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Author Topic:   Broken Drivetrain
Robert Carson
unregistered Total posts: 181
posted October 15, 2002 01:44 PM
Trying to figure out what happened: Limited Late Model, stock front clip actually full frame car, multi-leaf, solid engine mounts, engine-to-tranny mid-plate, T350, rear tranny brace (brace is constructed out of square tubing with 2 rubber “doughnuts” that the tranny rests on), stock drive shaft, 9” rear end. Been running this set-up for 1.5 seasons. Have cracked bell housing twice now. 1st time thought it was fluke (my mistake for assuming maybe uh?).

Last weekend was last points race of season. 1st time out since recently rebuilding tranny (new pump & planetary). Started on pole in heat race, race went green, made it to flag stand when loud “CRACK/POP” & I coasted to stop all the way around track to pit exit.

Results: bell housing cracked totally in 2 from driver to passenger side, drive shaft twisted in two, pinion gear snapped in two behind yoke, went from finishing season 6th in points to 7th.

Any ideas as to where to start looking?

pipes
Dirt Roller

Total posts: 21
posted October 31, 2002 07:19 PM
I would reccommend that you make a new transmission rear mounting plate that will accept the stock tailstock transmission mount that uses 2 bolts at the tailstock and 1 stud or bolt at the crossmember.
with the stock mount used it will allow the trany to twist with the torque of the engine,even with solid mounts and a roll cage there is still a certain amount of chassis flex under engine accelleration that could be causing your problem. rigid mounting will break parts at the weakest point eg. the tranny bell housing.
the driveshaft destruction was most likely a result of the bellhousing breakage allowing the tranny to move out of the plane of the driveshaft.
hope this gives you a starting point to solve your problem.

Robert Carson
unregistered Total posts: 21
posted November 01, 2002 01:30 PM
Appreciate the reply. I believe the tranny mount I've created, when compared to a stock mount, takes into consideration the same axial forces that would be present due to torque & flex. Was blessed by my tranny sponsor too.

It would appear from discussion with a local driveshaft shop that it was the driveshaft that failed initiated the damage.

Don't know that I'll ever know for sure though. Keeping my fingers crossed that it doesn't happen again. Take care

DMA Racing
Dirt Forum Racer

Total posts: 82
posted November 01, 2002 09:06 PM
i had the same thing happen this year two different times,found out the drive shaft was about 1 inch to long.

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