Trans not centered in frame?

[viking71]

I set my motor and trans last weekend. I think I'm ok with the motor looking out of level in the mounts but not sure about the trans. The support bracket isn't centered (1/2" closer to driver side) and drive shaft is 2" closer to the driver side of the frame. Any thoughts? I did ask about some of this a few days ago. I'd add pics but can't figure out how.

 

[broncodriver99]

From the factory they were offset about an inch to the passengers side. Are you sure you have your transmission cross member oriented correctly? It has an offset as well. Are you running a stock setup or what?

 

[viking71]

Yeah stock setup (302, C4, dana20). Sitting on the offset so the trans cross member is shorter on the passenger side. Center of drive shaft is 12 5/8" to driver inner frame and 10 3/4" to passenger inner frame. The motor mount bolts are sitting about 3/8" lower on the passenger side.

 

[broncodriver99]

Center of drive shaft is 12 5/8" to driver inner frame and 10 3/4" to passenger inner frame.

That sounds about right.

 

[viking71]

Thanks Broncodriver99. Do you think the motor mount bolts being offset sounds right too? I'm on a complete rebuild so just trying to get everything right.

 

[Galt72]

what motor mounts are you using? new or old stock, or the heavy duty ones? your motor should be level as possible side to side. I struggled to get mine square for weeks. I even had to trade out motor mounts because some fit differently for some reason. If your using the heavy duty ones there are plenty of posts about those things being cut wrong and not bolting up properly.

 

[viking71]

I'm using the stock style from Duff. The first ones I tried from AutoZone didn't work.

 

[broncodriver99]

Do you think the motor mount bolts being offset sounds right too?

I imagine they are supposed to be pretty close. There is likely enough variance in the aftermarket mounts and even your frame that perfectly level is unobtainable. I would just try to get it as close as possible and call it a day. Maybe try shimming one side or the other to give you a little more wiggle room.

 

[Steve83]

This shows the factory arrangement:



Being 1" off-center creates a 2" difference in measurements.

This caption describes how to neutralize the engine mounts:



This explains driveshaft angles:

 

[viking71]

Thanks Steve83 I'll check those today. 1/8" off center of drive shaft to frame differents. Trans 12 5/8" and rear is 12 1/2" to driver side. Passenger side shows the same difference in opposite order.

 

[Steve83]

The frame may be bent, or the rear springs may have slid on their bushings, or the bushings may just be that worn & collapsed. Or the rear axle perches may not have been welded on correctly. A bunch of small changes can add up...

 

[viking71]

OK, So going off of the chart Steve83 posted. I'm a 1/4" off to the driver side and 1/8" off to the passenger side. I'm sure you guys are thinking I'm beating a dead horse but I'm thinking I should shift 1/8" to passenger side and call it a day?

 

[broncodriver99]

I think you are fretting fractions of an inch on a vehicle that had tolerances of 1/2". Steve's chart could be from factory drawings or a combination of measurements taken from one or many Broncos. These are not precision made vehicles. I say get it to where you are happy enough with it.

 

[savage]

How old are these rigs, and how accurate were they put to gather at the factory. If you read post and threads it seems like a lot of bronco's of the same year have difference's between each, from age and other things, I think you can overthink it to death, I know, I WAS THEIR;D

 

[viking71]

Ha-ha thanks for talking me off the cliff guys. I'm a contractor and I guess I'm trying to apply custom cabinet type precision to this.