4L60E transmission

[Diesel Dan]

Would like to see some pics of how others clearance the tunnel for a 4L60E install.
So post'em if you have them and how close you managed to get the output shaft to line up with the rear axle.
Also if you moved the front of the engine towards the passenger side the same distance.

[HAULIN' IT]

Would like to see some pics of how close you managed to get the output shaft to line up with the rear axle.
Also if you moved the front of the engine towards the passenger side the same distance.

Having the engine/trans off-set a little compared to the pinion is not a real concern. You do want the engine/trans. assy. "square" in the car...angled would not be "correct". If you move the back over, you move the front over as well. Lorne

[Diesel Dan]

Having the engine/trans off-set a little compared to the pinion is not a real concern.

I wouldn't consider 1" offset minor especially on a single u-joint setup.
Compound angles are not a good thing unless I run dual CVs.

Wish I would have measured the engine and transmission C/L before pulling them.
Oh well, my bad since I ASSumed the pinion was centered in the chassis but didn't account for the torque arm.

[HAULIN' IT]

Dan, The other day I wrote this big long post on your situation & when I went to submit it...the screen blinked & I lost it all. The basics were this: I can see Two sides to this from experience fooling with vehicles for a bunch of years.

On the thought of: "I wouldn't consider an inch minor"...I've been around vehicles that were built "too straight", as in the builder worked very hard to put the engine/trans assy. as close as possible to a straight line tilting the tailshaft down & rear axle up to make NO working angle in the U-joints. The Two that I can think of both had a droan at cruise speed. The one was "fixed" by placing a 1/2" plate under the trans mount.
Along the same lines, years ago my friend installed a 9" rearend out of an early '70's truck into his '65 Chevy shortbed truck. Everything went fine up until time for the driveshaft when it hit the Right side of the crossmember (these trucks have a heavy crossmember with a hole in the center for the driveshaft to pass through) before it could be attached to the rear yoke. The problem? Those Ford trucks have a pinion 4" off-set to the Right to help make up for the off-set engine to clear the steering box. The outcome was a good sized notch to make the shaft clear. He drove that truck for years & many times at rather high speeds. The truck did have a slight whine/droan at the transmission at cruise speed, however other Richmond 5/6 speed owners have commented on similar noises. Who knows, maybe it was the WAY off-set pinion/driveshaft angle?
Another thought, at cruise speed is really the only time you would/could find a problem (droan, vibration, ect.) That One inch off-set in the terms on angle is no different than the average pickup truck going down the road...only turned sideways.

Now the other side: Virtually every V-something engine placed in modern time (mid '60's up?) has the engine off-set to the Right. So if your basing your engine/trans. install along a centerline of the car...this wouldn't be the GM would/did it so really you would have better results (steering clearance, ect.) moving the engine over anyway. My Two Cents. Good Luck, Lorne

[chevyart]

lorne explained it real good. 60s cars all had offset motors to sllow for steering etc. and the pinion shaft centerline was usually always offset in rear housing(1- 1 1/2"). bottom line is all you need for proper operation is for engine-tranny centerline to be absolutely parallel with pinion shaft centerline.offsets front and back to a certain degree are OK. the part that is adjustable to the builder is the engine tranny centerline angle( shouldnt exceed 3 degrees down) and the rear pinion shaft centerline moves under load. and is not adjustable on factory cars, but is initially set when the 4 link brackets are welded into place on the rear end housing( rear upper factory can be adjustable(for pinion angle) when you get aftermarket one with heim joints.. these 2 parts(engine and rear) should be parallel(maybe 1 degree difference) under full load. they can be at different heights also, just need to be parallel under load.. real trick is to figure out how much the rear pinion shaft moves UP under load.. leat spring cars usually give up 5-7 degrees up under load. factory GM coild spring cars(4 link) usually gives up 4-6 degrees UP. ladder bar and 4 link race cars usually give up 0-1 degree up. easy example engine angle level(o) on vega rear(factory 4 link), pinion angle at dead rest should be 4- degrees down, and under load it moves up 4 degrees and is parallel with engine-tranny angle.hope i explained that right art

[Diesel Dan]

Thanks for the replies guys.

Definitely not trying for a 0 angle drive line. As stated that is not good for u-joints since you do need a minimum operating angle for longevity and performance.
Just keeping drive line offset along one plane. One inch offset by itself is not a bad thing but having one inch side to side along with the standard vertical running offset is asking for vibration trouble.

A little driveline 101, Art and Lorne feel free to add to this.

Vertical offset + horizontal offset = compound angle
Single u-joints + compound angle = vibration/drone

Single u-joints need to be in phase to cancel out vibrations.
Compound angles can be used along with constant velocity(CV) joints.


I did manage to get the engine/trans mounted 1" towards the RH side of the car.
Did I absolutely have to?
Don't know but it would have bothered ME knowing it was off.

[HAULIN' IT]

I did manage to get the engine/trans mounted 1" towards the RH side of the car.
Did I absolutely have to?
Don't know but it would have bothered ME knowing it was off.

That's Great... I think in the long run it will be time well spent. Lorne