drive shaft lenght ?

[wannabeMJ]

finaly getting time and money to do this .......

 

I need to shorten my D-shaft

from this:

lwb,_2.8,____ax5-ax4,______np207,____d35= 54.75"

to:

lwb,_4.0,____ax15-ba10/5,__np231,___d35= 50"

 

and I have a 4.5" lift

from what I read, it should be an inch longer then the 50" indicated above

so shorten to 51"

right???

[ComancheKid45]

From what i understand Yes, that would be correct.

[JACKED88]

Depends on if and how heavily you load your truck bed. For that reason I wouldn't go 1 inch longer than stock. 1/2" maybe but not a full inch. With a loaded bed your truck will be getting closer to stock height. As such if your shaft is 1 inch longer than stock and you hit a dip or whatever in the road causing the rear to squat down even more your likely to over extend the drive shaft and damage the trans/tc. Better to have it 1/2" short than 1/2" too long.

 

So your not taking the word of just one person, I'm pretty sure some of the other guys here will agree.

[Pete M]

because of all the variables (pinion angles, type of lift, etc), the best thing to do is still to put the yoke back in the tcase where it was at ride height, then measure to the yoke on the axle, center of u-joint to center of u-joint.

[wannabeMJ]

so from what I read here I should call the guy and get it done at 50'' 1/2 and not 51'' ??? :dunno:

 

anyone running HC 4,5'' kit here ??

[JACKED88]

so from what I read here I should call the guy and get it done at 50'' 1/2 and not 51'' ??? :dunno:

 

anyone running HC 4,5'' kit here ??

I can't tell you what to do. To do it right you should do what Pete said. Otherwise its just a guess.

 

With that said, I still don't think 4.5" of lift is enough to warrant a full inch of additional shaft length.

You could actually run a stock length shaft. Yes, due to your lift it would be a little short but depending on how you drive your truck it would work fine.

 

Do it right. Go get your yoke from the shaft shop, stick it in your t/c to where you can tell its been riding on the seal and measure from center of u-joint to center of u-joint like Pete said. (+/- 1/8" is close enough)

 

Who knows, you might end up with a measurement thats an inch over stock but wouldn't it be better knowing its right instead of guessing?

[Pete M]

we had one guy recently that, for reasons that still escape me, found his driveshaft too short after a lift. :ack:

[wannabeMJ]

after mesurement I have to go with 50'' +/-

 

I was using the wrong yoke the original comanche instead of the cherokee's (chero drive train)

 

so wasn't going in all the way so found the good one then I mesured

 

real close to original lenght ( what it should be with the set-up)

 

so ill call the guy first thing monday thx all for the answer

[JACKED88]

I was using the wrong yoke the original comanche instead of the cherokee's (chero drive train)

so ill call the guy first thing monday thx all for the answer

If thats true you've taught me something. I didnt know XJ's and MJ's used different yokes.

 

Before sending this I did some research on XJ and MJ rear yokes and found then to have different part numbers. I'm not sure but the difference may be 2 and 4 wheel drive specific. I believe the slip part to be the same and its the u-joint yoke itself thats different. I think the difference between um is the amount of u-joint clearance and or how much shaft angle can be achieved without the shaft binding in the bottom of the u-joint cradle.

I'd have to do more research (or ask somebody who knows ...... hint, hint) to know for sure what the difference is.

 

Anybody???

[Pete M]

I don't think it's an XJ/MJ difference as much as an 86 vs later model difference or 2wd vs 4wd.

 

I remember that I couldn't use my 2wd 88 yoke with my 4wd 99 t-case. Been a while, but I think it was a spline count difference. :dunno:

[JACKED88]

I don't think it's an XJ/MJ difference as much as an 86 vs later model difference or 2wd vs 4wd.

 

I remember that I couldn't use my 2wd 88 yoke with my 4wd 99 t-case. Been a while, but I think it was a spline count difference. :dunno:

Agreed. I think they changed the spline count in 93. I'm talking about earlier yokes. 86-92 According to the shop thats gonna cut my shaft, Jeep used 2 yokes. A standard angle and a high angle. The slip part of the yokes are the same. The difference between them is what I was saying about one (the high angle) having a deeper u-joint cradle allowing for more shaft angle. The high angle yoke was primarily used on CJ models due to their short wheel base and even shorter drive shafts.

[wannabeMJ]

I don't think it's an XJ/MJ difference as much as an 86 vs later model difference or 2wd vs 4wd.

 

I remember that I couldn't use my 2wd 88 yoke with my 4wd 99 t-case. Been a while, but I think it was a spline count difference. :dunno:

Agreed. I think they changed the spline count in 93. I'm talking about earlier yokes. 86-92 According to the shop thats gonna cut my shaft, Jeep used 2 yokes. A standard angle and a high angle. The slip part of the yokes are the same. The difference between them is what I was saying about one (the high angle) having a deeper u-joint cradle allowing for more shaft angle. The high angle yoke was primarily used on CJ models due to their short wheel base and even shorter drive shafts.

 

 

to answer your questions about the spline count they are the same

dunno if the slip part of the yoke is bigger but it only seem to go in about a 1/4'' compare to the xj one

dunno either about 2wd the comanche was already 4wd wight just be a difference between a 207 and a 231

I tought they were all the same ( 207, 231, 242, 231J )

there just might be a lot more that I don't know about t-cases then i tought

 

final lenght of the d-shaft is 50'' 1/4

fits like a charm

 

 

on further note : what would make a yoke able to allow more angle then an other ??

would it be the depth of the yoke itself ( the distance between the close part of the joint and the slip part)