No Drive - 3100 auto

[tlanger5]

Heres my prob - my tranny throws a code about a transmission slip. It ALSO does not shift into Drive. If I put it in drive, it will drive, but only shift up to 3rd gear, and when I take my foot of the gas pedal it seems like the transmission disengages or something because the rpms drop down to idle level and the car coasts without any resistance at all...like it just coasts like it is in neutral. I think the tranny must be completely dinked - what does everyone think? Thanks.

[rixGAphx]

'96 V6, 12-yrs old, so about 145k miles?
You've gotten good service out of this old gearbox, time to have some major service or replacement :(

You've checked the fluid level, and it's fine. Right?

How long sice the fluid and filter were changed? (Shoulda been done every 50-60k miles; every 30k in 'severe' driving conditions).

With the engine 'cold', open the hood and look down to your right.
The tranny is beneath the engine air intake tube.
Almost directly below the throttle body is an electrical connector with 5-7 wires, plugging into the tranny.
The connector is kinda complicated, a bit like a chinese wood-block puzzle.
To disconnect it, you must pull some pins or slide a clip or similar, then release some tabs; while trying not to break anything.
Unplug this connector from the tranny, and replug-unplug-replug several times.
This action will partially-clean dirt and corrosion from the pins and sockets, and *may* restore connections that *might* be the cause of the problem.
This is a longshot, and I doubt it will help; but better to try it now, than lay out $$$ to find out the problem was a loose connector.

There is absolutely nothing else you can do as a car owner or DIY mechanic with this tranny.

So go to a reputable tranny shop and have them diagnose it.
They *may* get some additional data about the 'slip' from the PCM (Powertrain Control Module, the engine-tranny 'puter), but that's doubtful.
This tranny only uses the PCM for shift points and torque-converter lockup, and doesn't have any true sensors to tell the PCM what's happening internally.
It only 'senses' a slip, because it knows the engine rpm (tachometer), the gear, and the road speed (electronic speedometer) and thus can figure-out what the rotational difference *should* be vs. what it is.

The shop will give you an estimate, or range of prices for different repair operations, based on road-test and some other tinkering.
Make a sound economic decision based on those prices, not on fear of what they *might* be.
You can always just drive home from the shop, or even spend a few bucks for a tow, if you don't like/can't handle their prices.

The problem is that other than dropping the pan and replacing the filter, there is absolutely NOTHING that can be done for this tranny without completely dropping it from the car and going inside it with specialized knowledge and tools and test equipment.
So even the shop can't know precisely what's wrong unless:
* Their troubleshooting charts identify an EXACT problem based on symptoms; or,
* They drop the tranny and go inside.
Now we're talking $$$ for labor, about $80/hr.
About 3 hours for the R&R operation itself.

The problem *might* be as simple as some dirt or debris stuck in fluid passages, or just a faulty pump.
BUT, once you've gone to the trouble/expense of entering an OLD tranny, you might as well replace the parts expected to wear (seals, bands, clutches).
Since torque converters wear as they're driven tens of thousands of miles, a new one is in order.
And the three electronic solenoids that control shifting, especially the TC clutch solenoid, should be replaced.
Altogether, I'm GUESSING about $1000S1200, assuming nothing is actually broken.

Hope this helps,
-Rick

PS: Have you checked your battery cables recently?
There's a write-up in the FAQs of this forum.
A tranny 'slipping' in first gear is one symptom of poor battery power, often caused by loose/dirty/corroded cable ends that prevent good power flow.
The tranny's three electronic solenoids need good power for proper operation.

But poor battery cables usually show several other symptoms, so I doubt this is your problem (unless you have other symptoms you haven't mentioned).

PPS: When you disconnect the battery cables for service, after 10 minutes without power the PCM will erase its stored codes.
So you'll hafta drive around again to set/store some new codes, before going to the tranny shop.

[HeyDace]

P1870 "component slipping" is a common code for GM trannies. I'm sure that is the code your getting. Have it checked out at a transmission shop or even your favorite repair shop.

[tlanger5]

Hey guys, I thought I would post what was wrong with my transmission. According to the mechanic, it was a stripped over-drive hub.. supposedly it was completely stripped and thats why I have no overdrive. He said that there is no known cause for it. So anyway, hopefully this does not happen to anyone because its goin to cost me a pretty penny - like 1100 before taxes - I went with him repairing the old one instead of putting a used one in because then it will be reliable. Anyway, hopefully this was useful!

[tlanger5]

Hey guys, I thought I would post what was wrong with my transmission. According to the mechanic, it was a stripped over-drive hub.. supposedly it was completely stripped and thats why I have no overdrive. He said that there is no known cause for it. So anyway, hopefully this does not happen to anyone because its goin to cost me a pretty penny - like 1100 before taxes - I went with him repairing the old one instead of putting a used one in because then it will be reliable. Anyway, hopefully this was useful!

[gobraves00]

same was wrong with mine, but i went with a used one for 350 since i just drive it to shows and home, its not my daily driver.it also helps to have a father with his own shop so i could do the work myself and save on the labor