trans shelled out... again

12vCumminsFTW

12vCumminsFTW

Active member
Shifted into overdrive locked at half throttle and something popped in the tranny and lost over drive. Pulled off the road and the dipstick had blown out and puked fluid everywhere? WTF? Still had 1-3 but no lockup, line pressure was all over the place and spiked to 250 once. By the time we got it limped back to the shop it was making bad noises and the fluid was completely burned up.

So any ideas? I had been hearing this weird whining noise in the trans for a while but kept driving it like a dumbass. FML
 
That "weird whining noise" was probably the pump whining because of aerated fluid running through it.
Probably sounded similar to a power steering pump that has low fluid and air has gotten into it, only the transmission has a higher pitch.

Mark.
 
LOL yeah I'm a moron. Trans is out and ill tear it apart tomorrow hopefully. Still wondering wtf would make fluid puke out the dipstick tube?

And I'm done buying used converters. This one will be sent to DPC or ill just get a new goerend.


Sent from my iPhone 4s
 
Well, found the problem I think. Overdrive brake clutches were destroyed, and the piston seal was blown out. Filter was plugged full of crap which explains the pressure going nuts.

Not enough line pressure? I was having a lockup pressure drop problem so in OD locked it was only running 160-170 max.

Also fwiw this was a 6 clutch setup with the stepped reaction plate, and the plate was warped. Maybe going to the 6 plate setup wasn't such a good idea.



Sent from my iPhone 4s
 
Mark Nixon said:
That "weird whining noise" was probably the pump whining because of aerated fluid running through it.
Probably sounded similar to a power steering pump that has low fluid and air has gotten into it, only the transmission has a higher pitch.

Mark.
Click to expand...

Truck at work with a 46re does this... How does the air get in and how do you solve the problem?

I'm still an auto trans noob...
 
I'll be the first to admit I am somewhat clueless where the internals of an auto are concerned, I prefer manuals, myself.

I'm not sure of all the ways air gets in, all I know is that when you hear that whine, it's usually because there's air in the system and it's not a good indicator.
The key is that in 99% of the installs I have done, the tranny NEVER whined and those that did whine, died 100% of the time.

Back the first time I recall hearing "that whine", many moons ago, it was because I got pissed and slammed the tranny into the converter and forced it together.
Later I found I'd cracked the pump housing and it sucked air in that way.
The car went a whole 10 miles.

Another way the pump housing gets cracked is if you DROP a tranny, like I see fools in self-serve yards do, straight from the engine to the ground, with the converter sitting on the input. :bang

During install I ALWAYS try to manually seat the tranny case to the block.
While doing so, I make sure the converter is spinning free, if it locks up before the case seats at least to the dowels, I take the tranny clear back out and make sure the converter is correctly engaged to the input and the pump drive slots.
Sometimes people think the converter is installed correctly and try to "draw" it up to the block with the bolts, then realize they need to finish seating the converter and many times it's already too late.

I've had trannies, especially ones with NEW converters, where you had to stand them on end to get the torque converter to fully engage the pump drive slots!
Pretty rare and unnerving.

Mark.
 
Could a dirty filter cause the whine? I noticed when the pressure was dropping the whine got really loud and when I dropped the pan the filter was completely clogged up. Pump has some slight scoring as well.
 
First off, What fluid were you using? Yes a dirty filter would starve the pump and cause the whine. Then with the 6 Od Brake Clutchs; Did you run one snap ring( flat not wavy) then the plate then clutches and steels then the wire lock ring? Then the Od piston did you measure the od depth to determine the correct spacer and shims to make the torrent bearing ride with out excessive pressure? I just finished up one yeterday that had a .235 shim when it called for a ~.185. They looked pretty toasty when i took it apart.
 
I was running some transtar stuff that the local trans builder gave me, I ran plain old dex/merc before that. Yes just the flat snap ring. Not sure on the clearance, the trans guy put that all together.

I'm more concerned about the stepped reaction plate being bent. It was pretty toasty in there but not sure if it warped from heat or just pressure. it is pretty weak looking compared to the stock/ 5 plate setup.
 
You can make the step a little thicker and still get the clearance you need. I think a 48 plate is .120 and I have them machined .140 out of a stock 47 plate. Either way the heat is what killed the plate, not anything else so if you can keep it from slipping you should be fine. I run 6 clutches and don't have a problem.

How long ago was the Trans rebuilt with new seals? It's very easy to get a nick in the seals and cause the clutches to burn up.

Also, what kind of clutches are you using?
 
Sounds like the OD piston hung up on the retainer, the check ball on the od piston support could be stuck too from excessive pressure or improper shim of the OD. If you're so worried about the plate its only $25 give or take.
 
mathews8pt said:
You can make the step a little thicker and still get the clearance you need. I think a 48 plate is .120 and I have them machined .140 out of a stock 47 plate. Either way the heat is what killed the plate, not anything else so if you can keep it from slipping you should be fine. I run 6 clutches and don't have a problem.

How long ago was the Trans rebuilt with new seals? It's very easy to get a nick in the seals and cause the clutches to burn up.

Also, what kind of clutches are you using?
Click to expand...

Trans was rebuilt back in june but the truck was down for a while so it really only has a few weeks of runtime on it. I believe we used the clutches from a Suncoast kit, raybestos frictions and those kolene coated steels.

How much line pressure are you running? I was having a pressure issue and was only getting 150-160 psi in OD locked over 2000 rpm. Under 2000 rpm the pressure dropped fast. I had noticed since the rebuild the 3-4 shift was kinda slushy, was probably slipping from day 1.

I found this post from bigblue24.
Competition Diesel.Com - Bringing The BEST Together - View Single Post - OD brake clutches burnt

I want to get the pressure up to at least 180-190 in OD locked, should help it last.
 
I don't think your pressure is a big problem, although a little more will help. I ran ~140psi for a couple years and up to ~675hp with a big single charger. Never had problems burning up OD and it was my DD back then so lots of miles. Now it's around 170-180psi.

If its got that low of miles I think it had to be a cut seal or incorrectly chosen spacer.

Clean the piston and retainer with scotchbrite pad until all the little nicks are gone as well.
 
I'll tear the rest of it apart this week, hopefully nothing else is hurt. I'm tempted to rebuild it myself this time, hell the first build I did myself lasted longer than when I paid someone to do it.:doh:
 
if that piston seal tore, it may have smoked the clutches leading to a plugged filter.

its not the packs fault if it was set up properly.
 
ahale2772 said:
if that piston seal tore, it may have smoked the clutches leading to a plugged filter.

its not the packs fault if it was set up properly.
Click to expand...

I agree, if the seal had a little cut in it from being installed wrong it would get that "mushy" feeling going into OD since the pressure is being bled off, and eventually the seal would blow out and hang the piston in the applied position and burning your clutches even faster, or what's left of them. LOL

That might also explain your pressure drop shifting to OD, if the OD piston seal was torn from the get go.
 
Just to be clear here, I was not getting a line pressure drop going into OD. It only dropped pressure when locking the converter, in any gear. I guess I should really have checked pressure at the OD port, might have told me something there.


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