How weak are the G56 transmissions?

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unfinished business

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Ok, I have been seeing more and more posts about G56's blowing up; 4th gear in particular. So, I am wondering just how weak are these tranmissions? I have a southbend 3250DD with the SFI flywheel in my 07 2500 4x4. My plan was to do a small set of twins and drag race and sled pull the truck every now and then on the weekends. So how have these transmission been dealing with mild abuse? My fueling will be mostly stock, so the HP should be in the mid 500's I would estimate.

Just looking for opinions.

Thank you,

Paul
 
I have found that if you will stay on the low side of the transfer case when pulling and don't do boost launches at the track they will usually be ok around that power level. The downfall to the g56 is the aluminum casing. The internals are fine but when put under a load the case flexs and the countershaft takes a ride:)
 
Mine feels like the fourth gear syncro is gone, if you are not easy it will grind going into gear. Do you guys think I would be ok just changing out the syncro, or would I need other parts to rebuild it?
 
Originally Posted by Bad-Duvall
HAHA! I have toasted 3 now 4th 2 times and 2nd once THEY ARE JUNK! what happens is there is no center support bering and it allows the shafts to flex and pushes the gears away from each other and BAM-O Im in the process of swaping in an NV 5600 in my 07. O yea the last time i was just playing on the street when it happend!
 
I think the g56 is a good trans for a stock truck but once you add extra power and start playing it's a ticking time bomb. I have been through 2 of them the 1st one went while i was on the street it blew 4th gear and the second tranny lasted 4 days. For some reason i pulled in 2nd high and BANG the case busted.
 
I had one sieze up on me coming off the interstate. It locked up the rear end and exploded the clutch. This was on a stock truck with less than 20,000.
 
Alot of the problem with them is ppl running the high side of the tc sled pulling. Witch is what happened to me. Selling the g56's and going auto!!!!!!!!
 
I dont think anyone is selling them yet. That isnt the weak link in them, its the gears!!
 
SPEEDSHIFT said:
Mine feels like the fourth gear syncro is gone, if you are not easy it will grind going into gear. Do you guys think I would be ok just changing out the syncro, or would I need other parts to rebuild it?
Click to expand...

Same problem with mine but its 5th gear....would also like to know.
 
Change the syncro and you should be fine. There are pretty simple inside. Biggest thing is loose the ATF! Get some good gear oil in there, they shift easier and make less noise.
 
Alot of the problem with them is ppl running the high side of the tc sled pulling. Witch is what happened to me. Selling the g56's and going auto!!!!!!!!
Click to expand...
This surprises me...I figured you'd atleast go NV first...
 
My from day one that I had it with 20 miles on it. Woud give me problems going into reverse. Not problems other than that this far. The couple times I have pulled I pulled in Low range so hopefully that will help I don't have money for a new trans now. Heck I need one in my 96 first
 
07dodge said:
Change the syncro and you should be fine. There are pretty simple inside. Biggest thing is loose the ATF! Get some good gear oil in there, they shift easier and make less noise.
Click to expand...

This is the first I have heard of puttin gear oil in one. Mine shifts pretty well now, but if it can be improved I would go for it.

Can anybody else comment on using a differant oil besides ATF in their G56s?

What are you guys that have changed the fluid runnin?

It seems reasonable to me that a heavy gear oil would protect against the shock load better then the thin ATF, but I didnt know if gear oil would flow well enough to lube the trans properly.
 
I run a 75-90 molly blend gear oil from schafers. If you run one for awhile and take it apart and look at the gears you would, with out a doubt put something besides atf in it. My gears had weird wear marks on them. When you take out that dual mass and put in a solid flywheel and you hear that gear chatter louder than ever, ya its doing something inside there.
 
07dodge said:
I run a 75-90 molly blend gear oil from schafers. If you run one for awhile and take it apart and look at the gears you would, with out a doubt put something besides atf in it. My gears had weird wear marks on them. When you take out that dual mass and put in a solid flywheel and you hear that gear chatter louder than ever, ya its doing something inside there.
Click to expand...

Thanks.

That makes sense to me. I never thought about what takin the DMF out would do to the trans, but I may have to try that. I am runnin RP synchromax right now. I put it in at about 20k, but now at 55k I think when it warms up a lil I will put something heavier in there.
 
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