marksmith

I put my truck into gear and it has a loud 'clunk'. Doesn't matter if its in forward or reverse. Still clunks loudly. I have narrowed it down to the rear end.

The truck (new to me) has 170K and change miles on her. It is fully loaded so I ASSUME it has the powr-lok in the rear end. I pulled the cover after I first purchased it to change the gear oil and didn't have the carrier turned so I could have a look/feel @ it. There are NO tags attached to the bolts.

SO... assuming that I have the powr-lok... Will the frictions wear and give excess slop in the spiders?

How do you rebuild them?


Thanks
Mark

TruckU

Did you use the friction modifier? There's a additive for diff's with lockers or limited slips that will help a little. My old '85 clanked from the day I bought it until I sold it, 80+K later and I never even changed the lube...

Most of the clunk comes from the spider gears moving around as the input changes direction, allowing the ring gear to move then slam to a stop. Make sure it has a second or two in neutral to relieve the load before going the other way seems to help a little.

brainfade

You can change just the clutches, they wear and like you said, increase the spider gear clearence. I put clutches in mine and it tightened up quite a bit. Mine came apart with just regular tools, didn't need a case spreader or anything special but I should have put bearings in it as I now have a little whine at 60+ mph. Most likely do that over Christmas break. I got clutches from precision gear as well as the additive. I put only one bottle in, the rear is a little tight, noticed some hop on sharp turns and the tires are wearing faster than before. When I put the bearings in I'll try two bottles and see if that loosens it up some.

dan1stgen

what does that power lok diff look like what kind of locker is it i got what looks like a ratchet locker in mine and it clunks and pops and engages when it feels like it. it looks like two machined steel cylindrical pieces with square teeth that are kinda spring loaded pressing together somehow they release and engage each other?????

JD730

marksmith,
I think everybody knows what happens you ASSUME, I would confirm you have a power-lok before ordering parts, of all the 1st gens I have at home, only 1 has a power-lok in it and 3 of them are LE's and fully loaded. Does it have any bad habits when you turning? Ours started getting real grabby in the corners when it was due for a rebuild with just under 200k miles on it.

I don't know what kind of tools and facilities you have, but I would recommend new bearings in both the pinion and carrier with those kind of miles, I'm glad I did, the one pinion bearing was eating itself to death, metal was flaking off the outer race.

The power lock is a clutch style diff with 2 cross pins and 4 spider gears. The cross pins are ramped so that when you put torque to one wheel it will ramp up and apply more pressure to the clutches further making sure both wheel pull. There are flat plates and belview washer(dished) plates, the flat plates have friction material on them, the other ones apply the pressure for the clutch.

When they are worn out the classic signs when looking at the carrier is clearance between the crosspin and the carrier.

Before you put the clutches in, soak them overnight in the additive, do it somewhere other than your house or basement, that stuff smells terrible.

Caver Dave

Ditto on checking it out thoroughly BEFORE you buy parts...

I've had the exact symptoms you listed (clunk going into any gear) and it was bad U-joint(s)...

dodgenstein

That sounds more like a Lock-rite aftermarket locker. A powerlok has a big squared off case with bolts that hold it together coming from the passenger side. The case is fully enclosed with small rectangular windows to allow lube to enter and triangular pins where they protrude through the case.

marksmith

I know about ASSUMPTIONS.


I think I'll tear into it next weekend (hopefully I can find a dry spot)


Anyone have a pic or diagram of a powr-lok?


As for replacing bearings and such.... I have access to the shop... but tearing into gears scares the crud outta me. Rear gears are too spendy for me to screw up. Do you have to re-shim and set up gears when you replace bearings? I would think so.....


Thanks guys. I'll let you know what I come up with.


Mark

KB440

Here is a link to Dana's website for the powr-lok

http://www2.dana.com/pdf/5315-3.PDF

wannadiesel

If the rear isn't howling leave the bearings alone, just pop out the carrier and replace the clutches (or the cross pin if it's an open diff). We have seen pics of a cross pin worn more than halfway through, that will give the same sort of symptom. This assumes, of course, that you've eliminated u-joints, slip yokes, and trans mounts as the source of the noise.

When you look it over to see what parts you need, check the condition of the spiders and side gears. I let mine go too far and the wear on the spiders and side gears was terrible, I had to replace them along with the clutches.

marksmith

Tranny mount is new. Not making noise. U joints are OK. New center bearing. Splines on the drive shaft still had the blue colored coating and was TIGHT fit putting back together.

If I disconnect the rear driveshaft and manually twist the pinion.... it will clunk.


All that is left is for me to tear into it and have a look-see.


I can pull the carrier no problem? Just keep up/down/left/right all the same?

wannadiesel

Yup, with 170k on it there is no need for the case spreader.

dan1stgen

just looked i got a lockrite locker fer shure. kewl!!! think i ate a spacer found some shardes of steel and a thin washer "spacer" in the diff. oops!!! that could be why it aint lockin and holdin on a wheel spin.

Caver Dave

If it's a Lock-Rite (or similar locker)... the shards could be the front edges of the "teeth"... notorious for rounding off & effectively NOT locking on straight line pulls (lot's of popping/banging unless it's worn to the point of just acting like an open diff). I know they don't seem to hold up well to DD asphalt use in offroad rigs, so combined with the weight/power of a CTD... could be a bunch of slop &/or shucked teeth...

I've only installed LRs in a D30 & D44... the only "thin washers" I recall involved with the locker itself are the cupped shims outboard of the side gears between the carriers interior. All the other shims are flat and likely shucked from under the carrier bearings...

KB440

The lunchbox style lockers don't hold up well in full size trucks. In light weight rigs like jeeps and such they seem to do pretty good.