Author Topic: another broken gm trans.  (Read 783 times)

0 Members and 1 Guest are viewing this topic.

Offline Ron 1

  • GBO Supporter
  • Trade Count: (1)
  • Contributor
  • *****
  • Posts: 486
  • Gender: Male
another broken gm trans.
« on: January 29, 2011, 06:33:53 am »
it is getting old as this is the 4th tranny i have broke
the 350 turbo is bolted to a 208 transfer case and the trans case breaks on the top both ears that bolt it to the transfer case adapter mount
i am a lil hard on them but i should get more then 1 run out of a trans. the internal parts are still good but need to be put in a different case. i put in new mount for the tranny and new motor mounts. the brace from the transfer case to the bell housing gets bent too. i am thinking of making a1/4 in. plate to mount between the transfer/trans and bolt it to the cross member. any other ideas?
this is in my jeep it has a 400 hp small block  308 gears a 2500 stall converter and 38 in boggers
i use it to race in the mud and play in the sand dunes. i am starting to have a hard time finding more turbo 350 transmissions and would like to get more runs out of them. thanks for any help or advise on this would be greatly appreciated           
       rw
A man with a briefcase can steal millions more than any man with a gun. - Don Henley


Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 12754
Re: another broken gm trans.
« Reply #1 on: January 30, 2011, 03:24:17 am »
what about a turbo 400?
sixgun addict

Offline Ron 1

  • GBO Supporter
  • Trade Count: (1)
  • Contributor
  • *****
  • Posts: 486
  • Gender: Male
Re: another broken gm trans.
« Reply #2 on: February 01, 2011, 05:47:06 am »
i do not know if the case on a 400 would be any stronger  i do know that it needs a different adapter to bolt to the transfer case tho.  it also needs a different torque converter  the rear drive shaft determines what i can do as far as changes go. other than that i would need to move the motor forward in the frame.
right now the rear drive shaft is no longer than 10 in. there is no tube left slip joint and yoke welded together.
 i did find a heavy duty after market 350 turbo case and had it rebuilt and beefed up
i was also told to go to a 205 transfer case that is 2 in. shorter and 100 # lighter  that will help with the rear drive shaft length
 rw
A man with a briefcase can steal millions more than any man with a gun. - Don Henley

Offline Slowpoke Slim

  • Trade Count: (18)
  • A Real Regular
  • ****
  • Posts: 581
  • Gender: Male
Re: another broken gm trans.
« Reply #3 on: February 09, 2011, 05:30:59 pm »
Well my first thought was why in the heck are you running a 308 gear and 38 inch tires? That's a heck of a torque load on the drive train. I would drop the gear ratio a BUNCH. That will help.

Then on your second post, if I read you right, you've taken the slip yoke and welded it solid on your rear driveshaft?

You are either A) breaking the housing from the torque load of very tall gears with large tires, or B) you are beating the driveshaft into the transfer case hard enough to break off the trans ears when the rear suspension flexes over uneven ground.

The definition of insanity is repeating the same steps and expecting different results.

 :D

I'd be making some changes to your setup.

Offline Bigeasy

  • Trade Count: (5)
  • Senior Member
  • *****
  • Posts: 2056
  • Gender: Male
Re: another broken gm trans.
« Reply #4 on: February 09, 2011, 05:40:30 pm »
The combo you are running puts a lot of stress on your drive train.  Any misalignment in your drive train components will cause failure such as cracked housings.  Never built a truck, but have done quite a few muscle cars, and have found cracked casings are almost always a result of uneven forces being applied.

Larry
Personal opinion is a good thing, and everyone is entitled to one.  The hard part is separating informed opinion from someone who is just blowing hot air....

Offline hillbill

  • Trade Count: (0)
  • Senior Member
  • *****
  • Posts: 3365
Re: another broken gm trans.
« Reply #5 on: February 09, 2011, 05:59:10 pm »
yu need to switch to gears in the 4.00 range.3.08 are kinda high for what yur dooin.lower gears will cause lower stress on yur drive train.actually a 4.56 would be good for what yur doin.they aint good for hiway use but good for offroad use.those big tires put a lot of stress on everything when trying to take off with those high gears.pull them out and sell them to sumone trying to make sum mpg on thier less stressed truk!ive dun what yur doin and lower gears will just let yu roll off insted of stressin yur drive train.

Offline hillbill

  • Trade Count: (0)
  • Senior Member
  • *****
  • Posts: 3365
Re: another broken gm trans.
« Reply #6 on: February 09, 2011, 06:11:24 pm »
350 turbos are gittin hard to find, that for sure.

Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 12754
Re: another broken gm trans.
« Reply #7 on: February 10, 2011, 03:36:19 am »
got to agree on the gearing. Back in the day i had a new 79 chev pickup that had 343 gears and a 4 speed stick. I bought it new and put 40s on it. I think i broke things weekly with that combo and it was so guttless that when you excellerated up to 55 in 3 and shifted it to 4th that was as fast as it was going. Ended up with 3/4 ton running gear and 488s. With 40s the 488s worked fine on the road and gave it about the same gear ratio as stock tires with stock gears did. Id consider 488s with your combo too and nothing higher geared then 456s. I think youll find that you actually get better gas milage to boot with lower gears. Also for a thought id consider smaller tires. I know it goes against the grain but my truck was ran in quite a few bogs and seemed to run better times with 35 inch bfg mud terrains then it did with the 40 inch swampers. Personaly i think it was the fact that it was easier to control when it started boucing around. I think it would even be more of a problem in a little jeep. If i could set my jeep up the way i wanted and money was no object it would have a newer hemi with an 4 speed auto, 488 gears dana 44s  and 35 radial mud tires. Thing is its tough enough to come up with money to buy guns and loading supplys let alone do surgery on the jeep.
sixgun addict

Offline Old Syko

  • Trade Count: (1)
  • Senior Member
  • *****
  • Posts: 2652
  • Gender: Male
Re: another broken gm trans.
« Reply #8 on: February 10, 2011, 05:02:00 am »
Ron if you really want answers join the forum at the link below and go to the appropriate part of the forum for your needs and ask.  Without any slip in the shaft to make up for diff roll, you're lucky that is all the damage you're doing.
 
http://pirate4x4.com/welcome1.php

Offline Ron 1

  • GBO Supporter
  • Trade Count: (1)
  • Contributor
  • *****
  • Posts: 486
  • Gender: Male
Re: another broken gm trans.
« Reply #9 on: February 10, 2011, 05:57:45 am »
the drive shaft still has a working slip joint there is no tube for length
as for gas mileage the only road time the jeep gets it is on a trailer
i run it in low lock and i do get to use third gear at times that i do not get bogged down in the mud  real deep
to change out both sets of gears it will cost close to $2000 because i will need to replace the carriers from the 308s to a carrier in the 373 and up gear range
this set up is not perfect i know but it works well for the 31" 35" and so  so for the  38"40" tire classes
as far as diff roll it has ladder bars that stop the axle from rolling or twisting
  rw
A man with a briefcase can steal millions more than any man with a gun. - Don Henley

Offline no guns here

  • Trade Count: (1)
  • Senior Member
  • *****
  • Posts: 1730
  • Gender: Male
Re: another broken gm trans.
« Reply #10 on: February 10, 2011, 06:35:28 am »
My guess would be a mis-alignment of your x-fer case.  Seems like you are torqueing it too much in one direction.  Clocking it around might help.  Also, fabricating another cross-member or support might help to take some of the load off the casing.

NGH
"I feared for my life!"