I'd like to install my Mag-Hytec cover this weekend. By the way, Happy Father's Day to you Dads!


The instructions talk about a "vent hose assembly modification." I have an '04 GMC 2500 (Dura/Ali). There's also a line about this not being a problem with the 14-11.5 rear end cover. So, can I completely ignore this portion of the instructions?


Also, I'd like to refill with Redline 75W90 All-Synthetic Gear oil.


http://www.redlineoil.com/products_gearlubricants.asp?subcatID=20&prodID=60


I've got 6 quarts on hand. Before I rip apart my pumpkin, will 6 quarts be enough?


Lastly, is the lube I've selected the right type for my differential? I've got the G80 (GM code) locking rear diff (I think this is standard on our trucks). I want to make sure I don't need to add some sort of friction modifier.


Thanks for the tips, guys.


~Terel

Mine took 8 quarts to bring it to the proper level. I was changing out the rear axle seals at the same time I installed my cover so it may have taken a bit more than usual. I'd have 8 quarts on hand before you start.Edited by: TC Dmax

Terel,


TC Dmax is right about the 8 quarts. You'll probably need a good gasket scraper or chisel for the OEM gasket, lacquer thinner works good for the residue. Put some Saran wrap or newspaper or the likes over the guts to keep debris out. If you jack the rear up (not the axle) by the receiver hitch, it makes things a WHOLE LOT easier. The vent clip (on edit: the e-brake clip) doesn't work with the cover (you could probably modify it). I think most guys let the vent tube rest on top of the pumpkin, IIRC there's a steel shield in the tube where it rests. You shouldn't need any friction modifier. Good Luckhttp://www.dieselplace.com/forum/smileys/Big Smile.gif.Edited by: GMCSLEHD

Guys,


Thanks for the feedback. If the rest of my rear-end is stock, will the hi-low marks on the dipstick give me the proper fluid level indication? (i.e. did they design it [correctly] so that I can rely on the level markers on the dipstick).


Thanks again.


Just changed my fuel filter for the first time. I used Eric's (Dmaxallitech) step-by-step guide, which made things VERY easy. I get a lot of satisfaction out of doing things myself. I just couldn't do it without this wonderful forum, though! Cheers.

terel
Yes those marks (high/low) are correct for our rear diffs.

(TC Dmax beat me to it)


My rearend is stock too. The dipstick will be accurate. Start with 7.5 quarts, drive it a little and recheck.


I agree this forum is great, a lot of good info!http://www.dieselplace.com/forum/smileys/Clap.gif


JoshEdited by: GMCSLEHD

Guys,


I fear I may have over-tightened my drain bolt. The instructions say 30 in-lbs, which is where I had my torque wrench set, but it's been awhile since it was calibrated. I torqued gently, and as the resistance began, the tension gave way. I've broken many a bolt before, so I feared the worst and backed it out. The O-ring broke, which explains why the tension gave way. As I examined the threads, the bottom 1/3 to 1/2 of the "threads" appear to be smoothed off (like when I overtighten things and strip them). But as I looked more closely, they almost appear to have been machined this way. Did I ruin imy plug, or do yours look like this too?


Also, when you guys fill, are you pumping through the sender hole on top of the cover or the hole on the face of the cover (near the Mag-Hytech logo)?


Thanks,


TerelEdited by: terel

To answer one of your earlier questions no I don't think you have to mess with the vent. I didn't mess with mine and it has been fine for 50K now. I used 8 qts of oil to fill mine. IIRC the threads on my fill plug were tapered too, probably makes it easier to thread into the case and not cross thread. Did you use an inch pound or ft pound torque wrench? That could be why you got it so tight. I wrapped my break cable with some rubber hose and tie wrapped it in place and it has been bouncing along ever since. Mike-

terel
Man that sucks, sorry to hear that happened. Is it the drain plug on the Mag Hytech cover that is fubared or the pumpkin? How do the internal threads look, are they starting to cross thread? You may have had a bit of leftover manufacturing debris in there and consequently caused it to burned off the first few threads on the plug or as you mentioned maybe defective threads from the get go. The threads on mine looked fine when I did the install, my only suggestion (just my opinion)would be to get a new drain plug if the internal threads look fine. I wouldn't want to have the plug back out on me while travelling, especially when we have no guages to monitor anything back there. Edited by: TC Dmax

Guys,


After more careful inspection, I determined that I did no damage to the threads (it was the Mag Hytech drain plug, not the OEM on the pumpkin). I just ruptured the O-ring. Quick trip to the auto parts store and I found a packet of O-rings that fit perfectly. I've got spares for the future, too,


I did use an inch-pound torque wrench, and I had it set right. I think it's time to get it re-calibrated. I've got six quarts in her now and will take her for a ride before re-checking.


As I filled her up from the dipstick hole, I left the bolt out of the hole on the face of the Mag Hyteck cover (not sure what this is for, the instructions call it a oil reference hole or something?). Anyyway, at about 4 quarts, it started to dribble out of this hole, so I bolted it up and added two more quarts. The dipstick now indicates that the level is right, but I need to drive a bit to make sure the oil is thoroughly distributed and so forth. I think I'll find that I need to add another quart or two like you guys.


Thanks for all the tips. Fun weekend wrenching on the rig. The Saran Wrap over the guts of the pumpkin was a terrific idea--kept all the old gasket and goop out of the gears while I prepped the gasket surface.


Take care!


Terel

I don't know about the '04's, but on my '02, the E-brake cable retainer did not fit with the Mag-Hytek cover. I modified it by flipping the retainer over and grinding off the part of the flange that was hitting the cover. If the link works, this is a picture of the finished product.


http://www.mcttrucks.com/gallery/Fireman/120266.jpg








Kevinhttp://www.dieselplace.com/forum/smileys/Big Smile.gif