96 GP GTP valve body/transmission

[96fan]

P1870 cel code. I had read it usually has to do with the solenoids in the valve body. I thought I had read it could be changed fairly easy after dropping trans pan. So I bought a reman'ed sonnax upgraded valve body and of course after purchase I am now worried I misread/forgot and I'm looking for info for how big of a job it is to replace. Rough description of job and hours to complete a valve body swap is what I'm after. Or if I'm better off just returning the part to rock auto.

Also if I'm way off course on that code let me know. Issue is car seems to pulse similar to a cylinder misfire when in 4th gear low rpm under a load. Apply throttle,  downshift to 3rd and usually 3k rpms or more and no problem and it downshifts smooth. But to try to hold 4th at lower rpms under a load is has that issue. Thanks in advance for helping my stupidity.

[GTP091]

I’ve replaced the valve body on a 04 explorer. It did not fix the problem I had but was not a hard job really. The valve body pistons on my exploder were cracked and would leak down causing the bands to lose tension but not likely what you’re dealing with but I read it could be… The valve body replacement is Messy… you need to be very clean as you go. Keep a piece of cardboard nearby  and draw the bolt locations on it and stick em in so they all go back in the right spot. Have a 1/4” drive torque wrench available. 

you might want to do more troubleshooting first though.  Could simply need a fluid change or be other things. The valve body being bad is a culprit so I wouldn’t send it back yet. Read up if you can’t figure out a likely cause before you open it up, maybe get some more parts for a ‘while you’re in there’ scenario. I hate doing shit twice. The TCC solenoid and the TCC itself is also a culprit.
 

https://obd2pros.com/dtc-codes/p1870/

https://www.motor.com/magazine-summary/deciphering-gm-transmission-dtc-p1870-june-2006/

looks like YouTube has some diagnostic vids as well.

good luck man.

Edited September 23, 2022 by GTP091

[96fan]

Thank you

[55trucker]

8 hours ago, 96fan said:

P1870 cel code.

I think you're barking up the wrong tree......

1870 is a slipping TCC clutch situation, may or may not be in the valve body, the solenoid is not in the pan, it's in behind the rear trans cover.

The trans has to come out to  get that cover off. Now the reason why the clutch is slipping could be low pressure to the converter lock up shaft (diagnose the source), the clutch plate has worn off the friction material so it won't remain solid in place against the inside of the turbine impeller housing, the clutch plate bearing assembly is failing or the TCC solenoid is failing.

Edited September 23, 2022 by 55trucker

[96fan]

Thanks 55 trucker. Soo no matter which way this pie is sliced... trans has to come out. And at 150k miles ought just be rebuilt if it's getting pulled...

[55trucker]

Yeah, well, somewhere north of $2500 for a rebuilt trans doesn't make me fell all warm & fuzzy.

If you were able to find a good LOW mileage 4T60-E, but when it comes to salvage yards one doesn't know what the history is of the car it came out of.

[96fan]

Yeah same here. Hate to let the car go as is but not something I'm ready to put that kind of money on unfortunately. Thanks for the help. For now we will try new filter and fluid with some Lucas additive in it. I'll return the sonnax valve body.