Page 1 of 3 123 LastLast
Results 1 to 20 of 41

Thread: I cracked my 31TH trans case

  1. #1
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    I cracked my 31TH trans case

    I welded a gusset to support the pinion shaft but all I did was move the stress point down. I'll have a gusset welded on both sides of the crack on my new one but I think I'm going to retire the van from racing. 13.3 is brag-able and I won't have to keep fixing it.


  2. #2
    Supporting Member II Turbo Mopar Contributor
    Join Date
    Dec 2005
    Location
    Sylmar, CA
    Posts
    2,584

    Re: I cracked my 31TH trans case

    Bummer, sometimes there's just no getting around the limits of the parts.

    Back when, I built a SR500 hot rod single cylinder motorcycle - piston, cam, pipe with reverse cone megaphone. She made great power with RPM.

    Syncing the megaphone dimensions to the head pipe length to the cam centerline to the intake length - that's where the magic was.

    Cracked, parallel to the deck, below the deck, on two blocks.
    Cracked, parallel to the deck, above the deck, at the base of the cylinder, two more.

    The fifth time, she got parked. Over the last 20 years, I've collected some more engines/cases/cylinders to crack . . . . . someday.
    John Laing

    "The sole condition which is required in order to succeed in centralizing the supreme power in a democratic community, is to love equality, or to get men to believe you love it. Thus the science of despotism, which was once so complex is simplified, and reduced . . . . to a single principle."
    -- Alexis de Tocqueville

    "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary."
    --Ayn Rand

    "To evolve, you don't need a Constitution. All you need is a legislature and a ballot box . . . . things will evolve as much as you want. All of these changes can come about democratically; you don't need a Constitution to do that and it's not the function of a Constitution to do that."
    -- Justice Antonin Scalia

  3. #3
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    Re: I cracked my 31TH trans case

    Quote Originally Posted by johnl View Post
    Bummer, sometimes there's just no getting around the limits of the parts.
    A guy in the shop next to me said, "Drive it like a race car, work on it like a race car."

    I'm thankful I found it. My lock up torque converter lost lock up so I had to pull the trans. I pulled the front pump to inspect the input shaft and seals to see if that's why lock up failed. I couldn't find anything and sent the converter in. The lock up seal in the converter failed. I pulled the paper gasket to put on a new one and found the crack. It could have been worse. The pinion could have ripped out of the case and taken out my $1100 LSD. I have a new case. I have two out of three gussets made. I'll post pictures of my new supports when I get them welded in. I really want to crack 12's.

  4. #4
    boostaholic
    Join Date
    Oct 2007
    Location
    Stanton, DE
    Posts
    1,026

    Re: I cracked my 31TH trans case

    That sucks, but nice job on the welding.

  5. #5
    Super Moderator Turbo Mopar Staff contraption22's Avatar
    Join Date
    Dec 2005
    Location
    Havertown, PA
    Posts
    9,517

    Re: I cracked my 31TH trans case

    I had that happen. I chalked it to brake boosting too hard with a leggy turbo. Once I started using nitrous, I stopped breaking transmissions.
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
    Project Log:
    http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=

  6. #6
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    Re: I cracked my 31TH trans case

    Quote Originally Posted by contraption22 View Post
    I had that happen. I chalked it to brake boosting too hard with a leggy turbo. Once I started using nitrous, I stopped breaking transmissions.
    Automatic or manual? And can you explain why lag and you think adding nitrous stopped it from happing? I recently switched to a 1.0 turbine housing from a .75 because the .75 spooled too quick and now the 1.0 is a touch too laggy. I don't know how long the crack has been there. I think I might end up going back to the .75 because at least with it I could feather the gas and get the power when I want it. With the 1.0 there is 5 lbs right away, a pause, and then 15 lbs hits like a freight train.

  7. #7
    Super Moderator Turbo Mopar Staff contraption22's Avatar
    Join Date
    Dec 2005
    Location
    Havertown, PA
    Posts
    9,517

    Re: I cracked my 31TH trans case

    With the laggy turbo I was brake boosting on the line for 10-15 seconds to try to build boost against the torque converter. That's a lot of torque against a pinion shaft that cannot turn, prying against the trans case.
    Nitrous allowed me to spool the turbo almost instantly, so brake boosting wasn't needed anymore.
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
    Project Log:
    http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=

  8. #8
    Supporting Member Turbo Mopar Contributor zin's Avatar
    Join Date
    May 2006
    Location
    ca
    Posts
    4,479

    Re: I cracked my 31TH trans case

    Sounds like a trans-brake would fix it too, though not nearly as fun as nitrous!

    Mike
    "The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry

    Bad laws are the worst sort of tyranny.
    - Edmund Burke

  9. #9
    Supporting Member II Turbo Mopar Contributor
    Join Date
    Dec 2005
    Location
    Sylmar, CA
    Posts
    2,584

    Re: I cracked my 31TH trans case

    There must be a Mil Spec inspection shop near you - Zyglo to find any pre-existing flaws, then weld, and then shot peen to stress relieve both the weld area and the rest of the case generally.
    John Laing

    "The sole condition which is required in order to succeed in centralizing the supreme power in a democratic community, is to love equality, or to get men to believe you love it. Thus the science of despotism, which was once so complex is simplified, and reduced . . . . to a single principle."
    -- Alexis de Tocqueville

    "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary."
    --Ayn Rand

    "To evolve, you don't need a Constitution. All you need is a legislature and a ballot box . . . . things will evolve as much as you want. All of these changes can come about democratically; you don't need a Constitution to do that and it's not the function of a Constitution to do that."
    -- Justice Antonin Scalia

  10. #10
    Supporting Member Turbo Mopar Contributor turbo84voyager's Avatar
    Join Date
    Jul 2008
    Location
    Nanticoke PA
    Posts
    805

    Re: I cracked my 31TH trans case

    Seems like brake boosting causes most of the failures of the "Hard parts" of these transmissions. I cannot imagine the stress on the case and even the input shaft and transfer shaft. I'm sure the LSD ( which is much better than the open diff) does not help out the situation because your hooking up better and all of the stress has to go somewhere. Wonder if anyone has ever tried to do a trans brake on these?
    Justin
    84 Plymouth Voyager LE 2.5 Intercooled Turbo 5-spd - Only 84 Turbo Van!
    89 Dodge Caravan ES 2.4 SRT-4 Intercooled Turbo (46 trim, OS Valves, CP Pistons, Eagle Rods, NPR IC) Built 31th trans
    91 Dodge Shadow Convertible 2.5 Intercooled Turbo A555 5-spd
    01 Pontiac Grand Prix GTP - 3.8 supercharged! Only 5K miles....
    01 Subaru Forester - Daily Driver
    07 Yamaha FJR 1300 140+ HP on 2 wheels
    85 Honda Nighthawk 450
    94 Bobcat 763 Skidloader 2.2 Kubota Diesel
    SV-SDAC Member

  11. #11
    Supporting Member Turbo Mopar Contributor GLHS60's Avatar
    Join Date
    Dec 2005
    Location
    Sherwood Park Alberta, Canada
    Posts
    1,640

    Re: I cracked my 31TH trans case

    I sure hope you have better luck with the 32ND trans.

    Thanks
    Randy


    There is no logical reason to call an Engine a motor.

    Randy Hicks
    86 GLHS60
    86 GLHS 373 : SOLD, but never forgotten
    89 Turbo Minivan
    83 Turbo Rampage : SOLD
    Edmonton,Alberta,Canada

  12. #12
    Supporting Member Turbo Mopar Contributor turbo84voyager's Avatar
    Join Date
    Jul 2008
    Location
    Nanticoke PA
    Posts
    805

    Re: I cracked my 31TH trans case

    How many people have cracked their cases? I never remember hearing much about cracked cases till recently. Most of the ones in the past were caused by a failure of something else.
    Justin
    84 Plymouth Voyager LE 2.5 Intercooled Turbo 5-spd - Only 84 Turbo Van!
    89 Dodge Caravan ES 2.4 SRT-4 Intercooled Turbo (46 trim, OS Valves, CP Pistons, Eagle Rods, NPR IC) Built 31th trans
    91 Dodge Shadow Convertible 2.5 Intercooled Turbo A555 5-spd
    01 Pontiac Grand Prix GTP - 3.8 supercharged! Only 5K miles....
    01 Subaru Forester - Daily Driver
    07 Yamaha FJR 1300 140+ HP on 2 wheels
    85 Honda Nighthawk 450
    94 Bobcat 763 Skidloader 2.2 Kubota Diesel
    SV-SDAC Member

  13. #13
    Moderator Turbo Mopar Staff Vigo's Avatar
    Join Date
    Feb 2006
    Location
    San Antonio,TX
    Posts
    10,798

    Re: I cracked my 31TH trans case

    I sure hope you have better luck with the 32ND trans.
    Bwahahaha.

    How many people have cracked their cases? I never remember hearing much about cracked cases till recently. Most of the ones in the past were caused by a failure of something else.
    Pretty much only people who brake boost 15+psi right into the peak torque zone on 2.4s and 2.5s. At least that's what it seems like. People have probably been breaking them for longer than the internet was around to talk about it.

    Dont push the red button.You hear me?

  14. #14
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    Re: I cracked my 31TH trans case

    Quote Originally Posted by Vigo View Post
    Pretty much only people who brake boost 15+psi right into the peak torque zone on 2.4s and 2.5s. At least that's what it seems like. People have probably been breaking them for longer than the internet was around to talk about it.
    So is it a general consensus that it's the brake boosting that's the problem? I've researched this transmission and didn't see any case failures. On the SRT-4 forums they have failures with the $9000 DCR transmission but the owners don't do their own work on the transmissions and DCR doesn't announce what their failures are. I might have to consider going the nitrous route just for the track when I launch.

  15. #15
    Moderator Turbo Mopar Staff Vigo's Avatar
    Join Date
    Feb 2006
    Location
    San Antonio,TX
    Posts
    10,798

    Re: I cracked my 31TH trans case

    Thats the conclusion i came to a long time ago when ohiorob had a thread tossing around the idea of fitting a gm 4t60 after he blew up his case on the line. There was an incar vid linked of stephanes old 8 second charger and from what i was able to tell he was actually launching on 5-10psi which isnt a hell of a lot of torque on a 2.0-2.2.

    There was another thread here on tm recently where one of the guys who works on red sled was talking about all their trans mods and saying theyve got to a point where they feel its pretty reliable under 8 second 1/4 conditions.

    Sorry i dont have links to either of those threads handy.

    If you're still running tm electronics you could consider using anti-lag to lessen torque while still building boost, and theoretically when you let off the brake or whatever youve got it triggering from, all the torque is there as the timing reverts to normal.

    Dont push the red button.You hear me?

  16. #16
    turbo addict Turbo Mopar Contributor
    Join Date
    Dec 2005
    Location
    Seattle
    Posts
    7,063

    Re: I cracked my 31TH trans case

    Quote Originally Posted by Vigo View Post
    Thats the conclusion i came to a long time ago when ohiorob had a thread tossing around the idea of fitting a gm 4t60 after he blew up his case on the line. There was an incar vid linked of stephanes old 8 second charger and from what i was able to tell he was actually launching on 5-10psi which isnt a hell of a lot of torque on a 2.0-2.2.

    There was another thread here on tm recently where one of the guys who works on red sled was talking about all their trans mods and saying theyve got to a point where they feel its pretty reliable under 8 second 1/4 conditions.

    Sorry i dont have links to either of those threads handy.

    If you're still running tm electronics you could consider using anti-lag to lessen torque while still building boost, and theoretically when you let off the brake or whatever youve got it triggering from, all the torque is there as the timing reverts to normal.
    2 step on an auto is a smart idea because you can build boost without the rpms going up (putting even more load on the transmission) and as said, the retarded ignition timing kills power. In this situation you are building boost thanks to poor combustion instead of full WOT combustion. I think I would also not let boost get too high for the actual moment of launch. I know some guys with auto transmissions (powerglides etc on RWD small engine turbo cars) hit the spray right before launching to flash their converters up but I would not want to do that with the problems that are being reported.

    Red Sled has made a lot of passes that are much slower then it has gone in the past and I feel that regarding what Vigo says, this is part of a very careful boost/launch control setup that is intended to protect the transmission while still launching well. I think there have been a lot of difficulties getting things right. I think the best time for that car is still on spray and a tired old motor, meaning making HP is not the problem.
    Brent GREAT DEPRESSION RACING 1992 Duster 3.0T The Junkyard - MS II, OEM 10:1 -[I] Old - 11.5@125 22psi $90 [U]Stock[/U] 3.0 Junk Motor - 1 bar MAP [/I] 1994 Spirit 3.0T - 11.5@120 20 psi - Daily :eyebrows: Holset He351 -FT600 - 393whp 457ft/lb @18psi 1994 Spirit 3.0T a670 - He341, stock fuel, BEGI. Wife's into kid's project. 1990 Lebaron Coupe 2.2 TI/II non IC, a413 1990 Spirit 3.0 E.S. 41TE -- 1993 Spirit 3.0 E.S. 41TE -- 1994 Duster 3.0 A543 1981 Starlet KP61 Potential driver -- 1981 Starlet KP61 Parts -- 1983 Starlet KP61 Drag 2005 Durango Hemi Limited -- 1998 Dodge 12v 47re. AFC mods, No plate, Mack plug, Boost elbow -- 2011 Dodge 6.7 G56

  17. #17
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    Re: I cracked my 31TH trans case

    I got the original gussets and one more welded into a new 31TH case.




  18. #18
    Moderator Turbo Mopar Staff Vigo's Avatar
    Join Date
    Feb 2006
    Location
    San Antonio,TX
    Posts
    10,798

    Re: I cracked my 31TH trans case

    It's a thing of beauty!

    Dont push the red button.You hear me?

  19. #19
    Supporting Member II Turbo Mopar Contributor DOHCRT's Avatar
    Join Date
    Dec 2005
    Location
    Phoenix, Az
    Posts
    512

    Re: I cracked my 31TH trans case

    AJ, Are you stress relieving the case after all of that welding? Some simple stress relief will probably help with the longevity of the case. All of those welds are adding a ton of concentrated stresses into the case that should be reduced\removed.


    Vic in Phoenix
    dohcrt@cox.net

    91 Spirit R/T x4
    92 Spirit R/T x2
    89 CSX
    88 CSX-TIII
    84 Rampage TII
    97 Ram (Buzzin Half Dozen)
    69 Dart GT 'Vert

  20. #20
    Supporting Member II Turbo Mopar Contributor A.J.'s Avatar
    Join Date
    Feb 2006
    Location
    Mesa, AZ
    Posts
    2,427

    Re: I cracked my 31TH trans case

    Quote Originally Posted by DOHCRT View Post
    AJ, Are you stress relieving the case after all of that welding? Some simple stress relief will probably help with the longevity of the case. All of those welds are adding a ton of concentrated stresses into the case that should be reduced\removed.
    What's stress relieving and how do I do it?

Page 1 of 3 123 LastLast

Similar Threads

  1. Internal parts from 525 trans/no case
    By jeff1234 in forum General Vendor Area
    Replies: 5
    Last Post: 05-30-2012, 08:53 AM
  2. Transmission WTB: A-543 3.0 V6 trans case or rebuildable trans
    By Force Fed Mopar in forum Parts Wanted
    Replies: 1
    Last Post: 09-27-2008, 03:50 PM
  3. Engine 97 Stratus 2.4, 420A heads, inakes, header, and Neon 31th trans...
    By ShelGame in forum Parts For Sale
    Replies: 27
    Last Post: 01-12-2008, 08:47 PM
  4. 90 VNT with broken trans case
    By METZ in forum Transmission
    Replies: 15
    Last Post: 04-12-2007, 08:35 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •