LQ4/4L80e swap help

[mdelosrey]

Hello everyone, I'm in the middle of the swap and had a question about the CPP transmission crossmember and oil pan clearance. With the motor in the rear most position on the sliders and the transmission crossmember mounted on top of the lower flange of the frame rail, the oil pan makes contact with the front subframe web. If I mount the transmission crossmember underneath the top flange of the frame rail, the oil pan has plenty of room but the driveshaft angle looks steep. Any ideas? I was thinking notch the front subframe and mount transmission crossmember to bottom flange of the frame unless there is an oil pan I can swap in that will alleviate the clearance issue.

Transmission crossmember orientation (upside down?)


Oil pan/front subframe clearance:


Harmonic dampener clearance.


Transmission housing/ frame rail angles (xmember upside down?):

[mongocanfly]

Your trans needs to be at a downward angle...most try for around -3deg....but it needs to match the up angle of your differential.....so if your diff angle is +3deg your trans needs to be -3deg.....first check angle of your diff...this would be much more accurate if your body was on frame...try it with your frame level....

[dayj1]

I looks like your engine is too far forward. Move the engine stands back to the rear set of holes at the crossmember and it should fit better. You may have to drill a hole for the lower stand bolt on each side, but that's no big deal.

[binford]

I'm using the stock cross member, with a stock 350 rubber mount. I had to slide the cross member way back as the 4L80e is longer then the turbo 350 it is replacing.
The stock truck pan does clear, but its close.

The Hummer pan will gain you an inch, but each pan has pros and cons.
There's an oil pan thread that has drawings of each pan the measurements. The Caddy CTS is another pan.

x2 on the 3 degree pointing down. I would get a digital angle finder and measure how many degrees the rear pumpkin is pointing up and that is what you need to match, if you have a 1 piece drive shaft.
I have the two piece drive shaft. so the front shaft will get shorten at some point, not quite there yet.

edit: It does look like the engine is mounted forward as my trans is farther back. Using ebay motor mount plates

[mdelosrey]

Thanks everyone. I moved the motor mount stands one position to the rear and redrilled the subframe hole as needed. Motor now sits much better.

More dampener clearance.


Trans more "level"


Trans crossmember on bottom frame rail.