UMMmm
Unless you blow a driveline, axle or ring and pinion. If that day ever happen to me. My trans will not go back under power until its torn down to check for damage. i value my legs
727 or 904?
- Thread starter Magster65
- Start date
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UMMmm
Unless you blow a driveline, axle or ring and pinion. If that day ever happen to me. My trans will not go back under power until its torn down to check for damage. i value my legs
Then make sure all those things are right. If it's a serious race piece, sure have all of the right stuff in place. A street car will rarely "blow" a driveline, as long as it's not a 7.25.
There are people that don't give a **** about there ride. u-joint wear out rear end seal go bad. But YES, yes yes drum explosions are rare in stocks street set up. and yes when i have my 727 rebuild, i will invest in a better drum.
Duane
Well-Known Member
I have a friend at my local track who runs a 904 with a griner brake without low band apply. Car does wicked wheelies on launch.
He always does his burnout in Second gear just like is advised.
He broke the sprague this summer. By his own diagnosis it failed from losing and regaining traction on a slippery track while still in first gear. If that happened to a 727 it would over speed the drum and explode.
Talk to Paul Forte at Turbo action or John Cope and they will tell you the same thing. You only have to see these explosions once to know that it is not worth the risk. You need an aftermarket drum and a better sprague to be safe. You cannot control track conditions.
The major trans builders will never advise you to start your burnout in first with a torqueflite. People do it and get away with it, but it is not advised. Second or third only. Low band apply. IMHO.
about 15 yrs ago I broke a ring gear in a 8 3/4 with a 904 trans. Never torn the trans apart..replaced the R&P....made 6 more passes on the car with a transbrake before I figured the sprag was bad......
I don't have to talk to anybody, thanks, though. I know full well about their shortcomings. What I am talking about is for mild use, such as a street car, the 727 is fine.
Did you see me talking about wheelies?
Did you see me talking about wheelies?
340, 4.56 gears and only a 2500 stall will not do a burnout of the water box with out starting in 1st! But like rusty said, start in 1st shifting immediately into 2nt before burning out of the water box edge.
My 408 has no problem with starting out in 2nt gear with same converter.
My 408 has no problem with starting out in 2nt gear with same converter.
Duane
Well-Known Member
Yes it is located there. But he said his throttle valve was not adjusted correctly. If that were the case the pressure may have been not enough for how far his foot was into the throttle. Regardless of the base line pressure setting the pressure is modulated by the throttle valve. How could he fail 3 second gear bands in a row.? Imho
Duane
Well-Known Member
A street car probably spins his tires more than a drag car goofing off.
I know I used to love doing those bunny hops as we called them back in the day when I did not know any better.
I agree, but how many transmission explosions have you ever known about on the street before everybody became an internet expert?
72Dart6pack
Harder Better Faster Stronger.
Doing my 904 this week.
j par
Well-hung Member
A clogged vein in the valve body or partially? Maybe a bad piston wall in one of the servos? Not holding a band tight? Not sure how that works I'm not like a transmission Guru, just spitballing.
Duane
Well-Known Member
I cannot say that I have ever seen an explosion on the street. But I can tell you that the 3-4 that I have seen at the drag strip were street/strip cars in the 13-14 second et range. These cars perhaps are being abused on the street and were at the track when the sprague finally gave up. But that is speculation on my part.
It would have lived if i left it in drive because......there is only a 2nt gear engage(no timeing or speed of band required) first gear is a clutch, 2nt is first gear clutch and 2nt gear band. IN LOW 1 there is first gear (clutch) applied and reverse band applied(only in low 1) if there was no binding between reverse band and 2nt band, transmission would have lived forever. Manual shift valve body has lasted for over 25 years.
2nt gear Band did not dye from slow or slipping in to 2nt gear, it was the binding of reverse and 2nt bands(one trying to release and the other trying to apply) ...........kind a like bumping the trans brake momentarily while shifting into 2nt. no i don't have a trans brake, but do you get it now?
j par
Well-hung Member
Thank you for posting the picture. I've been having thoughts of going out in the shed and grabbing all the pieces of the 904 I have back there and just putting it together in about 7 pictures. I mean really it's just a pile-o-parts, there isn't anywhere a part can go that it shouldn't it's almost foolproof.
Duane
Well-Known Member
You have completely missed what I said about the traction issue.
That is another way that the sprague can fail. The tires grip, ungrip and then regrip again.This can shock the sprague and fail it. Nothing to do with the burnout. That is why some trans brake makers believe you should have low band apply to protect the sprague.
j par
Well-hung Member
Seems like there could be a wide variety of problems of anything it could ha e been? I mean if there was an accidental too much play in the clutch pack or maybe the clutch piston had a cut seal or the Piston wall had to score in it letting some pressure out and not engaging the clutches as tight as they should be or a week return spring?
this was not for you it was for rusty and his coment about starting is 2nt gear. With my 340 I could NOT start in 2nt gear.
I agree that a slip and grip could fail a sprag if it happen in 1 gear launch. not arguing here.
Duane
Well-Known Member
Why were you shifting it that way after 3 band failures lol
Duane
Well-Known Member
My apologies then. Just trying to help.
j par
Well-hung Member
When I ponder on that 904 I think to myself... Is there any way possible any part would fit in the wrong spot? I mean could someone take a 904 and put it 100% back together using all the parts and it be wrong? I mean you can extremely easily air check most your new seals before you even load it in the housing and you can do it then again before you put the vb in? I guess you could do something colossally stupid like put two clutch disc's and two steels together by accident, but no one is that stupid. Non of the servos (3) would fit correctly if each one didn't have all its parts? Am I not living proof that rebuilding a 904 is near foolproof? Not absolutely one special tool required at all. Unless of course a piece of angle iron cut to put in your Vice to take out the clutch pack spring but that's the easiest redneck tool I ever made. Oh yeah I have that whole I need a big massive clean area to do this all on? I found that a 2 foot by 8 foot sheet of plywood with a couple stools under either end was way more room than needed. You have absolutely nothing to lose by opening up a 904. If you don't get all the parts back together and you take it to professional and he can't figure out where things go than you've got the wrong guy definitely. All this comes up when I think about that completely disassembled 904 in my shed again and I think is there a possible way I could bring that all out and put it together wrong? I don't think so.....
j par
Well-hung Member
Oh yeah I remember being all hung up on tolerances and all that. That turned out to be kind of a joke when I ask someone who really knows his trannies and races them quite often the answer was I don't remember ever checking LOL
Of course on the videos to do so you got to connect this special micrometer to the outer shell that reaches way over and touches the input shaft LOL of course a great member here sent me a video on rebuilding 727 and it showed just this very simple way of clamping a vice grip on the input shaft after it's pushed in and then pulling out on it and put a feeler gauge behind it and see how far it's came away from the outer pump shaft. I've been told by a few transmission gurus that Mopar Transmissions like to be a little loose anyways.
Of course on the videos to do so you got to connect this special micrometer to the outer shell that reaches way over and touches the input shaft LOL of course a great member here sent me a video on rebuilding 727 and it showed just this very simple way of clamping a vice grip on the input shaft after it's pushed in and then pulling out on it and put a feeler gauge behind it and see how far it's came away from the outer pump shaft. I've been told by a few transmission gurus that Mopar Transmissions like to be a little loose anyways.
j par
Well-hung Member
Still scratching my head here only two bands neither one would fit where the other one goes and neither one would fit going in backwards?
j par
Well-hung Member
Short of dropping a junior mint in while in surgery I don't see what could go wrong?
Kramer
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