| Dana 44 Trac Lock rebuild Tech Thread |
Subject: Dana 44 Trac Lock rebuild Tech Thread by rklessdriver on 2012/8/28 1:53:31 How to inspect and rebuild your Dana 44 Trac Lok positraction unit. Obviously first thing is to get the D44 center section out from under the car and on to a workbench with a big vise so you can work on it. I’m not going to cover removal of the center section from the car as it’s already been done on this forum. Now how do you know if your Trac Lok Positraction is even in need of re-build??? That’s a good question…. The Spicer Manual 5313-3 states that the Trac Lok should hold a minimum of **25ft lbs**. Now you can check that a number of ways but I do it with a 36mm socket and a beam type TQ wrench on the outer stub axle nut. Jack one wheel off the ground put the car in neutral and start pulling on the TQ wrench until the Posi clutches break away…. That’s your initial reading or “break away”…. As you continue to pull the wrench you’ll notice it requires about 5ftlbs less to maintain clutch slippage…. This reading is your “constant”. BTW you’ll want to check both sides so you have an accurate read of both clutch packs. **I want to note that for a high performance car like the Corvette - IMO 25ft lbs is woefully inadequate. For comparison a new Spicer Trac Lok unit will take 75-85ft lbs to break loose and a hand built, properly built unit can take over 150ft lbs. For a lot of racing use with most cars I’d suggest a rebuild when it gets under 65-70ft lbs. When these things blow up they do some MAJOR damage.** Once it’s out of the car the best way to work on it IMO is to turn it upside down and clamp the C Beam attachment point in the vise. The first thing your going to inspect is the inner stub axle end/side play. Use a feeler gauge to check the stub axel against the spider gear cross pin shaft. On this one the drivers side measured .007 and the passenger side measured .011…. indicating something is bad wrong, which I already knew since it required barley 15ft lbs breakaway. Write the measurement down.  Next remove the axle-retaining clips…. Your going to need a REALLY good set of snap ring pliers, a helper and some patience. Use the pliers to open the axle-retaining clip up while your helper pulls the stub axel out. There is no need to mark the axles as they are different lengths and can only go back one way.  Optional step - Next (if your going to) check the ring gear backlash. You’ll need a strip of meatal bolted to the housing since it’s alum. Set up the dial indicator on the drive side of the gear (the convex side). Hold the pinion still with your hand and rock the ring gear from one end of it’s free movement to the other. The measured distance is your back lash. On this particular gear set for the D44 the Spec is .005-.008 - These gears measured right on .005, which is better for drag racing.  You’re going to need to remove the bearing caps. Be sure to mark them so you can put them back in correct position… I have always used “D” and “P” (Drivers & Passenger).  Once the caps are removed you’re going to need to remove the ring gear carrier/Trac Lok unit. Sometimes they are in there tight so a pry bar is needed…. Just use a ring gear bolt to pry on  And have your helper hold his hand in a protective manner to keep it from flying out and on the ground. The bearing races are going to want to fall off so store the bearing races with its respective sides bearing cap so they don’t get mixed up.  |
