heavy towing with auto trans?
 

My truck has the 48re trans and I come in at 18k and up (gross) on a regular basis and the truck just does not want to pull hills at all. Even just getting going seems like a process from a dead stop. If I come out of a dead stop and hit even a small grade for a short distance (1/2 mile or so) the truck just does not want to accelerate. I know that someone did work on this trans in the past (BD trans pan), aftermarket in line trans filter, not sure what was done on the inside. I got no paper work when I bought the truck with 116k on it. Should I expect more out of this trans????

yes you should. I'm not the tranny expert but it sounds like some major slippage and a tranny rebuild is in order.

Check out Goerends HD rebuild on the website. It's one of the best going and the price is reasonable.

Something is amiss.

My toy hauler is over 16k lbs...truck pulls grades nicely with the 4.56's I've got.
Tranny is bone stock with nearly 110k miles on it.

I pull 18k loads of hay kind of regularly, however I am never starting out on a hill. It pulls real nice once tc lockup has occurred.

Definitely take it easy accelerating uphill with a heavy load, until the torque converter locks. Things can heat up in a hurry otherwise.

I was thinking about doing the torque converter lockup mod for that reason.

If it was my truck I would have egt and trans temp gauges before towing heavy. Locking the TC prematurly will cause EGT to go through the ceiling....

This is the first I heard of the TC lockup mod making the EGTs rise. Definitely something to keep in mind. I've wanted a set of gauges for a while now, just hesitant on which ones to buy. Trans temp gauge will help me determine if the trans is slipping, correct? Quick rise is temperature means its slipping while pulling???

A rise in engine RPM without a corresponding speed increase(or downshift) indicates a slipping tranny.

could this be as simple as just having bands adjusted? I don't have any prior service records for the truck so I don't know what was done up to roughly 120k miles and its now pushing 150k.

well today I dropped the pan and serviced the trans and adjusted the front band. I replaced the inline filter that was put in also for the trans. while in there I saw that it looks like the previous owner put in a bd diesel valve body. I have a bd intake horn and exhaust manifold on the way. I put a triple pillar gauge pod in and plumbed everything for boost, pyro and trans temp. trans temp on the way home was between 150-160 whether cruising or stopping or accelerating.

If you have the stock crappy TC the fluid coupling is terrible towing heavy. That is the main reason I went through my tranny. I pull at the same weights. Step on the go pedal and you would never know how fast you may or may not go. With my Goerend tranny upgrades, I have no issue. I have a 15 blade left cut TC. It is awesome.

I've always felt that there was an aftermarket tc in the truck. Just sucks because I will never know until I drop the transmission to find out for 100% sure. But if I drop the trans a nv5600 will most likely go back up in its place.

If there isn't room to get the speed to lock the tq converter it won't pull a hill unless your in 4 low with weight. 06 and 07 with 5.9 and 07.5 with 6.7 all the same. Add weight and a hill in a neighborhood somewhere with weight and your waiting for 4L to kick in. Got the 06s tranny built by sun coast and fixed that crap. I have literally towed gross 33k up a hill and the tires will light up now.