• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Blown tranny now. Honestly, what next?

Mark1972

Well-Known Member
Local time
6:14 AM
Joined
Jun 26, 2018
Messages
358
Reaction score
285
Location
Winnipeg
Do bad things happen in 3's? My goodness, what next. A month ago it was another stamped steel rocker with a pushrod through it. Now It appears I've smoked my 727TF tranny. Went for a nice 20 mile drive yesterday. Kind of a shake down run. I'd finished the roller rockers, oil and filter change, fuel filter inspection, plugs checked, and checked the timing to confirm still at 35 degrees total. All good. Come home to pick up the wife and we make it 3 blocks and then poof. The engine just died(has never happened before), so I got it in neutral immediately and pulled over. In park now, started the car, put it in drive, and it revs to about 2500 before moving. I shut it down immediately and towed it home. Oil quite dark, but the level was spot on. The tranny oil was fine just the day before. Could not get the car to move in any gear, including reverse. Park worked. Now, what to do. Tranny was rebuilt 3 years ago. Brand new 2800 stall TC was supplied as well. The had all the engine specs, as well as the dyno paperwork. In 3800 miles of driving I've maybe gone over 4500 rpm twice, and maybe spun the tires a couple times. People bug me because I drive it like an old man. I treat it very well. How could a tranny built to handle 450+hp and 500+tq give up so easily? Also, I've read if all the gears went together, it could be the torque converter. Stupid question, but how do you diagnose a bad TC?
 
That sucks man...:(

I assume you have proper kick down linkage so there is throttle pressure on the transmission kick down lever? If the torque converter grenaded then it probably sent shrapnel thorght the transmission.
 
Did seat the converter in the 2-3 click procedure as to not wipe the converter pump out correct?
 
Might be a stupid question but did you check your flex plate to converter bolts and make sure they didn’t shear off?
Lotsa aftermarket Chinese made crap out there....
 
So that tranny has been in the car since 2020, and has been absolutely fine in the 3800 miles of city/highway that it's had. To answer the questions, yes I have proper throttle/kickdown linkage, and the throttle pressure was set. Yep, I definitely followed the proper procedure for seating the torque converter when it was installed in 2020. The bolts holding the torque converter to the B&M flex plate were all still there and tight. I should have added, I've already pulled the tranny out. Finished about an hour ago. Sucks without a hoist, and I've got to have my head examined for going headers instead of exhaust manifolds, lol. But it's out. The fluid really dark, but no grit. I have not pulled the pan and filter though.
 
A good friend had a small piece of the converter brake and lodge at the cooling line outlet.
Your symptoms sound similar. See if you can freely blow through the cooling lines and radiator oil cooler.
I agree it's a bummer.
:(
 
Just another day in this FUN hobby.

:poke::lol: I feel your pain..
 
First, sorry to hear about the issues. These cars can get really frustrating when they fight us...

So I am no transmission expert - far from it. I did rebuild my first 727 earlier this year. With the way that the two drums work, it does not seem to me that your friction materials went bad. This would cause a gear to slip, but not all gears, including reverse, to stop working. So yes, maybe a torque converter or pump went bad.

I was always scared of rebuilding an automatic transmission - it seemed so complicated. I'm here to tell you that rebuilding it is really not that hard. No matter what, it sucks that your tranny took a dump, but try to rebuild it yourself. Check this thread out if it may be helpful:
Hawk's First 727 Transmission Rebuild

Good luck with the diagnosis and fix.
 
Lol, yep. You know guys, the real issue I'm facing right now is that I'm not sure I trust the shop who built it. The obvious thing to do is take it back to them and ask them what went wrong, and even though it's no longer on warranty, could they help me out because I shouldn't have to incur another $2,000+ bill for what was supposed to be a built transmission capable of handling the power the dyno numbers showed. There is another tranny place I've dealt with for years that handle my daily drivers and stuff, and I was thinking of taking it to them, but like most shops, they'll want to build one themselves instead of monkey around with another shops tranny. I've only got tomorrow off from work to lug this thing around to a shop. Or...I take it apart myself and see what I can see, take pics, and put them on the forum and see what the experienced folks say.
 
Dark oil I think it was slipping. You sure the trans pressure lever was all the way back at WOT? Maybe rebuild wasn't so hot?
 
No matter what, make sure to flush out your lines and the transmission cooler in the radiator. If you have dark fluid from slipping, the friction material debris probably stopped up your cooler. And that may have been the cause of your current problem too, if the transmission went out in the past and the system was not flushed clean. It's worth checking it out..
 
The pressure lever was all the way back at WOT. That was something that was stressed to me by the builder of the tranny. I will certainly flush those lines out. Thanks for the tip.
 
What brand convertor was it?

Was it a loose 2800? Was it slipping some cruising when you were driving it around. A slipping convertor can cook the fluid and turn it black.

727 is pretty simple...lots of help here and youtube.
Pan off usually tells a lot.
 
Last edited:
The pressure lever was all the way back at WOT. That was something that was stressed to me by the builder of the tranny. I will certainly flush those lines out. Thanks for the tip.
Make sure you flush backwards from the normal flow direction. I found the trans cooler in my Dodge pickup's 727 was stopped almost completely up! I ended up bypassing the radiator entirely and installed an aftermarket cooler big enough to be rated for an RV in front of my radiator.
 
Park worked
We all feel your pain....gotta say tho,  this is the best disguised tongue-in-cheek joke if seen in a while.

Seriously tho, lotta help here....but the Torqueflite is  tough, you are not likely to lose everything at once, unless a ring broke internally on the mainshaft, or of course the converter failed.
 
The company that built the tranny make their own convertors apparently. They chose the stall speed(2800)based on the dyno numbers and car weight, etc. So here is one of the problems. The shop that dyno'd the engine has a reputation for their dyno being a little generous. In my engines case, maybe 50hp and 50-70tq. I'll put the dyno sheet below. The car was chassis dyno'd and the rear wheels put down 345hp. Either something was slipping badly, or somehow 150hp was lost from crank to tires. That seems like a lot to me. When I gave the engine specs to two other engine builders, both said that engine, especially with my cam, would never make the power the engine dyno was reading. If the power was off, would that throw off the 2800 stall speed? I didn't know at the time that they have a not so great reputation for their torque converters.

IMG_20200523_132041.jpg
 
Btw, here are the engine specs.

440 Block bored .030"
Align bored
Decked
Factory cast-iron crank ground .010" under
New SCAT H-beam rods
Keith Black pistons(10.1-1)
Eddy RPM intake
Eddy E-Street heads (75cc chamber's)
Engine balanced
Doug's headers
CompCams XE268H cam and lifters
CompCams 1621-16 roller rockers
Melling M63 HV oil pump and pick up
Carter M6903 fuel pump
ProBillet distributor
MSD wires
440Source 6 quart oil pan, windage tray.
3.55 Yukon Duragrip 8.25
1970 Satellite (3500lbs)
 
It is also possible the convertor was slipping on the wheel dyno. The first aftermarket convertor we bought wouldn't have faired well on a wheel dyno. The 440 in front of it simply overpowered it, it likely would've held fine up in front of a small block.

For the car to basically stop moving in all gears a failed convertor is a strong possibility. I have ran into a few other things that could cause it to stop moving as well. I think it needs to be gone through again and checked out regardless.
 
Last edited:
If it turns out to be the converter, check out Dynamic Converters in DE. Frank Lupo and his team build works of art.
I have one of their 3,000 stall converters behind the 440 and it acts like a stock converter in everyday driving. I even have to hold my foot on the brake at red lights to stop the car from creeping. But power brake to 3,000 and hang on!
 
Auto Transport Service
Back
Top