48re temps/maintenance
 

Time for trans service. I have about 55k on rebuild, fluid is dark but does not smell burnt. I'm taking it in later this week to a reputable shop who is going to drop the pan and put new filter in. I asked them if they did a band adjustment as well while they were in there and they said they would adjust what was external as needed. This is my first rodeo with trans maintenance besides changing the return line (how I know fluid is dark). Is there anything specific to tell them/look for? My truck shifts fine, it has been getting warm according to my gauge (EJWA). Daily driving empty usually runs 180-200 Texas temps 70-90 degrees. Will a basic fluid change "exterior adjust" and filter cool me down? It seems I should be in the 150 temp range empty with the mixed driving I do. The guy I spoke with said doing that maintenance every 50k will make that trans last a lifetime without extreme circumstances- any help is appreciated!

Those temps are high for an empty truck! What TQ are you running? Stock would probably be the reason! Slipping TQ really heats up the fluid!

Everything is stock from the rebuild -prior owner had paperwork and I spoke with the shop to confirm work. The torque converter could be slipping that bad even from being rebuilt pretty recently? Is that something I can check or they would be able to get to during routine maintenance to see if something ain't right? Also wouldn't it not be shifting well if that was slipping?

Been doin more research- I realize this can be a large can of worms to open but anyone have thoughts on bypassing heat exchanger? I'm down in TX so cold temps aren't an issue most days. Seems this could help but seems long term may be a hindrance! Anyone done this and liking it?

Don't do it! If you tow anything or get into the hundreds there leave it alone! Truck will shift fine with a slipping TQ. Just fluid will get burnt "Dark" and temps will be higher than normal! Find out if they put a TQ in on the rebuild! A single more than likely "Junk"!

Those are normal temps and where the trans is designed to run. Anything between 140 and 240 degrees is operating range, 180-200 is perfectly normal in higher ambient temps as long as it cools back down under 200 when the TC locks and you are moving down the road.

Yes, given you are that far south you could bypass the heat exchanger and add an aux cooler that is thermo controlled. That will cool your cruising temps down but probably not much for stop and go where the TC never locks, may even be worse when the temps get into the triples. You MUST add the aux cooler though or it will get really hot. The aux cooler has its own problems with install and setup, truthfully unless you are towing heavy in slow going it can be more of a problem that a solution.

At 55k your are 20k past the recommend change interval, probably why the fluid is darker than normal. Every 30k is about what the fluid is designed to run and keep its additives functional. When the fluid gets dark it is loosing additives and picking up more contaminats.

Thanks for the info- Cerberus- I think I saw you on the long 30 page trans convo on Cummins forum. I'm gonna change fluid, remove check ball, and remove/clean stat for peace of mind. I've read people putting them in backward for constant cooling but don't think I need that mod for my limited towing. Heat exchanger will stay hooked up for now. Once i can part with my boat I'll get a trans but till then gotta take it easy :dang: - I will get on track with the pan drop and that should keep me ahead of the curve for now

While I have y'alls attention There's a member on here selling trans parts at great prices- he recommend to install 47re triple disk on the 48re- it's supposed to work well but does not have a seal the 48re has which is not an issue? I asked my buddy who builds trucks and hasnt heard of this have y'all? Obviously want to save a buck if possible but not at the expense of sitting on the side of the road because my truck won't move!

Removing the drain back check ball will help, adding a shift kit will help some more and keep the trans a lot happier.

A 47RE TC will fit but there is really no reason for it. The missing seal is for drain back, no big deal. A good single disk TC for a 48RE will be all you need unless you tow way heavy or want to compete with big power.

That's good to know- I'm hoping to have about 600-700hp all said done but built trans isn't in the budget right yet- I may pull the trigger on that tc and start piecing together my rebuild. I'll keep my low hp tunes running with my stocker and valve mod just want to keep it happy during the summer coming up! Thanks:tu:

Dropped the pan and replaced it with a standard B&D with drain plug to prevent mess down the road. Temps have dropped 10-15 degrees cruising and cools off quickly relative to before. I'll be pulling check ball tomorrow and draining pan again here in another month or so- I'm interested to see how much the check ball helps :humm: