Dodge Cummins Diesel Forum banner

new tranny got really hot

872 Views 8 Replies 6 Participants Last post by  twoduners11
so i just put in a new transmission and torque converter. i dont know all the specifics about the trans as a buddy of mine builds them for a living and i left it all up to him to take care of. i do know it has a tripple disk billet converter. now heres the story- ive got about 500miles on this thing, driving down the freeway last sunday w/ the cruise on and the flexplate came apart. so when we took the trans out the fluid is burnt and the converter got so hot it turned the front cover blue! now my buddy says the stock tranny coolers are junk and i need to replace it w/ a good one (no problem) but if the last tranny lasted 50k miles slipping all the way, what could have made this thing get so dam hot in 500 miles w/o a trailer at all:confused013: i do trust my buddy im just wondering if there is something he is overlooking?
p.s. didnt have a trans temp gauge at the time
1 - 9 of 9 Posts

· Diesel Filled Veins!
Joined
·
5,772 Posts
Wrong fluid used. Must be ATF+4 not the dextron/mercon used in GM trannies. Might now be the issue but throwing it out there as a possibility. You may also have had a plugged tranny cooler (which he should have flushed out anyways as part of the job). Did he put in new tranny pump or used the old one on the cheap?
 

· Sasquatch
Joined
·
3,788 Posts
You need a transmission pressure and temperature gauge to keep an eye on things. Edit: Saw that you posted "at the time". What kind of temperatures have you been seeing?
 

· Registered
Joined
·
69 Posts
Discussion Starter · #4 ·
You need a transmission pressure and temperature gauge to keep an eye on things. Edit: Saw that you posted "at the time". What kind of temperatures have you been seeing?
truck isnt back together yet, now the company that built the converter wants it back to open up and inspect
 

· Registered
Joined
·
69 Posts
Discussion Starter · #5 ·
Wrong fluid used. Must be ATF+4 not the dextron/mercon used in GM trannies. Might now be the issue but throwing it out there as a possibility. You may also have had a plugged tranny cooler (which he should have flushed out anyways as part of the job). Did he put in new tranny pump or used the old one on the cheap?
used the correct fluid, but i know the coolers didnt get flushed out. the last tranny didnt break it just sucked from the last re-build (another shop owner owed me some money at the time)
if a cooler was really plugged wouldnt the pressure be low and the trans not shift right? this thing worked like a freight train, seriously it was like the truck got 2 more cylinders in it
 

· Premium Member
Joined
·
11,940 Posts
Correct as stated above.
Plugged, restricted, collapsed lines, or incorrectlly connected coolers will just allow to run hot with inadequate flow. Flush and prove flow on all tranny rebuilds!!!!!!!!
Some cooler circuits have a theromstat in line that can bypas cooler if not working. It will also flow when cold and plugged.
 

· Banned
Joined
·
1,322 Posts
if its a good tranny shop they'll have one of them fluid pump deals that forces the fluid into the entire trans, may have had a blockage and it didnt fill completely up, see what they say when they rip it open
 

· Registered
Joined
·
69 Posts
Discussion Starter · #9 ·
truck is all back together and picked it up tonight. new flexplate, converter, input shaft and pump now it idles rough and has a knocking. i drove it home, seems like the power is ok and the knocking doesnt get really loud when you get on it a bit its just kinda there. as far as the rough idle i would swear the balance weights fell off the flexplate but there is no balancing on them?:S:
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top