Transfer case regear diagram + install notes (WIP) (1 Viewer)

[lasoundguy]

Been staring at the FSM and the videos online trying to plan out the tc regear.
Do I have the right things highlighted? Doing both the 3.1 and the underdrive.

This is @cruiseroutfit 's great chart with me marking up the chart with some colors for reference in the diagram (green is changed for 10% UD, purple is for the 3.1 low range.)

Based on that I'm trying to make sure I highlight what's changing.

Idler gear -- the low gear changes out.

Center diff--High Speed Output Gear and Low Gear change (green is 10% UD, purple is 3.1 low range)

Input shaft: 33->31 for the 10% UD.

Also based on this I think I get why the gears compound (underdrive HR to low range) but it's only partially effective, i.e. the reduction in low range gearing is 33/31 ~6% as the additional 3.x% change you get from the high speed idler gear changing from 33-->34 teeth doesn't impact low range. Correct?

Thanks in advance.

 

[cruiseroutfit]

Looks right

I use the EPC diagram as it's imo a little clearer. Pardon my chicken scratches but here are the pairings:

Obivously the input gear (36212) drives the high speed output gear (36203) via the idler gear (36221) but the idler doesn't change.

So you will change 36212/36203 for the high range and 36224 and 36242 for the 3.1:1 low.

The high range kit requires no mods, just sent up the case per the FSM. The low range does require some minor trimming and you should have some instructions with the gear on that.

 

[lasoundguy]

OK, awesome--thanks for that. Appreciate the markup. We'll see if/when I have to start my "RTH" thread come this weekend.

 

[Road Apple]

Let us know how it goes. I’m looking at doing the same soon.

 

[Bama4door]

OK, awesome--thanks for that. Appreciate the markup. We'll see if/when I have to start my "RTH" thread come this weekend.

Any update on the install?

 

[lasoundguy]

In progress! I figured I'd post up a new thread detailing how it went for me once I finish...right now doing the press work.

 

[Bama4door]

In progress! I figured I'd post up a new thread detailing how it went for me once I finish...right now doing the press work.
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Awesome, looks like you’re organized! Maybe post it all in this thread to keep it all in one place? Would probably help a lot of other people (me) when doing an install too.

 

[Saddletramp]

@Cruddz.

 

[KTP]

Great Thread.
I too have bought the gears and getting ready to dig into this after i re-install my fresh re-built motor.
Thank you all for your input.

 

[lasoundguy]

OK, taking your advice and documenting in this thread.

Some notes from dropping the transfer case--most of the instructions advise you to leave the front housing in place and crack the case open with it on the truck...but most of the people who have done the job say drop the tc entirely. I decided to drop the case...so far, not regretting that decision. It wasn't as straightforward as I wanted it to be, but not too bad. Pulling the driveshafts was kind of annoying as I had to jack up each in order to rotate the shaft for access to the bolt plate, but only added maybe 20 minutes to the process once I realized what the issue was.

The electrical connectors on the transfer case are a bit challenging, mainly because they are bolted down in ways that aren't obvious at first glance (particularly two connections near the top of the case.)
Some pictures attached to help others.

 

[lasoundguy]

Continuing on, separating the cases was pretty straightforward. Saw a few drops of red tranny fluid on the shaft but plan on replacing the output seal anyway so I don't think it's a problem.

It was at this point I found one more electrical tie-down by the diff motor that I had to disconnect.

And success (called it a night after about three hours to drop the case...good thing I don't make a living wrenching, I'm slow!)

 

[lasoundguy]

OK, this morning (Sunday) I tackled pulling the case apart.
Started with this balancer, easy.

@OTRAMM suggests taking a picture of these electrical connectors so you know which goes where.

I couldn't figure out what size that nut was (my metric sets stops at 24mm) but they came out super easy with a crescent.

Next up was the motor housing, also still easy. The gear came out without issue as did the spring and ball (with a magnet.)

 

[lasoundguy]

I know I may be overdoing it with the pictures but hopefully it helps others.

Pulling out the ball after the spring came out.

Separating the rear housing was simple, I made a cardboard template for the bolts since they aren't all the same length.

Also wanted to document the shim order on the input shaft.

Now on to removing the bolts for the middle section of the housing ("rear case" vs "rear extension" in the FSM.)
This is also pretty straight ahead, only thing is I noticed two of the bolts had washers on them and the rest didn't so I took a note of it. Sorry for looking like a toddler wrote the word "Extra"--my sharpie had some oil on it lol.

Now remove the large snap ring on the input shaft and pull the case.

 

[lasoundguy]

And here is where I got stuck for over an hour as I couldn't get the input shaft to slip through the case the way it was supposed to. Finally after much cursing and playing with it I was able to pull the small snap ring and somehow that made it all fit through, even though I can't actually figure out how those parts relate. Thanks to @ArmyFJ for his help and suggestions.

With the shaft free it was time to press off the input gear. Hard to see but I used a bearing/seal driver from this kit which I had purchased when I rebuilt the knuckles.

And now pressing on the new input gear (part of the 10% underdrive, this goes from 33 tooth to 31--see first post.)

Then it was on to the idler shaft. This the bearing splitter I used, it seemed fine. I did end up using some sockets for pressing stuff out--15/16" and 13/16" seemed to be good sizes. They held up fine although I was concerned (I did use my 6 point versus 12, not sure it made the slightest difference.)

I lubricated the bearings and pressed on the new gear (idler low gear goes from 22 to 19 tooth.)

 

[lasoundguy]

Then it was on to the center differential. First, a note--I had made it three years without real impact tools (moved to the current house in 2017, still don't have 220V in the garage.) That ended here...I jury rigged a temp 220V circuit to get my compressor up as I just couldn't crack the center diff 14mm bolts--mainly because I couldn't figure out a safe way to hold the damn thing. Had I skipped ahead in @OTRAMM's video to the end, I would have used his technique to mount this up in the press for stability while breaking the bolts (he does it for torqueing them back in), but as it was...my 1/2" impact made short work of them. Damn, I had convinced myself that lithium ion impacts were good enough, but I was wrong.

OK, moving on as I try to explain why 50 minutes of OTRAMM's video took me a day and a half lol. There are two small pieces in the center diff--both referred to as "straight pins" in the FSM. They both fell out on me while disassembling so be careful. The smaller one is actually easier to keep track of, but this pin (circled in green below) fell out onto the bench without me realizing it at first.

On to the jaw pulling. I didn't really like this part, but it worked OK. I think if I have to do this again I'll try to figure out how to do more on my press and less with the two-jaw, but it did work OK. One note that seemed weird to me, for this step you attach the jaws to the clutch sleeve (hold it up against the high speed output gear while you clamp the puller.)

OTRAMM shows the next pull as the low gear taking the clutch hub and gear bushing with it, but that didn't seem to work for me--or at least, it might have, but after a short while the low gear was fully loose while the clutch hub was still on tight. I decided to do a third jaw pull from the clutch hub, which took the hub and the bushing off the shaft, at which point the low gear slips off the hub easily. YMMV, just sharing that three jaw pulls vs two seemed better to me.

This was the third pull.

 

[lasoundguy]

OK, on to reassembling the center diff. I put two placeholder bolts into the new low gear to keep it aligned on the spindle/hub thing ("differential front case" in FSM) and then pressed in the clutch hub. OTRAMM does this with a brass drift, he must have a magic touch as it didn't work for me. Didn't take much press pressure so hopefully all OK. I used two sleeves from this kit I bought (kinda more than I needed tbh, but with the current Covid19 situation I was trying to avoid hunting down random stuff at the hardware store as everything seems to involve waiting in line for a long time.)

With the clutch hub in place I could easily see the straight pin for aligning it to the gear bushing.

Then I used a laser level to make sure everything was aligned prior to pressing it in.

(Looking up from underneath I could see that the laser was hitting the slot for the straight pin in the bushing.)

And done (with the bushing and clutch sleeve.)

I don't have pictures of putting the new high speed output gear (33-->34 tooth for the underdrive) or the front drive gear piece in, but once the needle bearings were on the shaft they pressed in quite easily. OTRAMM's video was super helpful.

Now I flipped the diff over and reassembled the pinion gears, placed the longer straight pin in, and bolted the rear case back on.

 

[lasoundguy]

Last step for the day was torque'ing up the case bolts--it's a two stage thing (first 65 ft/lbs, then loosen, then 72 ft/lbs) and here is where I saw OTRAMM's trick of pressing the diff into place to hold it down while you torque. Worked pretty well.

OK, tomorrow I hope to clearance the case, scrape all the old FIPG off, do the output seals and bearings, and get it ready to go back in the truck (in an ideal world it is back in the truck tomorrow too, but I'm a realist and I don't think I'll get a full garage day in with family & life stuff.)

Hope this helps the next guy, I know I've soaked up so much from this board myself!

 

[lasoundguy]

OK, mild disaster ensued when I tried to do the rear extension housing. Will show details a few posts down.

Went along OK for the most part following the FSM, only a few "gotchas."

I didn't realize at first the "suitable" bolts aren't the bolts that held the oil pump cover in, they are one size larger. (14mm head)

Lock ring 1. A real pain with the pliers I had, I ended up grinding the head of the pliers down to fit more easily.

Oil slinger (?) came out easily. The pump plate behind it was a pain.

Finally got it out but took a lot of wiggling around and getting stuck, tapping it back down, then walking it back up by hand w/ a pick and my fingers through the sensor hole below.

 

[lasoundguy]

Lock ring 2--took me 45 minutes to get out. Ugh.

Lock ring 3, not so bad.

Emulating SST 09325-12010 with a 19mm impact socket, seemed to work fine.

Shaft free

 

[lasoundguy]

New seal and bearing ready to go in.

Lock ring #4 (screwdriver removal as per FSM)

Ready to press out the old bearing. Here's where things went south.

It seemed pretty hard, then "BAM" and it looks like I took out a piece of the housing. I'm not sure if this was seized up or if I used one size too big on the sleeve for pressing (looked right but maybe I caught the edge of the race instead of the bearing)? Aargh.

And then this happened.