4L60e trans have a 375HP 383e stroker installed 25k miles ago do a LOT of towing, almost exclusively used to tow with. while the trans is out, replaced the trans front seal, even though there were no leaks. Engine rear main seal is fine. Torque converter looks fine, old trans fluid looked/smelled a little burnt, but not bad and was due for a change anyway Thinking of replacing the TC with a low stall unit, just on GP. Or should I just throw the old one back in?
I'd stay with stock. Unless that trans has had some work it is likely borderline with that engine. Don't want even more torque through it.
If that trans has not been apart, I'd be tempted to open it up and do all the recommended upgrades to it now. Like a better sun shell, bore and sleeve the valve body, replace the clutches and steels. Of course if that was already done, don't bother. As for the flex plate, use a HD aftermarket unit and check the trans alignment close.
Turns out the flexplate was completely broke at the center hub. It also shows signs that it had been damaged for a long time. Multiple cracks and some bent parts.
The good news is that the torque converter is fine and is a low stall speed unit, 1397rpm stall. It also had zero sign of damage and looks like a new one. Fluid was just slightly dark and with a very slight smoky smell, but nothing serious. Took the old trans filter out and cut it apart to find... nothing. No metal shavings, no dirt, not even dirty. Put in a new filter and after completely allowing the converter to drain out, put in 11 quarts of new fluid and reassembled the parts and with a few tries at properly shimming the starter, it starts, shifts and runs like new. Also replaced the trans front seal, which was a real bitch to take out but went back in like a hot knife through butter.
Next on the agenda is to drain and refill the transfer case, but there wasn't enough time to do it today. Next week. Also going to put in an aftermarket trans fluid cooler. Every little bit a lower heat helps, right? Maybe a trans fluid temp guage too.
Thanks to everyone who offered advice. This group rocks.
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