6.0L/4l80e feels super weak after swap.
03-26-2016, 04:56 PM
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6.0L/4l80e feels super weak after swap. Swapped a good running LQ4 and 4l80e into our k1500 (4.10 gears, 38.5" tires). Motor and trans felt good in the donor truck. Trans never unbolted. Just a simple swap.
Truck doesn't feel like it has any torque. Yes, we lost a lot of trans fluid during the swap, but filled it back up. It really didn't want to fill. Keep dumping juice in, reads good (park/warm), take it for a drive and then it reads low (no, not leaking).
Just no torque at all. TCC slip RPM seems abnormally high on accelleration (ie: it'll easily do 1500-2000RPM while engine RPM is around 4000). In my 5.3/4l65e, TCC slip never exceeds 600 or so RPM.
Not throwing any codes. Output fitting (front) runs to top of cooler, then out cooler to top of rad, and out bottom of rad back to the rear fitting. Yes, we got the correct rear fitting for the 80 (has extra length beyond threads to made up to something...).
My 5000lbs XJ with the 5.3/4l65e, 4.56 gears, 35" tires does 0-60 in around 6.5 seconds which really ain't bad. The k1500 at about the same weight (possibly a touch lighter), with 4.10's and 38.5's is just feeling piggish. Doesn't feel any faster than the 4.3L/NV3500.
What'd we **** up? All I can think is that the TC just isn't filling up. What should we be looking for? Owner of the truck is all disappointed now after slowly hacking together the swap over 3 months, and it's finally running and sounds great, but has precisely 0 *****.
Truck doesn't feel like it has any torque. Yes, we lost a lot of trans fluid during the swap, but filled it back up. It really didn't want to fill. Keep dumping juice in, reads good (park/warm), take it for a drive and then it reads low (no, not leaking).
Just no torque at all. TCC slip RPM seems abnormally high on accelleration (ie: it'll easily do 1500-2000RPM while engine RPM is around 4000). In my 5.3/4l65e, TCC slip never exceeds 600 or so RPM.
Not throwing any codes. Output fitting (front) runs to top of cooler, then out cooler to top of rad, and out bottom of rad back to the rear fitting. Yes, we got the correct rear fitting for the 80 (has extra length beyond threads to made up to something...).
My 5000lbs XJ with the 5.3/4l65e, 4.56 gears, 35" tires does 0-60 in around 6.5 seconds which really ain't bad. The k1500 at about the same weight (possibly a touch lighter), with 4.10's and 38.5's is just feeling piggish. Doesn't feel any faster than the 4.3L/NV3500.
What'd we **** up? All I can think is that the TC just isn't filling up. What should we be looking for? Owner of the truck is all disappointed now after slowly hacking together the swap over 3 months, and it's finally running and sounds great, but has precisely 0 *****.
03-26-2016, 09:37 PM
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Yes. It is shifting though all gears and always takes off in first, but shift points are all very high and TCC slip is always high (way higher than I've seen on my 4l65e which runs minty). Everything feels like low trans fluid or low pressure. Can't get into 4th until around 100km/h. At city speeds, during cruising (around 60-70k) it'll stay in third even if we let off the throttle. I just don't know enough about these transmissions. Just went for a drive (20 minutes). Stopped to get groceries. Fire it back up and check the fluid level again and it shows low, but didn't have any fluid on us, so drive home. Get home, it's puking a little fluid out the vent and now shows full or over full. Dunno what to make of it. It all feels like low fluid, but then pukes fluid out the vent. I feel like I'm missing something obvious.
03-28-2016, 12:52 PM
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I agree, but does that explain the extremely high TC slip? I guess I haven't actually checked RPM's on the highway, but it sounds like he's at least 3500RPM in 4th at 100km/h, which should mean the TC slip is probably between 1500 and 2000 RPM, which doesn't make sense to me. If it was lacking power, it should gear down. I don't see how the TC should ever slip >1500RPM.
03-29-2016, 07:52 PM
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Warning: I have no experience with the 4L80e, but let me try to keep the conversation going....
To me it sounds like a combination of low fluid level and a converter that is seriously overheating due to excessive slip. That heat will cause the trans to puke fluid.
Perhaps the converter isn't getting enough fluid to operate properly.
I would first confirm that the trans cooler is connected and not clogged.
Perhaps one of the 4L80e experts knows if a clogged trans cooler cause your problems.
To me it sounds like a combination of low fluid level and a converter that is seriously overheating due to excessive slip. That heat will cause the trans to puke fluid.
Perhaps the converter isn't getting enough fluid to operate properly.
I would first confirm that the trans cooler is connected and not clogged.
Perhaps one of the 4L80e experts knows if a clogged trans cooler cause your problems.
03-30-2016, 10:36 AM
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It can, but I've verified the fluid is moving properly from trans out to trans in. Pumps real fast.
There are so many answers that almost make sense but none of them account for the fact that the thing is sitting at 30000 RPM at a light cruise, and that's all TC slip.
Oh, we did get it out wheeling the other day and it was feeling much better (I was behind him so I can only say that it sounded like the RPM's had come down). Wheeled all day and it was fine. Still too much slip, but much less than before. Appparently on the way home though the RPM's came back up. Dude sounds like he's in full race mode just to maintain 60km/h.
There are so many answers that almost make sense but none of them account for the fact that the thing is sitting at 30000 RPM at a light cruise, and that's all TC slip.
Oh, we did get it out wheeling the other day and it was feeling much better (I was behind him so I can only say that it sounded like the RPM's had come down). Wheeled all day and it was fine. Still too much slip, but much less than before. Appparently on the way home though the RPM's came back up. Dude sounds like he's in full race mode just to maintain 60km/h.
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09-08-2020, 12:21 AM
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Hey did you guys ever find the solution? It can, but I've verified the fluid is moving properly from trans out to trans in. Pumps real fast.
There are so many answers that almost make sense but none of them account for the fact that the thing is sitting at 30000 RPM at a light cruise, and that's all TC slip.
Oh, we did get it out wheeling the other day and it was feeling much better (I was behind him so I can only say that it sounded like the RPM's had come down). Wheeled all day and it was fine. Still too much slip, but much less than before. Appparently on the way home though the RPM's came back up. Dude sounds like he's in full race mode just to maintain 60km/h.
There are so many answers that almost make sense but none of them account for the fact that the thing is sitting at 30000 RPM at a light cruise, and that's all TC slip.
Oh, we did get it out wheeling the other day and it was feeling much better (I was behind him so I can only say that it sounded like the RPM's had come down). Wheeled all day and it was fine. Still too much slip, but much less than before. Appparently on the way home though the RPM's came back up. Dude sounds like he's in full race mode just to maintain 60km/h.
09-09-2020, 07:22 AM
#10
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