• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Transfer-Case R&R+

JVZL1

PM 2024
PM 2023
PM 2022
PM 2021
PM 2020
PM 2019
PM 2018
PM 2017
PM 2016
PM 2015
PM 2014
PM 2013
PM 2012
Full Member
Joined
Jun 15, 2009
Messages
2,134
Location
Oregon
So I?ve gone through the Case Rub leak.  Sorry I do not have any pics.  I?m one armed during this process.  Hopefully this will help someone in the future just trying to get some things consolidated.
There are a lot of write ups for installing the case saver.  Here is another point.
There is another weak spot on the rear case. The retaining clip wears into the grove in the case that holds the clip and sometimes the clip breaks. A must spot to check over when you have the case apart if you are not replacing the rear case.
So if any one has input on this please feel free to add/modify.
     
REMOVAL;
Put T- Case in NEUTRAL; in owners manual and CAFCNA's Sperry Tech Center

When I talk about jacking the (transmission) up, do so ever so slightly. You can come in contact with the bottom of the truck and jack the truck off the safety stands!!!!!!!!!!                           On a lift;
Remove skid plate;
Drain T-case; plug is 18mm ( you will get some tranny fluid out of the tranny adapter when you separate, be prepared to catch some fluid).
I found removing the fill and drain plugs gives you just that much more clearance.
                       Floor Jack;
WITH SAFETY STANDS; REAR WEELS CHOCKED; E-BRAKE ON. Or supported by four Safety Stands with all four wheels off the floor.
          Front & Rear Drive Shafts;
http://chevyavalanchefanclub.com/cafcna/index.php/topic,43274.msg683948.html#msg683948
Mark yokes and drive shafts for lining up on reinstall. This will help keep drive shafts in tune and balanced.
Remove strap-bolts at differentials;
With the tires on ground no problem with drive shafts turning. If on a lift or off the ground on safety stands you may need to keep drive shafts from turning when taking off strap-bolts. I slip a long screwdriver/pry bar in the yoke.  Once bolts are freed they turn easy.  Slide rear dive shaft toward t-case, clear and remove.
Front drive shaft;
Remove the clamp on the t-case rubber boot (t-case side). Slide the drive shaft toward t-case clear and remove. Inspect the yokes on the drive shafts.
Keep end caps covered taping them is good. (Good time to replace u-joints).

I used a ratcheting strap around the frame to support the transmission. Keeping tranny and t-case in a neutral position and not wanting to fight another support or jack.
MARK ALL wires and plugs; (one of the You Tube links shows)
. There are three sensor plugs. (One on top easy to miss) A plug for the Encoder
Remove all wire plugs and breather tubes for t-case and tranny.

T-Case Vent Hose; The vent hose can be difficult to remove from plug on the t-case. Some cut the hose near the plug. I pulled the plug and replace ?O? ring
Move all wire and hoses out of harms way. I used wire/quick ties.

Removing The Tranny Cross Member;
Getting the exhaust out of your way is a simple drop for more clearance. This will give more room for removal and installation.
This is one of my trial and errors.
You may come across this in disbelief.  The inside bolt on the drivers side will not come out.  It hits the exhaust. You have to drop the exhaust or cut it off. I chose to cut it off. Well if you can not find a harden bolt long enough to fit, you may want to think this out and check price and availability of bolts from the dealer. List for the bolt was over $17 and it had to be ordered. Lucky it only took two days.  I used a block of wood that reached across the tranny to lift and support while I took out the tranny cross member.  Once cross member was out I let the tranny down until it was supported by the strap.  Also remove the tranny mount from the bottom. This will give you more room for removal and installing the t-case.

Optional; Remove Encoder; (FOLLOW SPERRY TECK FOR R&R)
 If you have a strong back and a good help you can man handle the t-case. So being old and one armed I purchased a tranny jack.  Remove t-case nuts and bracket on drivers side to separate from tranny adapter. (ARE YOU READY FOR SOME FLIUD) Support t-case on the jack and secure.  I used a ratchet strap.  The way the chain hooks on the platform is a joke.  The strap still lets you move the t-case (without it falling off the jack). If you did not remove the encoder, this is where you find it comes into play with the jack for tilting front to back and side to side.
For those who are going with out a jack to lift out t-case; Using the torsion cross member actually allows to balance the t-case with removal. You simply pull it back and down to drop it. Also, with the cross member in, when you go back to re-install, it serves the same purpose.

Separate the t-case from the tranny adapter. (HERE IT COMES) I then jacked the tranny up in small increments while moving t-case back, tilting the back of t-case up and over the torsion bar cross member. Take your time, this is tight and awkward.
Tilt up move back, tilt up move back repeat until clear and over cross bar.  Once separated and clear from the tranny adapter you can jack the tranny up some to help with clearing on the way down (the strap is still around the frame). I went up until I came in contact with the underneath of the truck.
Go slowly bringing jack down. Moving the t-case forward you can use the adjustments on the jack to help clear the tranny adapter. This is where strapping the t-case to the jack is safer than the chain. You can move t-case without it failing off the jack. Once clear slowly lower t-case all the way down. Remove jack and support under tranny from under the truck. Tranny is now supported by strap.
I jacked up the front end of the Avy just high enough to take out the t-case (MORE TRANNY FLIUD). With safety stands adjusted and the rear wheels CHOKED and E-Brake on roll out t-case.

INSTAL;
I did purchase the gasket from the dealer that goes between the t-case and tranny adapter with some RTV on the base of the studs. (No local auto parts listed this gasket).  Strapped t-case to jack, move under truck, position to lift up.  Go slow here.  Tilt jack so rear of t-case is starting to point up. Raise and tilt. When front of t-case was close to tranny I jacked up the tranny for more clearance. (Be aware of your clearances)   Back to raising and tilting jack to get the t-case over cross bar. Once rear of t-case is over cross bar start to level jack out while raising, jacking, and moving the t-case back. Now you are over cross bar and clear of tranny.  Keeping tranny braced up, move t-case forward. Using the adjustments on the jack, slowly move forward to align studs on t-case with holes in tranny adapter, also aligning the shaft. (This is also where strapping the t-case on the jack helped). They slid together quite easily. Position bracket back on drivers side t-case studs.
(Remember you are dealing with aluminum and magnesium VERY SOFT MATERIAL) snug up nuts on t-case.
Check Service Manuals For Sequence, Any Lube For Fasteners, And Torque Specs.  Tighten up nuts on t-case to spec.  Remove t-case jack and tranny support (Still have strap under tranny).
 Attach all wires and hoses. Do not forget the gray keeper for the encoder plug.  Attach tranny mount (first broken bolt).  If necessary, raise tranny to align bolts for the cross member. Install bolts, nuts and tighten (One new bolt and all new nuts facing the right way). Remove strap around frame and tranny.

Install Drive Shafts;
Align your marks.  Install and tighten strap U-bolts.

Installing new u-joints;
Being this is my first time with the injected plastic u-joints and replacing with aftermarket u-joints with clips, I was confused about how to install them in the pinion yokes. The yokes I have done before had a nipple or were recessed to hold the caps of the u-joints. There is not any on these trucks.  The yoke looks machined smooth.  So when I installed the rear drive shaft with the new u-joints I had slop between the caps on the diff. Searching, I found nothing to help. So I?m giving Canby Transmission a plug here.  They have helped me out a lot. Well, there is a slight grove machined in the inside of the pinion yoke. You have to really get in there to see them. Install the clips you get with the new u-joints caps. Turn the clips toward yoke side on to yoke with the clips in the groves. All better.  No slop.  
If you have the stainless steel clamps and clamping tool, clamp boot on front of t-case.  I used a wire tie.  Install Skid Plate.

FILL T-CASE WITH PROPPER FLIUD.
Truck needs to be level. So if you are like me, jack up just high enough for the extra to slide under supported with four jack stands and jacks.  
GM recommends TRAK II T-CASE FLIUD or appropriate ATF.
CHECK OWNERS MANUAL OR SERVICE MANUAL FOR AMOUNT/ PROPPER FILL LEVEL.
The Transmission will also need to be checked after start up and topped off.  

TOOL LIST;
DRIP PAN
Floor Jacks;
SAFETY STANDS;
WHEEL CHOCKS;  
Tranny Jack; this one did the trick;
http://www.harborfreight.com/800-lb-low-lift-transmission-jack-69685.html
Ratchet straps;        
? drive Impact; Air, battery, or electric; helpful if you have.
? and 3/8 drive;
Ratchet & extensions, Sockets deep & standard; MM 21; 19; 18; 17; 15; 14; 13;
Wrenches;
MM 21; 19; 18; 17; 15; 14; 13; 11
Helpful; flex head stubby 3/8 ratchet, 15mm stubby wrench or 15mm with flex end, 3/8 drive swivel or 15mm swivel socket. One of these will be helpful for the top nut on the T-Case.

I have attached some links for the R&R of the Transfer Case, some for the pump rub fix and rebuild. If you find or have any in put please add. I spent a lot of time with research and TRIAL AND ERROR.
http://chevyavalanchefanclub.com/cafcna/index.php/topic,120623.0.html
http://www.youtube.com/watch?v=Nj5ZS8wOmNk
http://www.merchant-automotive.com/transfer-case-pump-upgrade-kit.aspx
http://www.youtube.com/watch?v=yvZlmjLV4zE
http://chevyavalanchefanclub.com/cafcna/index.php/topic,141348.0.html
http://chevyavalanchefanclub.com/cafcna/index.php/topic,45517.0.html
http://chevyavalanchefanclub.com/cafcna/index.php/topic,141312.0.html http://chevyavalanchefanclub.com/cafcna/index.php/topic,90316.0.html
 http://chevyavalanchefanclub.com/cafcna/index.php/topic,41895.0.html
http://chevyavalanchefanclub.com/cafcna/index.php/topic,47353.0.html
Maybe not quite the way he doses it. (THE BIG BANG THERORY)
http://www.youtube.com/watch?v=R-LsFpQkn5M
http://www.youtube.com/watch?v=dfBMoAP7Ofs
If you want to surf.
http://www.youtube.com/results?search_query=GM+NP246+COMPLETE+REBUILD&sm=12

Encoder Motor Sensor Replacement
http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/417858-encoder-motor-sensor-replacement-w-pics.html





 
Back
Top