Drive Train Alignment

Last night while installing my rear drive shaft, I noticed that the rear of my t-case is offset from the pumpkin about 3" to the pass side. This puts my d-shaft running at an angle back to the pumpkin.

I've discussed this whole drive train alignment problem before. It's most noticeable at the shift cane where it comes through the floor. The shift cane sits about 1-1/2" to the right, and of course the farther to the rear we go, the worse it gets, resulting in a 3" offset @ the rear of the t-case.

I'm convinced that the only way I'm going to fix this is to pull the front clip off and cut the engine mounts loose from the frame and then line everything up and then re-weld the mounts back to the frame.

I might even have to sacrifice these mounts and replace them with new ones.

I expect it's been running like this for some 30 yrs now with no problems but it's driving me nuts.

Another problem with it is the clutch bellcrank. I have to shim the pivot off the frame a good 1" or better with washers. I might still have to shim it some, but if I could move the whole thing over it'd be alot less washers to flex and cause that bellcrank to pop off it's pivots.

Also, right now I've got the tranny crossmember shimmed down about 1" to keep the reverse light switch from hitting the tranny hump. Now the tranny hump is always going to be there, I know, but there is an offset or raised section in the tranny hump which I believe is for this reverse switch. It's doing me no good because the tranny and such is sitting to far to the pass side. I've got to move it over in order to get under that raised section of the tranny cover.

The other real benefit is that I can buy a new transmission shift lever boot and it won't get torn to pieces from the shift cane being way off center.

OK...opinions.

 

John Im not sure if the xmembers are the same but i got some good pics of mine if you need a ref. I have a hurrincan so im not sure if there the same or not . I be glad to send you picks of the xmember if it would help . Maybe some one with a V6 could help you out with checking the engine mounts

 

The crossmember looks like swiss cheese under there. Way too many holes.

I couldn't attest to the originality of the engine mounts but they look original.

I've had people tell me that I should just un-bolt the tranny from the x-member and push the tranny over and then re-bolt it, but there's no way that I can move it that far. With it bolted to the engine it just aint gonna move.

Honestly, I don't think this will be all that hard...am I missing something?

I'm thinking...remove the front clip which is no biggie.
Remove the crossmember - no biggie.
Cut the engine mounts loose @ the frame with maybe a grinder and cutting wheel
Shift everything over so it's straight from front to rear.
Then re-weld the mounts to the frame
Then re-install the x-member and drill new holes or maybe I could use some of the other holes.
Then re-install the front clip.

 

I don't think so Billy....it's been like this since I first got it and before, it was smooth as glass @ 70 and 3000 RPMs.

BTW...I test drove it last night with just the rear d-shaft in place and it seems smoother between 0 and 55 but I've still got the vibration @ 60 plus. So...I think you were right...I've got a wheel or two out of alignment.

 

Could the crossmember be mounted 180*?

If the crossmember was the problem, wouldn't the motor mounts be bound up, twisted. Wouldn't they wear out quick?

I would suspect the crossmember before the motor mounts unless they were wrong from the factory or Previous owner.

Get the tape measure out. I can get some measurements of my jeep this weekend if you want John.

 

I guess the crossmember could be in 180 degrees, but I don't think reversing it would help line up the drive train components. Basically without the crossmember in place the placement of the engine dictates what line the rest of the stuff is going to sit. Or at least I think it does. In other words, I've got everything bolted up and if I were to simply try to push the stuff over, it just won't go because it's bolted hard to the engine. The only way it's ever going to move is if the engine was free in the bay.

 

Do you have a broken or damaged mount, check carefully!!
If your mount on the engine (not the frame) was out just an 1/8" it would allow the tail of the transmission to move around a couple of inches. I bet the mounts on the frame are in the right place but that you have a damaged mount on the engine. John take a tape measure and measure from the front of the frame to the front of the mount welded to the frame, let that be the guide as to if the frame mounts are in the right place.

 

Yes...several times....it won't move...well actually it will move but not nearly enough. I've moved it over as much as I can and that's where it's bolted now, and it's still way out of alignment.

 

John with my front bumper off and using a tape measure and following the closest straight line over the radiator crossmember, it is 31" from the front edge of both mounts to the front edge of the side frame rails, that is with the tape measure laying right up against the edge of each frame rail!!!
If yours measures the same you have a problem somewhere else, don't cut the mounts.

 

I suppose it could be a combination of a shifted body and maybe axles shifted...remember my leaning spring hangars.

I have measured once before the distance from the inside of the fender well to the face of the tire on the rear of the jeep. I know that I have 1" difference @ the rear wheels.

 

The 4 cyclinder mounts are off set looking at mine . You think some one made a engine swap and didnt redo the mounts. Just throwing ideas in the air .

 

I considered it but the vin number confirms the jeep came with the V6.

I think they just welded the danged mounts in the wrong place. I've seen pics of the assembly lines from back then and there were no robots welding stuff in place.

 

Just measure them before cutting them and messing it up.
To be honest John our robots at work mess up more than the people do, its just that there 10X faster so they can justify the screw up. Back then they used jigs to line stuff up.

 

I'm not going to cut anything till I check and double check, it's just that I've already done quite a bit of that checking and double checking and there seems to be no other reason for the bad alignment.

Tim Harris and I have been talking a little bit behind the scenes and I've about decided that once I get my shop built where I can strow parts all over the place, that I'm going to tackle a complete body removal, where I can pull some strings and lign every thing back up...while I've got the body off, I'm going to fix a few floor boards.

I'll be down for quite a while cause I work slow, but I think it needs to be done....right down to the bent leaning crooked spring hangars.

 

John,

First thing that comes to my mind would be is the frame straight? Ladder type frames can be out of square simply from snowplowing (I know, not in MS ) It could also be from a minor offset collsion in the past. 1 inch difference (maybe as little as 1/2 inch) from one side of the frame (@ motomounts) to the other could translate into the 3" at the tail of the TC. That is about 60 inches of distance from motor mounts to tail of TC.

Your motormounts should be welded in the correct place but will travel with the frame rail if it moved from a collision.

Very hard to check with the body on. In the bodyshop we had a rod with pointers on each end to cross-measure 4 common body bolt points. At home, you could rig something up from the 4 middle body-to-frame mounts. Maybe 4 rods that dangle down below the trans and then cross measure with a tape. The 2 measurements should be equal. On a Jeep, they may have come from the factory unequal

Not a perfect method without the bodyshop measuring tools but may shed some light. Check the Factory service manual for cross measurements. It might be in there.

The swiss cheese cross member may indicate that someone in the past couldn't get the powertrain to bolt up right --so they compromised and made it work.

 

John,
I can tell you from my buildup that my rear driveshaft does go at an angle towards the pumpkin on my rear diff.I would say it's at least 2 inches. I never really noticed it before, until I had the body off the frame.
The other big factor to consider before moving the engine over towards the driver side, will be your steering and exhaust clearance.
Before I secure everything down oin my 4.3 swap, I measured from my frame rail on the insdie to my oil pan rail on the engine, just to make sure everything was pretty well centered. I did this as just kind of a secondary check, before making everything permanent.