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'99 Tahoe 4L60E trans P1870 code


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Wayne67vert
Novice

Mar 4, 2015, 3:47 PM

Post #1 of 14 (3733 views)
'99 Tahoe 4L60E trans P1870 code Sign In

I'v got the 5.7 motor 2wd.

It's giving hard 1-2 shifts with a P1870 code. I had a local shop check it out today.

The readout shows slippage of 160 to 170 rpms. The tech said this is excessive.

My Tahoe has 106K miles on it.

Is this something to sway me to a rebuild rather than a valve body repair?

Thanks,
Wayne


gsferraro
Veteran

Mar 4, 2015, 6:16 PM

Post #2 of 14 (3717 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Hello,
The 1870 is a tcc slip code, You can try a valvebody repair first if you like, depending on how bad it is, it may or may not fix the problem. this code is usually due to a worn bore. The way the valve train is set up is, the isolator valve first spring in the middle and the converter reg valve against the bore plug. There is a company called transgo that sells a drop in fix for this problem. Your trans is called a 4L60E. I usually vacuum test the valvebody to see how worn it is, if its bad i use oversized valves in the bore. If the code comes back your converter clutch may be to far gone. How long is this code in your system for? Gary


Wayne67vert
Novice

Mar 4, 2015, 6:58 PM

Post #3 of 14 (3714 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Thanks for the reply Gary.

I bought the truck in November. I didn't notice this issue until I took it on a 4 hour road trip after Christmas.

It only happens when the trans gets hot after driving on the interstate for maybe 20 minutes.

I've read about the valve replacement to correct the p1870 code and hard shifts.

My concern is the amount of slippage indicated. Is it too excessive?


gsferraro
Veteran

Mar 4, 2015, 7:17 PM

Post #4 of 14 (3711 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Yes the slip is to high, thats why the code is settting, an acceptable rpm slip on a torque converter slip is 10 rpm or less. You have a hard 1-2 shift because the computer is rasing line pressure. Gary


Wayne67vert
Novice

Mar 4, 2015, 7:20 PM

Post #5 of 14 (3709 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

OK, Am I wasting my time trying to put a valve kit in?

Should I just go for a rebuild?


gsferraro
Veteran

Mar 4, 2015, 7:25 PM

Post #6 of 14 (3708 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Anytime a car comes into my shop with that code, i sell them a rebuild becuase there a many things that can cause this code, such as converter,pump bushing, stator bushing, tcc o ring. When they do the rebuild they should update the valvebody if it comes in with that code(i know i would). Are you familar with dropping the valvebody? Gary


Wayne67vert
Novice

Mar 4, 2015, 7:40 PM

Post #7 of 14 (3706 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

I've never done one, but I've rebuilt everything else on a couple of other vehicles I own.

I'm not looking to rebuild this my self. Auto Transmissions are still very spooky to me.

What do you feel is a reasonable price to pay for a rebuild?


gsferraro
Veteran

Mar 5, 2015, 3:54 AM

Post #8 of 14 (3691 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

i would say 1800-2000. I would get about that and im in new york. Gary


Wayne67vert
Novice

Mar 5, 2015, 6:24 AM

Post #9 of 14 (3684 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

The prices here (Central Florida) are a very wide range.

1000 from a small independent to 3000 for the big shop.


gsferraro
Veteran

Mar 5, 2015, 10:58 AM

Post #10 of 14 (3677 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Would they actually do an overhaul for 1000 or just a repair. Gary


Wayne67vert
Novice

Mar 5, 2015, 1:00 PM

Post #11 of 14 (3672 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Not sure.

I have it in a shop now doing a rebuild that is a low of 1200 to a high of 1800. It all depends on what needs replaced.

The owner answered my concerns and has many good reviews on line for a number of years.

my fingers are crossed!


(This post was edited by Wayne67vert on Mar 5, 2015, 1:01 PM)


gsferraro
Veteran

Mar 5, 2015, 2:10 PM

Post #12 of 14 (3669 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Let me know how it goes. Gary


Wayne67vert
Novice

Mar 10, 2015, 4:52 PM

Post #13 of 14 (3646 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Picked it up today after a rebuild.

Replaced: Converter, Torque converter clutch solenoid, pump, reverse drum.
Rebuilt the valve body, put in a shift kit and an overhaul kit.
12 mos, 12k mile warranty
$1725

Told me I would have lost 4th gear soon.


gsferraro
Veteran

Mar 10, 2015, 5:06 PM

Post #14 of 14 (3645 views)
Re: '99 Tahoe 4L60E trans P1870 code Sign In

Sounds good, thanks for letting us know. Gary






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