Well I hope I'm right by saying this, fairly certain I am...
The problem is with the 8.25" open axle, apparently the spider gears and
side gears are slightly softer than the axle (which they should be.. cheaper
to replace them than an axle shaft). The problem I had was with these
gears. The slightest amount of wheel hop and they'd be missing chunks out
of the side/spider gears. My stock spider/side gears were tested to a
Rockwell 58-61. These were replaced after I found a few chips in them.
Unfortunately, the replacement gears were piss poor. They came apart in 8
months, basically just self destructed.. These tested to a Rockwell 23!!!!
*note* those were NOT DC issue gears... but cost me a pile of money!
After those cheap gears destroyed my axle, I went to a junkyard and picked
up an 8.25" SG axle. The SG axles incorporate a larger set of spider/side
gears.... It's seen it's share of abuse, and the couple of times I've craked
the cover there have been no visible signs of wear or chipped teeth. It has
however, developed a howl.
I've seen this howl develop on several Fbodies that run low 13s, 12s, and
high 10s. After talking with a GM axle guru, that axle's problem is the
huge amount of torque. From the pinion gear's perspective, the torque tries
to shove the gear rearward and out the back of the differential. Thus after
several/many hard runs, the crush sleeve (holds pinion depth) gives a little
bit so therefore the pinion/ring gear lash will be slightly off, producing a
howl. The fix? less torque (ok, that's not a fix..), stiffen the axle, or
get a bigger axle. There are diff covers out there with girdle supports,
which place a preload on the bearing caps which will stiffen up the unit.
I think *knock on wood* that the 8.25" SG unit is strong enough with the
larger spider/side gears to last behind my auto tranny, with a manual tranny
I'd make an axle swap my very next mod.
I'm betting your friend's bird has the A4 tranny? The guys I know down here
that run 10s with beefed up axles have already replaced a couple of them.
When you're making that kind of power, it's only a matter of time till
something lets go.
_______________________
Jon Smith--Raleigh, NC
jon@fast4x4.net
www.fast4x4.net
> Jon, I know you have had your problems with that 8.25" rear, but from what
I
> understand the F body GM cars that produce over 300 hp use a 7.25" ring
gear
> and I know personally a friend who runs 10's in his 98 bird (500+hp) with
a
> 7.25" rear with no breakage. I'm just wondering what the weak spot is in
> the 8.25" DC rear??? Is the pinion diameter small, or just the materials
> poor?? I wonder how those GM guys are making that 7.25" last??? What
> do you think?
>
> __________________________________
> Matt--VA--Y2K-HEMI `00 Sport Plus RC
> ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
>
>
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>
> -----Original Message Follows-----
>
>
> From: Jon Smith [mailto:jon@fast4x4.net]
> Sent: Thursday, September 14, 2000 8:11 AM
> To: dakota-truck@buffnet.net
> Subject: DML: Re: Gen III Durango axle to a Gen II Dakota
>
>
> already considered that route... after talking with several ppl I decided
> it'd be too difficult a swap, there is rumor that a 8 3/4" from a B body
> bolts in w/o any shortening, just relocate the spring mounts...
>
> keep us informed, I'm sick of the 8.25"
> _______________________
> Jon Smith--Raleigh, NC
> jon@fast4x4.net
> www.fast4x4.net
>
>
> > Hi all,
> >
> > Does anyone know if it's possible to bolt in a 9 1/4 from a durango into
a
> > Gen II Dakota? I seem to remember something about the new trucks being
> > wider but was it just the body or the whole truck?
> >
> > Thanks in advance,
> > Tim
> >
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>
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