Build Stretched 1-Ton FJ40

[Firemedic831]

Mike could you do me a favor Next time you are laying under there could you measure from the front of your bellhousing to the rear of the atlas on the pass side ? I am not so worried about the center But pass side i have my rear link if that makes sence I know you have the 4 speed

 

[Mike Shull]

Mike could you do me a favor Next time you are laying under there could you measure from the front of your bellhousing to the rear of the atlas on the pass side ? I am not so worried about the center But pass side i have my rear link if that makes sence I know you have the 4 speed

No problem at all. It is roughly 38”.

 

[Firemedic831]

Thank you

 

[Firemedic831]

Just measured my TH400 with Orion is 38 inches

 

[Firemedic831]

So worst case scenario i could run the sm465 with a Atlas 4 speed and everything would still fit but not gain any clearance to pull my engine back . It would definitely work with a 2 speed hmmm

 

[Mike Shull]

So worst case scenario i could run the sm465 with a Atlas 4 speed and everything would still fit but not gain any clearance to pull my engine back . It would definitely work with a 2 speed hmmm

I’m pretty bias in this area so I am not going to advise you to get an Atlas 4.

 

[cruzinfj1]

Just watched your video. I'm betting that your vibration is coming from the slip in the driveshaft itself. How far does that stuff when you flex it? Looks like the front shaft is too short from the block to the pinion.

 

[Mike Shull]

Just watched your video. I'm betting that your vibration is coming from the slip in the driveshaft itself. How far does that stuff when you flex it? Looks like the front shaft is too short from the block to the pinion.

I’ve been meaning to call Tom Woods about that. I don’t know how much of the splines are left but it doesn’t move in or out very far when I flex.

 

[cruzinfj1]

Really hard to guesstimate by the pic, but that looks about 3" of blue sticking out? Betting if you lengthen that so you have an inch or inch and a half it would be night and day difference.

 

[Mike Shull]

Really hard to guesstimate by the pic, but that looks about 3" of blue sticking out? Betting if you lengthen that so you have an inch or inch and a half it would be night and day difference.

Good eye! That is 3” of spline sticking out. It is a 6” long travel slip spline so I’m thinking that it is okay.

 

[cruzinfj1]

I would give Tom Woods a call on it. That blue teflon coating is there not only for slip, but to take some of the "slop" out of it and tighten it up. In my experiences, the less exposed spline you have, the truer it stays.

 

[Mike Shull]

Something didn’t look right with my front driveshaft angles so I diagrammed them. My front driveshaft angles are not opposing to each other. These are straight u-joints (no cardan joint in the front).

 

[Mike Shull]

Something didn’t look right with my front driveshaft angles so I diagrammed them. My front driveshaft angles are not opposing to each other. These are straight u-joints (no cardan joint in the front).

View attachment 3770190

Shawn Wood replied and advised to reduce my angle at the transfer case first, then work my way from there. He also confirmed that I should not have as much spline showing on the front shaft and I will be sending it back to have it lengthened. I’m pretty sure that length is my error.

 

[cruzinfj1]

Shawn Woods replied and advised to reduce my angle at the transfer case first, then work my way from there. He also confirmed that I should not have as much spline showing on the front shaft and I will be sending it back to have it lengthened. I’m pretty sure that length is my error.

So as I run this thru my head, the angle from Tcase to carrier bearing shouldnt be giving you any vibration. That pillow block is mounted solid and the ujoints don't know the difference- thats what they do. In your overhead pic, what's the angle of the driveshaft from the pinion to block yoke on the frame? Raising that block is gonna mess with the angle to the front yoke, which is what you're trying to equal out. Not sure thats the answer. "Clocking it" may be the better way, IF you have to go back into it that far. I still think your problem is in the slip itself. I'm not arguing with what Woods said, but I guess if it were me, I would have them lengthen it first.

I've got a very similar situtation going on, and Ive sat and stared, drawn, measured, cussed, and started measuring again here.... lol

 

[Mike Shull]

So as I run this thru my head, the angle from Tcase to carrier bearing shouldnt be giving you any vibration. That pillow block is mounted solid and the ujoints don't know the difference- thats what they do. In your overhead pic, what's the angle of the driveshaft from the pinion to block yoke on the frame? Raising that block is gonna mess with the angle to the front yoke, which is what you're trying to equal out. Not sure thats the answer. "Clocking it" may be the better way, IF you have to go back into it that far. I still think your problem is in the slip itself. I'm not arguing with what Woods said, but I guess if it were me, I would have them lengthen it first.

I've got a very similar situtation going on, and Ive sat and stared, drawn, measured, cussed, and started measuring again here.... lol

I agree with you though the entire setup is not right. As I look back through my pictures I initially had my transfer case mounted lower, which leads me to think that at one point I knew that it needed to be that way.

The thing is that even though the joint at the transfer case measures 17°, that joint is very hard to turn by hand, and it gets stuck during rotation. It should have 3° more to spare, but it doesn’t and I always knew that it would be a problem. I just didn’t catch it soon enough.

The way I see it I should wait to lengthen the front shaft until I lower the transfer case and reposition the carrier bearing, which is necessary even if I am not changing the height as it will at least need to be angled differently to match the new position of the transfer case. All of that could change the length of the front driveshaft so it makes sense to wait.

On the bright side, I just hit 515 miles, so it’s time to change the gearbox fluids, plus I have a pretty bad leak at the inspection cover of the transfer case, so it’s a good time to check everything over.

 

[cruzinfj1]

I agree with you though the entire setup is not right. As I look back through my pictures I initially had my transfer case mounted lower, which leads me to think that at one point I knew that it needed to be that way.

The thing is that even though the joint at the transfer case measures 17°, that joint is very hard to turn by hand, and it gets stuck during rotation. It should have 3° more to spare, but it doesn’t and I always knew that it would be a problem. I just didn’t catch it soon enough.

The way I see it I should wait to lengthen the front shaft until I lower the transfer case and reposition the carrier bearing, which is necessary even if I am not changing the height as it will at least need to be angled differently to match the new position of the transfer case. All of that could change the length of the front driveshaft so it makes sense to wait.

On the bright side, I just hit 515 miles, so it’s time to change the gearbox fluids, plus I have a pretty bad leak at the inspection cover of the transfer case, so it’s a good time to check everything over.

Just outta curiosty, did you try giving the caps a little love tap with a ball peen on that tight joint? Sometimes that helps work it back to center if one was tight when you put it together.

Definitely post the update when you change it around.

 

[Ditcherman]

Something didn’t look right with my front driveshaft angles so I diagrammed them. My front driveshaft angles are not opposing to each other. These are straight u-joints (no cardan joint in the front). Have a look and let me know your thoughts but I’m sure that the carrier bearing needs to be raised.

View attachment 3770190

Curious why you don’t use a double cardon at the transfer case flange? That may also save you form sending a shaft off to be lengthened.

My plan is to have a short shaft off the transfer case then a double cardon off that towards the front….i think.

 

[cruzinfj1]

Curious why you don’t use a double cardon at the transfer case flange? That may also save you form sending a shaft off to be lengthened.

My plan is to have a short shaft off the transfer case then a double cardon off that towards the front….i think.

So Im working thru a very similar scenario, and am curious why you would do the cardon at all. I know the tcase will move around a little bit, but the carrier block is welded on the frame. Why a cardon at the case? This type of set up, we shouldnt need a cardon at all, right? Or am I missing something?? Not trying to argue or hi Jack, trying to figure it out too...

 

[Mike Shull]

I’ve used a double cardan joint when I’ve had drive shaft angles on either end that vary drastically (i.e one end has a 5° angle and the other end has a 10° angle) and a vibration was present. I put one on my rear as a precaution as my rear pinion angle is at 0° and the transfer case is roughly 3-5°. The two joints inside of the double cardan joint work together to balance out vibrations.

My flange and joint in the front of the transfer case are not high angle specs, and the working range is 18-20°. I can see the joint bottoming out on the flange as it rotates. Shawn Wood said that in theory a double cardan would fix this bottoming out problem, though he also said from experience that running a double cardan joint typically wouldn’t be possible with a two piece driveshaft. He didn’t explain why.

There are all sorts of options on the market for high angle joints, both in single and double joint configurations, but all of that costs money and Shawn advised me to decrease the transfer case angle. It won’t cost me anything except time to clock my transfer case.

 

[peesalot]

If the tcase moves a little and the frame flexes the shaft coming out of carrier bearing will not be pointed at tcase flange, unless that carrier bearing rotates/pivots/articulates, this set up is not right and that tube will separate from the tcase side of the woodlee part. IMO.