G Force Crossmember 700R4 Transmission Angle

[Michael Bennett]

My transmission agle seems wrong. With the car on the hoist and the frame level, the transmission is tilted up 2.5 degrees at the rear. When I drained the fluid it actually came out of the front of the pan first. That's what made me notice it. The angle between my trans and driveshaft is 7 degrees which seems like way too much as well. I'm measuing the trans angle off the pan rail surface. The trans is mounted using a G Force crossmember for my 700R4 and energy suspension mount pn 3.1108G. The small block chevy is mounted using stock car clamshells on the engine and factory style V8 mounts on the frame. Also, I am getting vibration at the big end of the drag strip and I believe it's coming from the driveshaft to trans angle. Trying to figure out where I went wrong? What's wrong with this combo?

 

[superbon54]

Your trans mount bushing might be too tall. Energy has 3 or 4 different versions. Also, how are your motor mounts?

 

[84cutspreme]

I have same setup with 350 sbc mounted to 700r4 with g-force crossmember. I have stock style engine mounts and trans mounts. No issues

 

[Michael Bennett]

I have same setup with 350 sbc mounted to 700r4 with g-force crossmember. I have stock style engine mounts and trans mounts. No issues

Whats your driveshaft to trans angle? Have you measured it?

 

[Michael Bennett]

Your trans mount bushing might be too tall. Energy has 3 or 4 different versions. Also, how are your motor mounts?

I have the taller, 2" version. They list four but only due to color, red or black. The shorter version is 1.62" I believe. Thats not enough to fix the angle.

 

[fleming442]

Thats not enough to fix the angle.

How much do you need, then?

 

[motorheadmike]

It is wrong. Really wrong. I heavily modified my G-force crossmember to drop the tail shaft. It is in my wagon build thread (see sig for link, and do a search).

 

[superbon54]

If your true angle is 2.5 deg up, and you’re shooting for 1 deg down, usin some trig the tail needs to drop a little under 3 inches. This is using a motor mount to trans mount distance of 48” (assumed value, didn’t research or measure).

Make sure you’re not running the isolators between the x member and frame and also that you’re not using any of the shims that came with the ES bushing. If both of those are the case then it’s most likely that either the cross member is incorrect, the motor mounts aren’t correct or your frame is tweaked.

 

[84cutspreme]

Whats your driveshaft to trans angle? Have you measured it?

Whats your driveshaft to trans angle? Have you measured it?

I did measure it when I did it but that was years ago. Shot for 3 degrees and I think that is where we left it

 

[Michael Bennett]

I'm on vacation this week, so I'm headed back out to the shop in a few min. I'm going to do some measuring so I can use actual math. I think part of my issue might be the Wagon CC springs I used to lift the rear of the car. I like the muscle car look but it may be part of the culprit. Also, I just ordered the shorter trans mount from Summit right now, but if you use assumed numbers, lowing the trans only a half inch only changes the angle by less than a degree. 6 degrees is still too much. Also, just wanted to mention that the car drives fine under normal circumstances. I don't notice any vibration until the big end of the drag strip at over 100 mph. I do want to fix that though.