Tranny Woes...4l60e experience needed

**liftedz71** · 05-06-2006, 08:31 PM

Well my dad and i have installed a new transmission in my truck but now have some problems that are unclear. I put a vette servo, billet 4th servo, 3000 stall converter and a transgo shift kit in my 4l60e. I immediately noticed that the truck takes much more throttle to get it up to speed and it will roll backwards (on a slight incline) when it used to not move at all, with foot off of throttle. Is this from my converter or the internal transmission components? I have no OD it seems, however i can feel the Torque converter lock but the tranny doesnt shift into OD. Also i got the DTC code p1870 which from what i have read is related to tranny slippage...yea

The only thing i could think of is the 4th billet servo doesnt have enough travel in the pin causing it to avoid OD. The tranny was rebuilt by AAMCO and my dad and i installed the shift kit and servos as well as putting the tranny in....they told us to bring it in when we are done so they can check it over, but i would like to have an idea as to what it is doing before i take it in. Any ideas or advice?

**liftedz71** · 05-07-2006, 06:05 AM

Bump Bump.....no ideas?

**CoonToot** · 05-07-2006, 07:06 AM

Originally Posted by liftedz71

I immediately noticed that the truck takes much more throttle to get it up to speed and it will roll backwards (on a slight incline) when it used to not move at all, with foot off of throttle. Is this from my converter or the internal transmission components? I have no OD it seems, however i can feel the Torque converter lock but the tranny doesnt shift into OD. Also i got the DTC code p1870 which from what i have read is related to tranny slippage...yea

The only thing i could think of is the 4th billet servo doesnt have enough travel in the pin causing it to avoid OD. The tranny was rebuilt by AAMCO and my dad and i installed the shift kit and servos as well as putting the tranny in....they told us to bring it in when we are done so they can check it over, but i would like to have an idea as to what it is doing before i take it in. Any ideas or advice?

That's from the converter. Mine did the same thing. Kinda freaky, but it will go back to 'normal' after some miles on it.

Originally Posted by liftedz71

I have no OD it seems, however i can feel the Torque converter lock but the tranny doesnt shift into OD. The only thing i could think of is the 4th billet servo doesnt have enough travel in the pin causing it to avoid OD.?

If you have 1,2, and 3 but no OD, then that 4th gear OD servo is most likely the culprit. Check to make sure the servo is in the right way. I think it will fit both ways, but only one way will get you OD.

**liftedz71** · 05-07-2006, 07:22 AM

So how many miles before your converter acted normal....i have already drove it maybe 40 miles without change. The Servo does make sense and was the first place i was going to look before going into the valve body again, could this make the DTC P1870 come on? From what i have read i wouldnt think so but if the tranny is attempting to go into OD but there isnt enough clearance on the servo pin would this make sense. Could it cause the continuos slippage and code? I have the sonnax 4th OD Servo and followed the instructions, it seems there is only one way to put it in. Any other input?

**CoonToot** · 05-07-2006, 07:27 AM

Originally Posted by liftedz71

So how many miles before your converter acted normal....i have already drove it maybe 40 miles without change. The Servo does make sense and was the first place i was going to look before going into the valve body again, could this make the DTC P1870 come on? From what i have read i wouldnt think so but if the tranny is attempting to go into OD but there isnt enough clearance on the servo pin would this make sense. Could it cause the continuos slippage and code? I have the sonnax 4th OD Servo and followed the instructions, it seems there is only one way to put it in. Any other input?

Took about 500 or more...give it time. Can't help on the code, as I never have had one thrown. I had my tranny built/modded at a local tranny shop but had the same issues (short the code) come up last time in. I have the SOnnax servo as well, but it didn't require any pin length adjustment...the tech said the servo was put in incorrectly. He could have meant backwards, could have menat in the wrong place or order too. Dunno the specifics, but I would pull the servo and triple check your install. It's defiantely not a solenoid if you have 1,2 and 3.

**liftedz71** · 05-07-2006, 07:36 AM

Ok cool...so that makes me feel somewhat better on that note. After the 500 miles did you actually notice the TC change or was it just having to get used to it. From my understanding i didnt think a higher stall would cause the truck to become harder to move....(1000RPM from stop to get it rolling) when at 500RPM (idle) it would roll fine with my older converter.

**CoonToot** · 05-07-2006, 07:52 AM

Originally Posted by liftedz71

Ok cool...so that makes me feel somewhat better on that note. After the 500 miles did you actually notice the TC change or was it just having to get used to it. From my understanding i didnt think a higher stall would cause the truck to become harder to move....(1000RPM from stop to get it rolling) when at 500RPM (idle) it would roll fine with my older converter.

You are experiencing the "looseness" of a higher stall. It DOES take more RPM to get the same effect as when you had the stock converter in there. After a while it will feel strange to drive in a stock truck...

**liftedz71** · 05-07-2006, 09:38 AM

ok so does the TC also change the final OD RPM's? Now my OD RPMS with the 3000 stall converter is around 2100 at 50mph where with my stock TC it was 1400RPM's at 50 mph. Will a TC do this?

**Atomic** · 05-07-2006, 09:59 AM

if you got a lockup converter then no, your od rpms shouldnt change any.

**liftedz71** · 05-07-2006, 10:03 AM

Thats what i thought....so i've been sold the wrong TC then....now i have the new stock TC that came with my rebuilt transmission....does anybody think changing it will do anything?

**airdeano** · 05-07-2006, 10:18 AM

as per SIS DTC P1870:
Circuit Description
The VCM monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +20 RPM.

When the VCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.

Conditions for Setting the DTC
DTC P1870 sets if the following conditions are met for three TCC cycles with reported excessive TCC slip conditions, two consecutive times.

No TP DTCs P0122 or P0123
No VSS Assy. DTC P0502
No TFT Sensor DTCs P0712 or P0713
No TCC Sol. Valve DTC P0740
No 1-2 SS Valve DTCs P0751 or P0753
No 2-3 SS Valve DTCs P0756 or P0758
No TFP Val. Position Sw. DTC P1810
No TCC PWM Sol. Valve DTC P1860
The engine speed is greater than 450 RPM for 8 seconds.
Not in fuel cutoff.
The engine torque is 50-450 lb ft.
The gear range is D4.
Not in 1st gear.
The TP angle is 9-35%.
The TFT is 20-130°C (68-266°F).
The TCC is ON for 5 seconds.
The TCC is at maximum apply for 5 seconds.
The TCC slip speed is greater than 130 RPM.
All conditions met for 7 seconds
Action Taken When the DTC Sets
The VCM inhibits TCC engagement.
The VCM commands maximum line pressure.
The VCM inhibits 4th gear if the transmission is in hot mode.
The VCM freezes shift adapts from being updated.
The VCM illuminates the Malfunction Indicator Lamp (MIL).
Diagnostic Aids
Internal transmission failures could set a DTC P1870.
A TFP Valve Position Switch malfunction could set a DTC P1870.

HTH

airdeano

**liftedz71** · 05-07-2006, 10:26 AM

ok tell me if im wrong airdeano....if the TC i was sold is not a lock-up like the stock one the computer thinks it should be locking up or is trying to....which then would set the p1870 code? Or is this something valve body related to the tranny? Everything shifts great other than the slow roll to get it moving and the higher RPM in OD. I guess i will try the stock converter and see if i get a code and/or a lower OD RPM. If its the converter then i will just keep it stock.

**airdeano** · 05-07-2006, 10:47 AM

yes... if a non-lockup is installed yes youd have slippage errors
because the pcm commands TCC, it knows TCC exists, but the action
isnt noticed. therefore slippage +20rpm will be noticed.
but alot of things has to happen to engage lockup.
recheck the wiring, brake switch,
3000rpm is alot of stall for a torque peak of 2800rpm vortec.
2500rpm would have been a better choice.

airdeano