Probably pretty preposterous van project

[moparman76_69]

Yesterday I crossed a hurdle:



Still a long way to go though.

[moparman76_69]

Guts of the PTU:
pulled apart the ptu to see if the speed sensor gear was still machined in on the 93 PTU. It isn't, but I thought others might want to see the guts.

The end cover pulls off. There is a ball bearing in the cover and another bearing on the tube that drives the ring gear.



After the cover is off:



The shaft and ring gear.



The case after the gear is pulled out.



I didn't bother pulling the pinion gear (in this case the output) but it has a housing that pulls off also. The PTU takes gear oil. There is a large plug on the side that faces the block, and a smaller plug in the end cover that is the fill plug.

[Reaper1]

I love the smell of burn gear oil in the morning! MMMmmmmm!

[moparman76_69]

The lack of updates this time is for a good reason. I was too busy working on it to stop and post about it.

Week before last I tore apart the 93 AWD k frame and got the manual rack attached. Had some help last Friday and got it in. I had to elongate one of the mounting holes so the bolt would thread in correctly into the k frame.



I had to trim the piece that slides onto the steering column to get everything to play nice. I also had to ditch the plastic boot and trim the plastic shield around the base of the column. Sorry no pics there.

I ordered the rest of the parts to go ahead and rebuild the front end while it was all apart. I already had polybushings for the control arms.

First I removed the old ones.



Then I reassembled everything, rented a ball joint press and got it all together yesterday and today after work.

Driver's side



Passenger's side



Found out my engine alignment was off. I had tacked the pass. side mount in place, and thought I might have to correct it. I then determined I hacked up the mount too bad before, and need to get another one to hack up before I can finish the passenger side mount. I did tack it together so the engine can sit in unsupported. I started to mock up the header and turbo before calling it a night.

[turbovanman²]

Love that front mount setup,

[Ondonti]

Ok so how to make a AWD diff fit your 523. I'm sure the process is similar for a 520 but I can't confirm this.

First let me start by saying this was much easier than I expected. I assumed this would be one of the harder parts of the project but it was all pretty much straightforward.

Here are the two diffs side by side.



The 523 is on the left and the AWD is on the right. Here is more detail on the pass. side bearing.



The AWD uses a different bearing because the diff housing is larger and is splined to accommodate the PTU. Here is a better shot of just the AWD diff.



You need to use the pass. side bearing housing off of the 41AE the diff came out of so that A) the bearing will fit and B) the PTU will bolt up.



As you can see the top right bolt that the extension housing uses will line up, the others need to be drilled and tapped for M8x1.25 threads. Be careful as you will drill through the upper diff housing bolt hole with the top left, and each one of the lower holes will drill through the lower diff housing bolt hole. You'll have to use shorter bolts than what the extension housing uses. Remember that the case is aluminum so it will strip out easily.



One that is done all you need to do is put the 523 ring gear on the AWD diff. To do this you will need to flip the gear over and mount it to the opposite side of the diff than the stock AWD ring gear uses.

I unfortunately don't have many pictures of this but I'll explain as best as possible. The 523 ring gear's flange is offset. The "inside" of the ring gear flange usually bolts to the drivers side of the diff flange, the ring gear is threaded. The AWD diff and ring gear have a different offset so they won't readily interchange. If you flip the 523 ring gear and bolt the "inside" flange that originally mated to the drivers side, onto the passenger side of the AWD diff, this will get you almost perfectly back to the stock ring gear location.

If you mount the diff in the trans this way you'll notice two things, first is the ring gear doesn't sit exactly where it did with the original diff. I made a mark on the case before removing the diff, and again with the ring gear bolted to the AWD diff and it was "around" .035 off. I say "around" because others measured it as .030 and I was using a rather unscientific method (dial calipers and two sharpie lines). I decided to go with .030 as I figured that other people probably did a less ghetto measuring job and if it was a couple thousandths off it wouldn't wear the gear too badly. I ended up finding a transmission shop that took care of the machining, and in my excitement to remount the ring gear I didn't take pics of the machined surface. Put loctite on the bolts and torque them to spec, and you'll end up with this



The other thing you'll notice is that the ring gear bolt heads, which now stick out the drivers side of the diff, hit the gear that slightly protrudes into the pinion area. The only answer is to remove enough material off the bolt heads to clear. I haven't done this step yet but it is pretty straightforward.

After the diff is in then you can bolt the diff housing and etc. back up.

REMEMBER, this is just a guide, YMMV. I accept no responsibility for what you do to your vehicle.

I never saw mention here of the Driver side bearing etc. Carlos had to machine driver housing to accept the larger race. I also didn't see any mention of shimming.

[zin]

Carlos was using a 568,if that makes a difference...

Mike

- - - Updated - - -

Carlos was using a 568,if that makes a difference...

Mike

[Reaper1]

It shouldn't. The 568 uses the same diff bearing sizes as the 523 and 543. If I'm not mistaken those are also the same size as 520's and 555's. I *think* it's the same as the non-Neon 413's and probably earlier A670's.

[Ondonti]

All my AWD diff's have large bearings on both sides. My a543's (identical to a523) have small bearings on both sides of the diff.
It looks like you could turn down the diff to fit the smaller bearing but larger bearing seems like it would help something? Not sure why they upgraded it.

[moparman76_69]

The drivers side bearing on my PTU was the same size as the 523 diff bearing. Both the bearings on the 523 diff were the same, the passenger one on the AWD diff (in my case a 93) was larger.

[Ondonti]

The drivers side bearing on my PTU was the same size as the 523 diff bearing. Both the bearings on the 523 diff were the same, the passenger one on the AWD diff (in my case a 93) was larger.

This is still confusing. You mean the driver side bearing on your 1993 AWD diff was the same size as an a523 diff bearing, a small bearing. I find this odd because I own 2 AWD diffs and they both have large bearings on driver and passenger side. Also, Carlos' AWD diff has large bearings on both sides. It is possible my diffs are both from 1991 and 1992 and something different happened in 1993.........or later years? The AWD diff has more meat on it and would not fit a small bearing without being turned down. I also find this off if possible that they went all large bearing at first, then went to one small bearing, and then back to all large bearing.

[Vigo]

Well something odd definitely happened because there is a pic in the section you quoted that clearly shows the drivers side bearing on the AWD diff being the smaller size.

[Ondonti]

The picture of his Diff also has 8 braces, where the 5 speed diff has 6 braces on the driver side.
The two that I own are obviously large driver bearing.

[Reaper1]

After looking at the pictures and counting the rollers in the bearings, the pictured AWD diff the Brent quoted above definitely has the smaller bearing on the driver's side. It really looks to me like the diff was turned down to accept the smaller bearing because there looks to be grease on the bearing where the inner race would be pressed onto the diff carrier. That is a pretty standard technique for pressing on a bearing.

The larger bearings would be used because of the expected higher loads that the AWD will exert on the diff carrier and the case. I personally think it's a good move, and if it is at all possible to use the larger bearings, I would.

[moparman76_69]

This picture:



is the AWD diff driver side taken after I assembled it with the 523 ring gear. There are no modifications done to the diff itself. The ring gear is off the 523 diff and is a 94 unit, the diff is out of a 93 caravan AWD.

[Vigo]

I can definitely see the bigger bearing Brent is talking about. Unfortunately that's going to require machine work one way or another.

[Reaper1]

Yeah...something isn't right.

[Vigo]

I suppose id prefer to machine the bearing support that bolts into the case, because that way if for some reason it gets screwed up, it'd be a lot easier to replace than the diff housing itself.

[Ondonti]

This picture:



is the AWD diff driver side taken after I assembled it with the 523 ring gear. There are no modifications done to the diff itself. The ring gear is off the 523 diff and is a 94 unit, the diff is out of a 93 caravan AWD.

Well then is 1993 a year that a change was made in the build of these AWD transmissions or what? Either 1993 is the year to get a diff from or there is something Odd about the transmission you sourced parts from.
Having a factory freak diff would make these things easier.

[DetroitTurbo]

I just wanted to say, this build is sick and I hope I can see it some year at SDAC!