ggorham2

So I'm swapping in a 2003 tj a 2004 LS1 motor from a gto with the 4l80e transmission. I'm using the Novak Mounting brackets and while I have some modification to do for the steering shaft angle I'm noticing that the alignment is off center about 1 inch to 1.5 inch to the drivers side. Everything I've searched indicates this shouldn't be an issue as many vehicle have a similar offset. I'm just wondering if this will be an issue for the driveshaft since it doesn't exactly lineup to the output shaft on the trans?

G Atsma

The U-joints should compensate for it.

jetech

Here is some reading for ya
https://www.jeepfan.com/tech/driveline-angles/

LS1 TJ

Per my drive shaft shop guy I went with a constant velocity rear drive shaft on my 98 TJ LS swap. I've never measured the offset. Never had a bit of problem in 10 years.
I did have to reposition the steering shaft a little bit to clear the engine.

LS1 TJ

So just for fun I measured the from TC output to frame rail.
Right side. 17 I/2".
Left side. 19 1/2".
The muffler makes the measurement a bit off as I had to go around it but its close.
I am running a Expoder 8.8 so its a bit off center compared to the TJ 35.

Toddoky

LS1 TJ

I did my swap over ten years ago and swap mounts weren't available at the time so I made my own. Cut the 4 cylinder engine mounts off the frame. Bought a set of street rod universal frame mounts and fabbed up a set of engine mounts. I'm running the stock skid plate so I just drilled new holes to match the 4L60E trans location. Used a mid-80s rubber trans mount. Its worked well over the years. I used Novak trans and TC conversion parts including their radiator. I'm running a 241R TC out of a Rubicon. I had to do some mods to the 4 wheel drive shift lever to get it to work. If I did it over I would buy the Novak TC shifter conversion. Mounted the ECU on the tray by the brake booster. Howell LS wiring harness and ECU.
The Novak conversion parts allow you keep the stock speedo and include a spot for the 4L60E VSS. At the time there wasn't a signal conversion for the tach. I belive there is now. I mounted a small tach behind the A pillar. Also I didn't like the stock oil pressure gauge so I mounted on top of the tach.

Toddoky

LS1 TJ

As I recall it was for and aft. I will check tomorrow. A bit chilly here in MN. Got up to a balmy 4 degrees here today. It's my summer time gravel road cruiser or mall crawler as some would say. My snow plow in the winter. Almost 18" on the ground.

gofastwclass

iTrader: (2)

I guess I shouldn't cry as it can always be worse, it was a high of 18 here...

Michael Yount

iTrader: (1)

You’re offset an inch to the (US) passenger side. Mine was intentionally offset 1/2” towards the passenger side. Never a problem for me with DS or ujoints.

LS1 TJ

I did some measuring in regards to the trans mount. I'm using the stock skid plate. I didn't remember until I slid underneath the Jeep but the stock skid plate has a 4"? square hole right where the trans mount wanted to be. So I welded a 1/4" plate the fill the hole. I slotted the bolt holes to give me some for and aft adjustment. The bolts are about 7 1/8" from the back edge of the skid plate.

ggorham2

Thanks for the info, Still have a vibration when stomping on it but alignment is still needed.

My Setup is a 2003 tj with LS1 at 385hp at flywheel, sanderson block hugger headers, dual exhaust into flowmaster HP2, 4l80e with novak adapter to np 231 with teraflex SYE to tom woods shafts to a ford 8.8 with barnes truss, chromoly shafts, detroit locker on 35s and 4.10 gearing. In the shop now for alignment, troubleshooting a soft shift between 1-2 and tightening up new rear disk brake system as e brake doesn't hold it.

Overall I'm gonna first wait for the alignment before figuring out if it being to passenger side 1-3/8" is a issue or not. The way the LS1 pulley just misses the steering shaft I won't be able to move it to the drivers side without getting a smaller pulley. Everything I've read and got for a response the old hotrods would be off 2 inches and had no issues.

Toddoky

Do you have a single U-joint at either end of your drive shaft, or is it configured with a double Cardan joint at one end?

ggorham2

I have a double on both the front and rear shafts.

Toddoky

Is the centerline of your rear pinion in-line with the centerline of your driveshaft, or is there an angular disparity between them?

ggorham2

Yep, rear pinion is about .5 - 1 degree down. It rises when you give it gas. I need to see after alignment if the issue is resolved. I welded in basically all the brackets on the rear, new adjustable uppers basically the whole driveline has been rebuilt or is new.

Toddoky

With your 8.8 rear end you have a completely non-stock drivetrain and I think it will be much easier to diagnose the issue by taking baseline measurements of your drivetrain geometry so you can eliminate possible causes in a logical manner. If you drop a plumb bob to the ground in the middle of the front and rear frame crossmembers and snap a chalk line between those points it will give you the centerline of your chassis that you can reference to when dropping a plumb bob from the front centerline of the crankshaft and then also the centerline of the output shaft yoke on your transfer case. Measure the offset distance between each of those points and the chassis centerline to see if they are equal or not, which will tell you if your drivetrain is installed parallel to the chassis centerline, or cocked on an angle.

LS1 TJ

I also have an 8.8 on my TJ. I did purchase the JKS? length adjustable control arms. They also swivel for more articulation. Let check a little later tonight and I will do some measuring from side to side and drive shaft angle.
Since you are running 35's do have a pretty big lift?

Toddoky

Don’t overlook the possibility that you are exceeding U-joint working angle limits on acceleration due to the sum of compound angles. The effect of the lateral offset between your transfer case output shaft and rear pinion on your U-joint operating angles needs to be added to whatever amount of vertical U-joint operating angle you have to determine what your total operating angle is.