Originally Posted by radomirthegreat
I can't wait for the first AWD L67! I'm going to go nuts! What would it take to install an additional LSD for the f-r in the AWD 4T65?
The front diff in the 4T65 Versatrak is the same diff as the std -65, the difference is the carrier is longer on the end and has a big helical ring gear welded to it (PTO). The guts are the same and I could build the EP-LSD for it. The rear is something entirely different. it does have the ability to drive both rear wheels under extreme front wheel slippage. SO for a short time, you would be true AWD! But the only time the rear actually drives is when front wheels are spinning, under all other driving conditions, the Versatrak is idle and the vehicle is in FWD mode. That'* why it'* a bogus AWD and a big POS.
Here are some pics of how it works:
Transfer case, notice the front diff planetaries, just like a conventional front diff.
the huge helical ring gear turns an idle gear...
...that turns the helical on the tranfer case "input" shaft...
...with a spiral-bevel gear on the other end...
that turns the spiral-bevel gear on the "output" shaft.
The rear driveshaft bolts to the output shaft.
The driveshaft turns the rear diff pinion gear...
Which turns the "idle" ring gear. The ring gear is part of the intricate clutch drive system, it is made up of two clutch packs engaged by pressurized oil in the rear diff. It gets [ressure from a gerotor-type pump, acitvated by the PCM when front wheel spin is detected.
So you see, it is a direct drive system, but only under certain curcumstances. It could be used very effectively as a drag racing set-up, but I don't know how much power it could transfer! I do know the AWD G8 was running in the 12'* and blowing out the rear diffs, three to be exact, before GM quit that idea. The thing about it is the transfer case has a ratio of, IIRC, 1.02:1. The front diff is the std. 3.29. The rear diff then would need to be a 3.33 inorder to run without breaking anything. I looked all around for a 3.33 R&P to decide what rearend you'd have to use (ditching the idea of a Versatrak rear diff which, as noted, has a 3.33 ratio.) The only thing I found close was a Ford 8" or 9" 3.25 ratio or the 12-bolt 3.36. You could stagger the tire diameters and get pretty close if not dead on.
I was building a AWD '95 GTP, 3400DOHC, twin turbo. I ditched it two years ago and kept all the good stuff. All this talk has got me wanting to try again on something else... maybe an AWD L67 GTP, but with a live axle in the rear, stock interior, stock appearing. I think someone else built one with a LS motor, not sure who... but it was RWD, not AWD!
I hate when my mind starts working like this, I can;t get anything doen just thinking and planning, planning and thinking. Anyone else have this problem?