lq4/4l80e stalls in gear
09-24-2015, 07:53 AM
#1
Staging Lane
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lq4/4l80e stalls in gear Have a lq4 that i put into a 1983 chevy C10 truck.
-stock bottom end
-243 heads with BTR .660 dual springs
-TSP 228R cam
-ls7 lifters
-headers
motor was originally a 4l80e, im assuming a 4wd version (came from a truck) and i put a 2wd 4l80e behind it. for now i have the stock convertor in the tranny. the issue is, whever i put the C10 in drive or reverse, the motor stalls out. In park it will udle and rev fine, and same with nuetral.
I have HPtuners and according to the scanner, the TCC lockup is off, althought my first thought is that the TCC lockup was staying on. which still could be the case if its stuck inside the tranny. I was told the tranny worked before being pulled. also odd which may be related is on the HPtuners display screen, if i move the truck the speedo doesnt seem to move.
any ideas as to why it wont run in gear? is the stock stall convertor engaging and killing the motor? or do you think theres an internal tranny issue.
-stock bottom end
-243 heads with BTR .660 dual springs
-TSP 228R cam
-ls7 lifters
-headers
motor was originally a 4l80e, im assuming a 4wd version (came from a truck) and i put a 2wd 4l80e behind it. for now i have the stock convertor in the tranny. the issue is, whever i put the C10 in drive or reverse, the motor stalls out. In park it will udle and rev fine, and same with nuetral.
I have HPtuners and according to the scanner, the TCC lockup is off, althought my first thought is that the TCC lockup was staying on. which still could be the case if its stuck inside the tranny. I was told the tranny worked before being pulled. also odd which may be related is on the HPtuners display screen, if i move the truck the speedo doesnt seem to move.
any ideas as to why it wont run in gear? is the stock stall convertor engaging and killing the motor? or do you think theres an internal tranny issue.
09-24-2015, 10:28 AM
#2
Copy and pasted this post from another forum. Sonnax makes some of the best transmission parts in the world, so I think what this man has to say is at least worth some consideration. It aligns almost totally with what we have seen from past experience with the 4l80.
-Brian
"Symptoms like this are common with 4L80E. The pumps are marginal to begin with and if asked to make higher pressure this symptom is more likely. Basically what is happens is at idle rpm's the pump is not able make 100% of the pressure it is calibrated to. As a result (by design) it restricts oil into the converter. Oil flow is needed in the converter to keep the TCC piston released. No/low oil flow and the TCC piston drags on resulting in symptoms like you describe. This can also be caused by a restricted cooler system due to pinched cooler line, restricted cooler, or wrong bushings in transmission etc. Things that will help are. . .
- Make sure pump clearances are perfect.
- Reduce unnecessary internal leaks that waste pump volume.
- Lower line pressure at idle.
- Increase idle rpm.
- Verify correct cooler oil flow, http://www.sonnax.com/pdfs/76-SonnaF...-E-Normal-Poor
- If not already done, add a line pressure to converter charge circuit oil path, to help keep the converter circuit charged with oil. This can be done by drilling a ~.040" hole between passages in the pump, or by installing this valve --> http://www.sonnax.com/parts/1989 In most units this valve can be installed without removing transmission.
If you are certain the TCC is dragging, my suggestion is to check with the builder to see if a line pressure to converter charge circuit oil path was added when built. If it has not, work through list above, if not install valve and check cooler flow etc."
HTH
Gregg Nader
Sonnax Tech
-Brian
"Symptoms like this are common with 4L80E. The pumps are marginal to begin with and if asked to make higher pressure this symptom is more likely. Basically what is happens is at idle rpm's the pump is not able make 100% of the pressure it is calibrated to. As a result (by design) it restricts oil into the converter. Oil flow is needed in the converter to keep the TCC piston released. No/low oil flow and the TCC piston drags on resulting in symptoms like you describe. This can also be caused by a restricted cooler system due to pinched cooler line, restricted cooler, or wrong bushings in transmission etc. Things that will help are. . .
- Make sure pump clearances are perfect.
- Reduce unnecessary internal leaks that waste pump volume.
- Lower line pressure at idle.
- Increase idle rpm.
- Verify correct cooler oil flow, http://www.sonnax.com/pdfs/76-SonnaF...-E-Normal-Poor
- If not already done, add a line pressure to converter charge circuit oil path, to help keep the converter circuit charged with oil. This can be done by drilling a ~.040" hole between passages in the pump, or by installing this valve --> http://www.sonnax.com/parts/1989 In most units this valve can be installed without removing transmission.
If you are certain the TCC is dragging, my suggestion is to check with the builder to see if a line pressure to converter charge circuit oil path was added when built. If it has not, work through list above, if not install valve and check cooler flow etc."
HTH
Gregg Nader
Sonnax Tech
09-24-2015, 11:12 AM
#3
A couple things besides what was posted
Sometimes a larger cam and stock converter don't work together
If you try and raise the RPM's in gear, will it stay running
It may need tuning in gear, IAC, etc, if the clutch isn't locking
The truck is a mech speedometer, trans is for an elect one-you need an adapter
Sometimes a larger cam and stock converter don't work together
If you try and raise the RPM's in gear, will it stay running
It may need tuning in gear, IAC, etc, if the clutch isn't locking
The truck is a mech speedometer, trans is for an elect one-you need an adapter
09-24-2015, 11:19 AM
#4
Staging Lane
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as far as the speedo. im refering to just on HPtuners its not showing a speed on the HPtuners scanner display.
if i put it in gear, foot on the brake, and touch the gas a little, yes it will stay running.
also should note its a DBW setup if that matters.
Brian I will try to work through some of those.
if i put it in gear, foot on the brake, and touch the gas a little, yes it will stay running.
also should note its a DBW setup if that matters.
Brian I will try to work through some of those.
09-24-2015, 02:07 PM
#5
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I think im gonna snag another tranny and swap it in and see if my problems continue. then i can narrow it down to being that tranny or not. found another for 300 bucks.
