fuel gauge for one of the tanks hadn’t worked in the entire year he owned the truck. I took a quick look and the wire had become disconnected under the dash. Stuff like that happens. As far as improved mpg with the improved exhaust system, might be the exhaust leak was affecting the o2 sensor reading. The computer uses that to set the fuel to air mixture. Modern electronic fuel injected engines rarely run well if there’s a leak in the exhaust system.

Wishing you best of luck with your wife’s medical problem and your vehicles.

It has been two weeks, how is the transmission performing?

Hey GSJ, I meant to thank you for your kindness and well wishes. Back when we looked at this, an OBDII showed I had 2 failed O2 sensors, one up and one downstream. My car as you know needs a water pump I’m replacing on Monday, but the last 2 scans detected nothing, and I never got around to the O2 sensors? I think it’s idling a little high (around 800) and just not as smooth as normal, can your ECM go bad and still allow your car to run properly? There should be no way I have no fault codes with all the stuff this car has going on…
Thank you

Forget the ECM . . .

I’d say most engine control modules get needlessly replaced, because the mechanic . . . or whoever is working on the car . . . didn’t actually find the root cause of the problem(s)

Just because you have no fault codes doesn’t mean there’s no problems

Here’s just a short list of faulty components that I’ve replaced that caused driveability problems, yet they didn’t generate a check engine light or any kind of fault code

crankshaft position sensor
spark plugs
coils
ignition wires
mass air flow sensor
idle air control valve

If your car’s not running correctly, but there are no codes, there’s only one thing to do . . .

Find an experienced, patient and competent mechanic to work on the car

Note that it’s possible to have an experienced and patient mechanic, but he’s nevertheless incompetent

I’ve known a few of those

It’s also possible to have somebody that’s impatient, and instead of being systematic, he skips towards the end of the trouble tree, or replaces the engine control module, because he can’t figure it out, and thinks that MUST be it . . . and then it doesn’t solve the problem, after all

Intelligent reply and I did not know you could have so many possible issues without generating fault codes, thank you