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Author Topic:   Breaking powerglide cases NEED HELP
Eagle71
Dirt Full Roller

Total posts: 39
posted August 14, 2005 11:32 AM  
So far this year I have busted 4 cases. These trannies are top of the line. I have changed, flywheel, torque converter, driveshaft (drive shaft is balanced), installed long slip yoke, I even cut the x-ing out of the car and redid it stronger, put in long doll pins. The only thing I have differnt from last year is the rearend housing. I slip yoke is not hitting the tail stock. I have cracked the bell housing 3 times, cracked it over the reverse pump once and have knocked out 3 tails seals. Please help, any suggestions welcome, I'm at my wits end with having to fix this every month. I think I'm gonna snap if I can't get this fixed.

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted August 14, 2005 12:31 PM  
more then lickley its your tranny mount if you are using a poly mount go back to a stock rubber they have more give and wont crak your tranny.
We fought this for a long time and that is how we fixed it

mansfief
Dirt Maniac

Total posts: 128
posted August 15, 2005 06:56 AM  
My set up is solid motor mounts and stock rubber transmission mount. Slide your drive shaft in the tramsmission and pull it out 1 and 1/4 inch. If you can't bolt the drive shaft in with that measurement, then your drive shaft is to long. That is the setup I have and have had no problem.

mansfief
Dirt Maniac

Total posts: 128
posted August 15, 2005 07:01 AM  
Forgot to mention, do this at ride height. Gees, its to early in the morning to try to type.

0LT
Dirt Full Roller

Total posts: 38
posted August 15, 2005 05:55 PM  
Do you run a rear motor plate or rear mounts? If so get rid of the trans mount and let the tranny float on the back of the mounts. Problem solved by removing the torque issue on the tranny case.

If not, it sure sounds like your driveshaft is to long. Why do you think it is not to long? Some PG output shafts have short cut splines on them. When the drive shaft yoke runs through the seal under hard braking the yoke may hit the end of the splines, but not hit the tailshaft seal, and bingo broken tranny. By installing a longer yoke you may have made the problem worse. Something to check anyway.

Now that you have paid for 4 PG rebuilds, dontcha wish you had bought a Falcon/Brinn/Bert?

0LT


Raz_900
Dirt Forum Champ
Total posts: 635
posted August 15, 2005 07:52 PM  
If using a stock metric driveshaft, it will look like it fits but do just what you're describing. Get a long yoke and it might fix it. I think Strange sells them for ~$60.

Or, buy a Dedenbear case and call it a day. After wasting a total of 5 in mine over about 15 races, I coughed up the $900 for the Dedenbear. 2+ years without a hiccup. It was freshened last year just because but I was told it didn't show any signs of wear at all. Seems to shift harder than the stock case'd builds did too.

After seeing the guy that pits next to me frag a clutch and have the pressure plate come up through his floor and rip the dash apart, it's a little reassuring knowing that case is SFI approved as a scattershield too. It has a 1/4" steel liner inside the case.

Eagle71
Dirt Full Roller

Total posts: 39
posted August 15, 2005 09:22 PM  
OLT, I'm not allowed to run a brinn or any such transmission. I can slide my slip yoke by hand all the way into the tail shaft no problem. I have 1 5/8" of travel before it would bottom out, and it looks like I'm getting only about 3/8" travel inward. I have no mid mounts.

Iowa dirt track girl I have a stock rubber mount in the rear, it has 2 bolt holes through it, I was thinking of finding one that is a one bolt hole.

I found that the left side motor was loose, not sure if that had anything to do with it(again) but I tighten the heck out of them to make sure. I pulled my gears out and them checked just in case and they looked good. I'm calling the place that balances my driveshafts to find out how many RPM's they are balancing them at. Also how much do you think that having the driveshaft aligned with the rearend gear would play into it? Seems like the pinion center maybe 3/8" to the left (driver side). I'm running about 5 degrees pinion angle thats including driveshaft and pinion.

I also spun the engine over what watched the crack and flexplate, everything seemed to be good. Also noticed that the flexplate bolts in the crank were touching the torque converter, any suggestion? Put a washer betweem flexplate and converter?

Thank you all very much for all the advice

mudcrasy
Dirt Roller

Total posts: 9
posted August 15, 2005 10:15 PM  
I had the same problem with turbo 350s.I did like chased it around the world for 3/4 of the season.Tried raising ride hight,changing pion angles,gears and rear ends.I ended up putting the long slip yoke on.This set the slip yoke travle to an 1 1/4 like posted above.The problem has not returned.If the only thing different is the rear end check the yoke lenght.Ford has 2 different lenght yokes a long and short.That was onther ting I had to get the long yoke. Hope this my help.

Raz_900
Dirt Forum Champ
Total posts: 635
posted August 17, 2005 07:14 PM  
After some careful measured I'd found mine was only running in 3/4 of the bushing in the tailshaft. Basically, the driveshaft was whipping around because it wasn't on the tailshaft far enough. The longer yoke on the front of the driveshaft makes certain it's all the way through the bushing and on the tailshaft enough that it stabilizes it.

powerglides
Dirt Freak

Total posts: 374
posted August 18, 2005 05:09 AM  
OK: Lets go down the list.
1. What gear do you race in?
2. Do you run a stock driveshaft?
3. What rear suspension do you have?
4. What is your pinion angle from level at ride height?
5. What is your driveshaft angle from level at ride height?
As far as the converter bolts. Unbolt converter and slide it back against tranny now try to slide a washer between converter pads and flexplate. If 1 washer fits but not 2 then put the washer in front of flexplate. If 2 washers fit but not 3 then put 1 washer between flexplate and converter pads. If 3 washers fit put 2 washers between converter pad and flexplate. If 4 washers fit get a converter spacer kit from Bushore or Coan!



Eagle71
Dirt Full Roller

Total posts: 39
posted August 22, 2005 08:42 AM  
Powerglides
1. 2nd gear 1 to 1
2. Stock driveshaft that has been cut and balanced at 2000 rpm
3. Stock metric-trailing arms
4. 4 degrees pinion angle
5. 2 degrees drive shaft angle
Tried a few small things, tranny looked fine, won the feature!! but gonna put it up in the air to make sure.


powerglides
Dirt Freak

Total posts: 374
posted August 23, 2005 04:47 AM  
OK here is what is happening. And I have seen this lots of times. The Stock driveshaft is not strong enough to withstand 6500 rpm! It balances fine at 2000 but when you spin it up it begins to bow (like a piece of spaghetti) in the middle and whips the tranny into submission. Low gear racers do not have to worry because the driveshaft never goes over 3500 rpm. But high gear racers (you) need to get a thicker tubed driveshaft.

Eagle71
Dirt Full Roller

Total posts: 39
posted August 23, 2005 08:33 AM  
Thanks, Ordering a new one today, from fast shafts or colman racing products

    

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