workingdog
GOLD Star
This is a 4L60 behind a 5.3l vortec with a magnason supercharger in an 84 FJ60. I've blown the 4L60 twice in this truck in less than 10,000 and I'm not sure why - and that's without putting my foot in it very hard (i'm scared to death of the truck now). So this time, after spending thousands on my 3rd heavily built tranny, I'm trying to figure out what's going on. It's fine around town, but it always acts up on longer drives. So I took it to the Sierras over the weekend to see what happened and it did something it's done in the past which I think is related.
3/4's of the way to Donner Summit from Auburn (where the climb starts) or about 45 minutes in the hill (and 2 1/2 hours into the drive - it seems to take some time for this to happen), I'm on one of the longer sustained climbs, the OBDii gauge says I'm putting out about 110 to 120 hp and about 300 foot pounds of torque (just about 0 on the boost gauge), near the top (and Cisco Grove) the transmissions seems to unlock. I used to think this was a downshift, but this time I'm pretty sure it was the torque converter unlocking (based on the rpm change and rpm behavior on and off the gas). And just like last time, it didn't lock back up at the top of the hill, in fact, uphill, downhill, it didn't matter, it stayed in that mode. About 10 minutes later, as I'm pulling the final bit before the summit, I experience a 'clunk' and it locks back up and it's fine from then on.
Does anyone understand this behavior? I can't find anything that might explain it online.
I can't use my OBDii to read tranny temp, so the temp stored in the PCM/TCM is useless to me, so I'm putting a mechanical temp gauge this week and I'm going to have them install an additional tranny cooler as well.
3/4's of the way to Donner Summit from Auburn (where the climb starts) or about 45 minutes in the hill (and 2 1/2 hours into the drive - it seems to take some time for this to happen), I'm on one of the longer sustained climbs, the OBDii gauge says I'm putting out about 110 to 120 hp and about 300 foot pounds of torque (just about 0 on the boost gauge), near the top (and Cisco Grove) the transmissions seems to unlock. I used to think this was a downshift, but this time I'm pretty sure it was the torque converter unlocking (based on the rpm change and rpm behavior on and off the gas). And just like last time, it didn't lock back up at the top of the hill, in fact, uphill, downhill, it didn't matter, it stayed in that mode. About 10 minutes later, as I'm pulling the final bit before the summit, I experience a 'clunk' and it locks back up and it's fine from then on.
Does anyone understand this behavior? I can't find anything that might explain it online.
I can't use my OBDii to read tranny temp, so the temp stored in the PCM/TCM is useless to me, so I'm putting a mechanical temp gauge this week and I'm going to have them install an additional tranny cooler as well.