need trans mount advice

**johnquick302** · 04-17-2010, 09:34 PM

Originally Posted by jharris

and what size back space pro stars were on the cobra ? a 15 x 10 with a 6 inch backspace works on my car with a 28 10.5w but i am buying prostars they only come in half sizes so idk if the 6 1/2 will be to much

6.5

**jharris** · 04-17-2010, 09:35 PM

ya this is jason. i was gonna just weld a 3/8 plate on it i figured that would work

**jharris** · 04-17-2010, 09:35 PM

alright thanks for the advice

**RSWANNABE** · 04-17-2010, 10:31 PM

I don't know the exact situation you are encountering, but I needed to move the mount back on one of my cars. I had a stock cross member and cut the spot welds on the mounts, moved the cross member back and re welded it. Worked fine. Maybe this is an idea for you.

**cjmatt** · 04-18-2010, 10:29 AM

is there a generally accepted way to set the driveline angle? what should I be shooting for? I want to mount up my trans today as well, but dont know how much to angle it

**beertestr** · 04-19-2010, 09:13 AM

Originally Posted by cjmatt

is there a generally accepted way to set the driveline angle? what should I be shooting for? I want to mount up my trans today as well, but dont know how much to angle it

Two answers.
1. The least amount, and
2. the vertical angle (of both lines intersecting a horizontal line) to your axle pinion angle at ride height. If the pinion is 2 degrees nose up, then you want the trans centerline 2 degrees nose down. U joints vibrate due to the varying speeds as you spin a driveshaft, the object is to cancel the fornt joint vibrations with the rear. Putting the pinion and tailshaft at vertical angles creates cancellation of the vibrations.

FYI you also don't want the pinion and tailshaft directly in line either as this will not allow the needle bearings in the u joints to rotate and they will lose lubrication over time..

Hth

**cjmatt** · 04-19-2010, 10:23 AM

Originally Posted by beertestr

Two answers.
1. The least amount, and
2. the vertical angle (of both lines intersecting a horizontal line) to your axle pinion angle at ride height. If the pinion is 2 degrees nose up, then you want the trans centerline 2 degrees nose down. U joints vibrate due to the varying speeds as you spin a driveshaft, the object is to cancel the fornt joint vibrations with the rear. Putting the pinion and tailshaft at vertical angles creates cancellation of the vibrations.

FYI you also don't want the pinion and tailshaft directly in line either as this will not allow the needle bearings in the u joints to rotate and they will lose lubrication over time..

Hth

K, Ive got the trans mount pretty much completed and the trans as far up as I can get it. The side connector is my limiting factor as its kind of bulky, but I am measuring about 5* from level on the damper. Is it OK to have the motor angled like this?

Ive also read that you need to mount the pinion a little negative to take into account for the bushing under load. I was told to give the pinion 3* negative angle to the angle of the trans. So I would be mounting the pinion at 2* from level if my motor is at 5* opposite

**beertestr** · 04-19-2010, 11:52 AM

Originally Posted by cjmatt

K, Ive got the trans mount pretty much completed and the trans as far up as I can get it. The side connector is my limiting factor as its kind of bulky, but I am measuring about 5* from level on the damper. Is it OK to have the motor angled like this?

Ive also read that you need to mount the pinion a little negative to take into account for the bushing under load. I was told to give the pinion 3* negative angle to the angle of the trans. So I would be mounting the pinion at 2* from level if my motor is at 5* opposite

Which motor are we talking about here? LS?? Which oilpan? FWIW PIckups with LS motors (factory not mine

) are mounted at 6 degrees, and the oilpan is designed with that in mind. I'll have to look through my list o'info and see what an F-body pan angled for. Either you should be fine, it might throw the dipstick reading off a bit but other than that no probs.

As for the 3 degree bushing thing, if you are running 1/4's all the time, that will help with u-joint loads on hard launches. Running down the highway at 70 is not putting a lot of reaction torque load on the bushings, you would likely have misalignment an possibly some vibration. Also, if you are running urethane bushings on the rear control arms, you can run less angle, as they deflect very little.

If you wanted some tuning options, set your x member up with a 1/4" spacer under the mount. That way, you have room to add/remove shims to play with driveline angle a bit.

If the connector is getting into the tunnel... well BFH's do wonders for that. Careful hammering can form a "Recess" that can be smoothed to look factory. I did that on my Caprice to fit the reverse lockout solenoid from the T56.. looked way better than I thought.