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Engine moving brain storm


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Put 12" concrete blocks in front of the front wheels, had my daughter get in, start it and put it in gear. I then crawled underneath to look at the drive shaft yoke and transfer case while she slowly pushed the gas deeper and deeper. Engine/transmission/transfer case move forward with the drive shaft. Drive shaft is 2" away from bottoming out.

 

So new theory:

Slip yoke is out far enough to have enough play that under load and with the steep tube angle it can jam itself with enough friction to not want to slide into the transfer case more. Trying by hand the yoke has about 1/32" of play.

 

So possible solutions:

1 - Chain engine to make it impossible to slide forward. This may or may nor cause problems out back.

2 - Put together a set of leaf packs with less lift (I'm currently sitting at about 8" in the back). May or may not work.

3 - Shim the sping perches to move the pinion angle up. Should give a bit more engagement in return for possible vibes.

4 - Longer yoke off Ebay.

5 - Longer drive shaft

6 - SYE and new drive shaft.

 

I think I'm going to go with 1 and possibly 3 as a temporary band aid until I have the funds to do 6. Most expensive solution, but probably the best, with added benefits.

 

So what drive shaft would be a good candidate to start out with as a base to use with SYE and an 8.25"?

 

What are the thoughts on agricultural PTO drive shafts? They seem to be popular with guys building demo derby cars and trucks.

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A quick solution is to drill the another center pin hole in your spring perches, rearward of the center one you're using now.

(measure carefully, so both sides match)

 

Move the axle forward to the new hole, drill the top plate to accept the top (nut side) of the center pin in it's new location, and bolt everything back together.

 

You can move the axle forward 3/4"-~2.5" this way (depending on how long your perches are).

 

Also works to move the axle rearward.

I drill multiple pin holes in the perches for every axle swap I do, right now my SWB MJ's axle is set back about 1.5".

 

This D60 rear's been that way (in 2 different MJ's) since 1998.

I had a slightly short driveshaft made for the original D35 (when I did the original 4x4 swap in 97), so I moved the 35 forward.

When I put the 60 in (much longer pinion), I used the same trick to move it back, and keep the same driveshaft.

 

Over the 11-12 years, I've had zero problems whatsoever with this mod.

 

Of course you'd have to trim the ft edge of your flares/wheelwells, depending on how far you moved it.

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PS,

FWIW, this is more than just a little bit nuts.

Put 12" concrete blocks in front of the front wheels, had my daughter get in, start it and put it in gear. I then crawled underneath to look at the drive shaft yoke and transfer case while she slowly pushed the gas deeper and deeper.
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I believe you can get a yolk out of a YJ that is longer, not sure what years. Probally only be a few bucks at the JY.

What you gain in length you loose in spline engagement. So it's really a wash and not worth it as it actually does not do anything to make it longer.

 

I've found this to be true too.

 

YJ yoke 'was' longer, but splines inside were recessed from edge.

 

YJ yoke did allow more joint angle, but (atleast the one I had) didn't allow any more spline engagement.

 

FWIW, an XJ yoke can be ground, to allow the same joint angle as the YJ yoke, if you need more shaft droop.

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The perches came with 3 sets of holes already in them, and the axle is already 1" forward from center. As for being nuts to get under the truck while the engine was running in drive? Not really. I trusted my daughter to hit the brake and turn the key off if I had to yell at her to do so, but fully expected a rear tire to start spinning and digging a hole in my gravel driveway before it would climb the blocks, and with the 33" tires the axle would have gone right over top of me without hitting me. If I didn't fully trust the lack of traction on the gavel I would have parked it in the grass up against my tree. But I was able to tell what was happening before the tire even spun.

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I believe you can get a yolk out of a YJ that is longer, not sure what years. Probally only be a few bucks at the JY.

What you gain in length you loose in spline engagement. So it's really a wash and not worth it as it actually does not do anything to make it longer.

 

I've found this to be true too.

 

YJ yoke 'was' longer, but splines inside were recessed from edge.

 

YJ yoke did allow more joint angle, but (atleast the one I had) didn't allow any more spline engagement.

 

FWIW, an XJ yoke can be ground, to allow the same joint angle as the YJ yoke, if you need more shaft droop.

 

 

More bogus information above...

 

Both of my '94 YJ yokes have full length splines. The yoke is 1/2" longer and allows for a large increase in axle droop before binding. The splines are the same length as a MJ yoke. Since the splines are full length you gain 1/2" of engagement.

 

Just don't buy an aftermarket yoke one because some don't have full length splines.

 

I would check out the bushing in the transfercase output housing for wear. You can see how far out my YJ yoke was out of the transfercase, It ran a 15 degree constant operating angle on both u-joints on my XJ and vibration was never a problem. My maximum operating angle at full droop was 24 degrees.

I put 50,000 miles on without even wearing out a u-joint or having vibration issues.

 

Be sure to put some transmission assembly grease in the yoke to keep it from binding up before it starts to slide.

 

 

A real YJ yoke.

 

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A cheep aftermarket imitation without full length splines.

 

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MJ yoke compared to a YJ yoke.

 

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The YJ yoke binds at 28 degrees of angle. A MJ yoke binds at 14 degrees of angle. You will distroy a MJ yoke trying to get 28 degrees of angle out of it.

 

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These GM TH-350 27-spline 7" long yokes work well on our NP cases and AW4 trannys. Splined the whole length of the shaft, and can be cut to length. Grinding may be required for large pinion angle applications. :cheers:

 

!BN74VD!!mk~$(KGrHgoH-EYEjlLly8E)BJsJRny(E!~~_1.JPG

 

 

It can't be ground enough to get the same operating angle a YJ yoke has. You would distroy that yoke or a stock MJ yoke before it can flex to the same angle.

 

Just look at this picture to see why...

 

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It can't be ground enough to get the same operating angle a YJ yoke has. You would distroy that yoke or a stock MJ yoke before it can flex to the same angle.

 

Don't have to look at the pic to see why; I understand this extended yoke has it's limitations on the operating angle even if grinded. But if your goal is just need to extend your driveshaft length with an op angle of maybe 12-14 degrees or less, this yoke will work just fine. BTW, the max recommended op angle for the 1310 Spicer joint is 12 degrees. This is not to say they will not function for awhile if the angle is greater as in your case, it's just Spicer's recommendation. :D

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It can't be ground enough to get the same operating angle a YJ yoke has. You would distroy that yoke or a stock MJ yoke before it can flex to the same angle.

 

Don't have to look at the pic to see why; I understand this extended yoke has it's limitations on the operating angle even if grinded. But if your goal is just need to extend your driveshaft length with an op angle of maybe 12-14 degrees or less, this yoke will work just fine. BTW, the max recommended op angle for the 1310 Spicer joint is 12 degrees. This is not to say they will not function for awhile if the angle is greater as in your case, it's just Spicer's recommendation. :D

 

 

Spicer reccomends that as the optimum angle. They rate 30 degrees as the maximum angle. After 12 dergrees they say the lifespan is reduced, but 50,000 miles without any play in the u-joint is ok by me. :yes:

 

10" of lift on a MJ will bind the stock yoke at droop and is 11 degrees of constant operating angle on a short box stick shift 4.0 model would be just fine with a YJ yoke.

 

It would work just fine.

 

:cheers:

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I've found this to be true too.

 

YJ yoke 'was' longer, but splines inside were recessed from edge.

 

YJ yoke did allow more joint angle, but (atleast the one I had) didn't allow any more spline engagement.

 

FWIW, an XJ yoke can be ground, to allow the same joint angle as the YJ yoke, if you need more shaft droop.

 

 

More bogus information above...

 

Both of my '94 YJ yokes have full length splines. The yoke is 1/2" longer and allows for a large increase in axle droop before binding. The splines are the same length as a MJ yoke. Since the splines are full length you gain 1/2" of engagement.

 

Just don't buy an aftermarket yoke one because some don't have full length splines.

 

 

What do you mean BOGUS INFORMATION

Have you been digging through the 20 years of Jeep parts in my basement?

 

What would you like to know about the YJ yokes I have?

 

I bought the first one from 'American Metal' in 1994.

American Metal was an XJ specific lift manufacturer that rose from the ashes of Golden Desert Mercantile, around 93/94.

They're long gone now, but you could get a custom 6.5" lift from them in 1995.

The owner, Mike's black XJ, on old style Goodyear MT's was the first XJ I ever saw on 35's. That was in 1995. (on the above mentioned 6.5" lift).

Also the first I read about on ft & rear 44's, with 4.88's.

 

My memory is pretty good from back then, especially when I was spending money.

 

I bought LCA's & that YJ yoke from Mike.

Was it aftermarket? I have no idea.

it was brand new, he sold it as a YJ yoke, and I believed him.

It was longer than my XJ yoke, it allowed more droop, AND the splines DID NOT extend all the way to the end of the body.

I measured them, and it worked out to EXACTLY the same spline engagement as the XJ yoke I removed.

I know all this is true, especially since I ground down the XJ yoke, and used that with the spare driveshaft I used to carry.

Once it was ground down, it was for all purposes exactly the same as the YJ yoke I had bought.

 

The second one came from a bent 87' YJ I bought in 1997.

The t-case was broken in half, but the yoke was fine, so I saved it.

Was that aftermarket, or replaced sometime in the 10 years before I bought it, I have no idea.

The yoke from that was a different casting from the 'American Metal' yoke, but it's splines were also not any longer than the XJ & later YJ yoke's I was already using.

I know this, because I compared them, but did not bother to swap the ground down XJ yoke for this 'new' YJ yoke.

 

The next year (1998), I bought the ft axle & T-case out of a 1995 YJ.

I used the disconnect style 297 shafts in my MJ's axle, and, since it had 4.10's, I used the open carrier for my 4.65 gear swap.

That third YJ yoke was a squared off casting exactly like the one I bought from American Metal (later style), and it's splines also did not extended all the way to the end.

 

That one went onto the driveshaft I had shortened for the MJ.

 

If I feel like it I'll snap some pics of all the bogus yokes I have kicking around here, and you can tell me how I'm making this all up, and/or casting them in my basement.

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I bought mine directly from the dealership for a 94 Jeep YJ and all three I bought had full length splines. I bought part# 83502855 which was used on YJ's from 87-96. I just double checked all those years in the Jeep parts catalog to be sure.

 

The only ones I have ever seen without full length splines were aftermarket ones sold as YJ yokes of extended travel XJ yokes.

 

I was also a Mopar tech for 15 years and never seen a YJ yoke that wasn't fully splined.

 

I have had probably over 100 rear driveshafts out of YJ's as a tech over the years.

 

This is where I got my information from.

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Here's the first two shafts out of the 'pile' (yeah, it's a mess down there).

 

 

On left is YJ yoke on an XJ driveshaft (87 4.0L 5spd shaft).

 

On right is XJ yoke, on XJ driveshaft (85 2.5L/auto shaft)

 

Both unclearanced & stock as far as I know.

 

Inside of XJ yoke (splined right to the end):

 

Inside of YJ yoke (not even close to the end):

 

It's possible that this is an aftermarket part, but atleast 3 of the 4 YJ yokes I have came off of stripped YJ's (I forgot to include the 4th YJ yoke off of the 92 Renegade that donated the engine currently in my MJ in my last post).

 

I'd be shocked if every one of these yokes was replaced at sometime with aftermarket parts.

 

I don't mean to sound p!ssed,

but putting a huge "bogus information above" at the top of your post isn't the best way to disagree with someone who may have had different experiences, and come to different conclusions than your own.

 

I can tell you for a fact that the castings changed over the production run of YJ's, so even if they use a newer, superceded part number for earlier years, that doesn't mean the same part was used for the whole run.

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I bought mine directly from the dealership for a 94 Jeep YJ and all three I bought had full length splines. I bought part# 83502855 which was used on YJ's from 87-96. I just double checked all those years in the Jeep parts catalog to be sure.

 

My 87/88 book shows two numbers, the 83502855 & 83503114.

 

 

Maybe one was for the earlier 207 case (IDK).

Either way, earlier YJ yokes I have pulled off were more rounded, like the XJ yoke I posted (but with a deeper throat), and later ones were squared off.

 

If I can find the other's, I'll post pics, and I'll snap a couple of the ground down XJ yoke if any of them are still around.

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I bought mine directly from the dealership for a 94 Jeep YJ and all three I bought had full length splines. I bought part# 83502855 which was used on YJ's from 87-96. I just double checked all those years in the Jeep parts catalog to be sure.

 

My 87/88 book shows two numbers, the 83502855 & 83503114.

 

 

Maybe one was for the earlier 207 case (IDK).

Either way, earlier YJ yokes I have pulled off were more rounded, like the XJ yoke I posted (but with a deeper throat), and later ones were squared off.

 

If I can find the other's, I'll post pics, and I'll snap a couple of the ground down XJ yoke if any of them are still around.

 

 

I was going off of my first hand infomation I have. I still say a XJ joint yoke can't be ground to get the same clearance as a YJ yoke has.

 

On the left is a new Jeep XJ yoke bought from the dealer I worked at. On the right is the '94 YJ yoke bought from the same dealer.

Image Not Found

 

To get the same angle before binding the XJ yoke would be ground into the machined sllip part of the yoke. This was why I say bogus, just look at the throat lengths.

 

I have never seen a factory yoke thay wasn't fully splined.

 

I may be wrong, but I know the yoke you have pictured looks just like the aftermarket ones I have seen. It could be a leftover from the AMC vintage. You never know about their parts... The operating angle is still higher on a aftermarket yoke even with the spline loss. So no it isn't a wash.

 

Sorry if I offended you the bogus comment was meant for LEAD_NOT_FOLLOW's comment that it was a wash.

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