Long story short, after some abuse the 3/4 shift fork gets a little bent, and common issues are popping out on decel, and grinding going into 3rd gear. I wrote this for srtforums.com and figured I would share te knowledge. I can also rebuild the trans. 03's are the easiest. 04's and 05's have needle bearings, and LSD's.
A lot have asked for a How-to for this subject. I was doing mine today so I decided to make one. Enjoy. :thumbsup:
Remove battery, tray, air intake and anything obstructing access to the top plate on the transmission.
[You must be registered and logged in to see this image.]Pull up on the shift cables, they pop right off. Move to the side.
I recommend removing the trans mount. Its one 1/2in mount bolt and it gives you room to wrench. Be sure to support it with a jack and a wood block, this will also aid you in lining up the trans mount to slide the long bolt back in.
Remove the seven 13mm bolts from the top plate. I use a gear wrench for this.
[You must be registered and logged in to see this image.] Note: The bolt under the counter weight will NOT come out of the plate. The idea here is to loosen it last and bring the plate up off the trans while rotating the bolt counterclockwise.
[You must be registered and logged in to see this image.]Cover the exposed transmission with a towel or something to prevent objects from falling into it.
Place your trans plate in a vice, or secure it somewhere you can bang on it and it won't move.
[You must be registered and logged in to see this image.]Using a punch and hammer, or mallet, remove the two pins in the shaft. They hold the shift selector on and the stock _____ (IDK what the OEM item the 3rd gear extender replaces is called)
Note the positions of the items before removing them.
[You must be registered and logged in to see this image.]Stock part on the left of the 3rd gear extender for comparison.
[You must be registered and logged in to see this image.]Clean the items with something, I used a "lint free" shop towel.
Re assemble the shift selector and 3rd gear extender onto the shaft and make sure the notches are properly aligned.
[You must be registered and logged in to see this image.]Install locking pins.
[You must be registered and logged in to see this image.]Clean the mating surfaces of the plate and the transmission. I use paint thinner and a wire brush. If you do this you MUST have a shop vac to remove any dust or debris you agitate on, in and around the open transmission.
[You must be registered and logged in to see this image.]Run a bead of Transmission Anaerobic sealant. Failure to use the appropriate sealant may result in seal failure and corrosion.
I use this:
[You must be registered and logged in to see this image.]Install plate onto top of transmission. Note: I place the shift selector in the middle position to align the internals and make sure the forks are aligned to allow the selector to slide into them.
[You must be registered and logged in to see this image.]Begin tightening the bolt under the weight first. As you tighten each bolt periodically move the counterweight to ensure it moves freely and without restriction.
I can't fit a torque wrench in the bay there, so I tightened the bolts until I was confident they were tight enough. Some people use Loctite or Threadlock, that is acceptable, as long as the bolts are in fact tight.
Attempt to shift the car, engine off, into each gear. I have never had any problem not being able to do this after install.
I lost the end to my sealant, so that's the reason for my putty knife and fat ass bead. I cleaned it up before I put the plate in, so nothing dripped into the trans.
Subject: How to install a third gear extender in a T850. (SRT-4 and Sprinter) 
Mon Oct 03, 2011 10:02 pm
