Long story short: This tranny originaly came from BTO (level3 750hp(lol)). I broke it 3 times. The last time my friend rebuilt it. It has lasted but there seems to be a vibration in it. It has worn out 2 tailshaft bushings and I've replaced the rear seal several times because it starts leaking. I have replaced the yoke one time because it wears out one side of it. I know the pinion angle has not been set, could this be causing it? Or do yall think something in the trans is bent?

Hi, Interesting problem. It could be a bent transmission output shaft, however I am thinking more on the lines of your engine offset. Do you have Big Block frame mounts and a Big Block transmission crossmember ? I have heard the engine offset is ok if you use an offset transmission crossmember so that your engine and transmission are parallel with your driveshaft. Some people center the Big Block, to keep everything centered, and in a straight line. The only problem with that is you need custom headers like Lemon's etc. Now is there a point in Horsepower that it MUST be centered ? I assume you do hard launches at the drag strip, could an offset with more than stock HP cause a problem ?

if it wearing rear tail bushing on 1 side and vibrating. i would more put it on the driveshaft or pinion angle. a 700r4 is longer than the stock tranny. so than your pinion angle changes.

It could be a bent transmission output shaft, Do you have Big Block frame mounts and a Big Block transmission crossmember ? ?
I have correct frame and engine mounts. Crossmember is a BTO.
if it wearing rear tail bushing on 1 side and vibrating. i would more put it on the driveshaft or pinion angle. a 700r4 is longer than the stock tranny. so than your pinion angle changes.
I will get the pinion angle fixed and while I do I will replace the yoke, seal and bushing again and see it this corrects it, thanks.

It doesn't matter who made the crossmember. Is it offset ? If it is not, you WILL have vibration problems.

According to BTO's website, they do not show a different crossmember for a Big Block. I would assume your engine and transmission are now angled to the drive shaft and not parallel with it. This may be your vibration and the cause of all your failures ?

It doesn't matter who made the crossmember. Is it offset ? If it is not, you WILL have vibration problems.

According to BTO's website, they do not show a different crossmember for a Big Block. I would assume your engine and transmission are now angled to the drive shaft and not parallel with it. This may be your vibration and the cause of all your failures ?
I had the engine bolted in and bolted the trans to engine and when I put the crossmember up, the trans set right down on the holes in crossmember. I did not have to push the trans over to bolt it up. So is this ok?

I had the engine bolted in and bolted the trans to engine and when I put the crossmember up, the trans set right down on the holes in crossmember. I did not have to push the trans over to bolt it up. So is this ok?Patrick the side to side may be ok, but it may set higher or lower from that crossmember. I'm having the same issue at 100mph plus. Also im using a small bock x-member and installed it the same as you with no forcing it side to side the holes lined up perfectly.

Skip and Patrick, Do your valve covers look straight (parallel) with the fenders ? One gentleman, on this board, used a ratchet strap around the tail of the transmission, to pull it over 1/2 inch. For some unknown reason the engine likes to sit crooked, when it sits just on the engine stands. This has caused problems with header fitment at the steering box. When the tail shaft was moved over, more clearance was there ! See if this is the case with yours !

Skip and Patrick, Do your valve covers look straight (parallel) with the fenders ? One gentleman, on this board, used a ratchet strap around the tail of the transmission, to pull it over 1/2 inch. For some unknown reason the engine likes to sit crooked, when it sits just on the engine stands. This has caused problems with header fitment at the steering box. When the tail shaft was moved over, more clearance was there ! See if this is the case with yours !

Mine does that too. '69 with SBC and M20. I'm man enough not to need the strap wrench to move it though.:D

The small trick is to bolt the tranny in before tightening the motor mount bolts.

So yall are saying that I should loosen the trans mount bolts and push the tailshaft over and tighten it down? :confused:

There is another set of holes maybe 1/2'' over. I could use these. Which side should I push it over to?

Yes, push it over towards the passenger side. The transmission offset is 1/2" so if there are holes there... use them.

I'm gonna measure my tail shaft to see where it sets in between the frame... But also my valve covers look parallel with the inner fender wells. With the way mine is if you forced it over would put way to much tension on the motor mounts and frame mounts.