Posted by TomT on October 31, 01 at 14:11:04:
In Reply to: Re: clarifications posted by Traveler on October 31, 01 at 13:44:26:
Traveler,
Once again, you have made some good points. The only thing that I disagree with is the Gov-lock and friction modifier. There was a clear notice in the owner's manual to service the stock limited slip diff at 5,000 miles that I overlooked. When I inquired about it, I was told (possibly incorrectly) that the friction modifier is not added at the factory for break-in and that I should have serviced the diff at 5,000 miles and added the modifier. By not doing so, the weighted/levered mechanical system they have in the Gov-lock will lock up with heat from an extended hiway drive, then when you attempt to make a turn (i.e. the offramp of a freeway), it acts like a spool in rear only the components can take the stress and things start to break. I'm not saying that this is still the case. It was with my '93. This same thing happened to an '88 FS Blazer in our company truck some years back.
Yes, I made a mistake installing the clutch-type limited slip; I thought it would be a better compromise - simpler design, better performance, not so many moving parts, without the noise of an honest to goodness locker. With the limited articulation of GM IFS, I should have installed a Detroit or similar locker if I wanted halfway decent off-road traction.
I have often made poor decisions, because I have received recommendations about a component being "way too much for how you use the truck." Many times I am afraid to use the truck as I would like, because I feel that it is underequipped (i.e. clutch-type limited slip vs locker). If I had the locker installed, I'd be able to ease the truck up hills rather than having to beat on it more than necessary to make a hill. For instance, I was told that the Flowmaster cat back system that I now have would be "way too loud", but I love it. Live and learn, as they say.
Anyway, food for thought for those contemplating upgrades. IMO, it's better (not always, of course) to overbuild something rather than be overly conservative.
Thanks for your input.
Tom
: : 2) This sounds a lot like someone who didn't service the crappy 1/2 ton Gov-lock (like me). I never added the friction modifier to my 1/2 ton diff.
: You are not supposed to
: :After heating up on the hiway, the thing locked and released after turning around the corner. Also, the inside tire locked up as well to add a bit more drama to the deal.
: Once it has overheated, the tolerances are gone from metal expansion and it can't work as designed. I don't like spiders anyway.
: :After the spider gears exploded, I replaced the Gov-lock with an Eaton unit. If I had it to do all over again, I would have put some sort of locker in the pumpkin as the lousy articulation spins the light side with the limited slip.
: The Gov-Lock IS an Eaton. You put in a limited slip posi from Eaton, and found they don't work well in trucks; ie, that's why you had the Gov-Lock to start with. A limited slip only works well when both tires have traction, like a hot rod on pavement. When one tire is on mud or ice, you can't develop any torque to cause the force that compresses the clutch packs. The locker recognizes this and uses a centrifugal actuator that does not depend on torque being developed.
: : I can't say much about the tranny. The 4L60E is kind of weak. I've got 130K miles on mine, but the 1st to 2nd gear shift when it is hot under full throttle is very sloppy, so I have to baby it.
: It is as strong as GM designed it, but they use it where a heavier trans should have gone. Sloppy shifts will wear it out faster, so a service call or shift kit is needed.
: : BTW, when I bought my 3/4T '01 Burb 4X4, the differential service was one of the first questions out o' my mouth.
: : It seems as though GM has somehow addressed it now.
: Yes, after perturbing many customers because they will not admit they were wrong. Boneheads, but nothing changes as long as the fat cats get their bonuses.
:
: : Good luck and I welcome opposing opinions,
: : Tom