jamesgmc

You do know who Gale Banks is don’t you? Banks Power is one of the most well know aftermarket producers of fully modified racing, off road and military vehicles. He isn’t “just” on youtube, he owms an international engine and drivetrain modifing company. Also you clearly didn’t watch the videos because the tests are being done in a controlled enviornment simulating highway driving at 70mph on a Dyno that is providing feedback. The diff, diff cover and axle are rigged up with all kinds of temperature reading equipment. They have even simulated airflow under the vehicle with a fan system. All of the controlled envionment specifications were obtained by doing on road testing to re create that in a lab on a dyno. So how is that not scientific? They are using the sane truck, same axle, same tires,, controlled consistent factors, on a dyno, and have multiple points of temperture measurement. Sounds pretty scientific, not to mention his company being several hundred thousand dollars invested into this. Cite your science the aftermarket companies are quoting. How does an aluminum cover provide more off road protection? This I’m curious about since I’ve been 4x4 trail crawling for some time and seen plenty of factory diffs clunk into rocks and be just fine. The diff cover is in the rear and unlikely to take a direct hit since it’s not forward facing. As far as tearing off that would literally have nothing to do with the diff cover and much more to do with the bolts holding the diff cover to the housing. In fact some 14 bolt diff covers actually only use 12 of the bolts so that would seem like it would weaken the ability to not be torn off. Not to mention if the diff housing took a hit hard enough to tear a diff cover off it would most likely either crack the diff housing or just tear the whole axle from the vehicle. Your statements in general dont sound that well thought out and kind of based on what you read from a aftermarket diff cover manufacturer. Also GM / AAM makes their own diff covers, they don’t buy them from another producer.

So interesting follow up to my OP. Bank Power is currently conducting tests on stock vs after market diff covers inregards to componet heat, oil heat and horse power to the wheels gains or loses. They happen to be doing their tests with the 14 bolt. Gale Banks hasn’t posted all the results yet, you can find parts 1 and 2 of 3 test videos on youtube. From what he is saying so far, aftermarket diff covers that add oil capacity and change the flow of the oil based on the more squared shape do three things: increase oil temps, increase componet temps and ultimately cause more drivetrain friction that reduces horse power to the wheels but they do look kinda cool. Check out his videos on the tests, very interesting, consistent and detailed.

So I am re-gearing my rings and pinions to 4.56’s. In the rear I have a 14 bolt 10.5 inch. I’ve noticed there is quiet the aftermarket for differential covers ranging from $40 to $280. I don't tow or haul heavy, I trail crawl and overland. Is there really a benefit to changing to an aftermarket cover? And if so, is there really a more significant benefit to running one if the fancy gill or slotted type covers that seem to be the $280 range? I’ve always looked at them more as one of two thing: first your OEM leaked so you replaced it, normal. Or: as some kind of a “subtle” way to let people know you’ve cracked open your diff(s) and probably have “something” in there. Attention seeking.

I did use gps to adjust for my speed. I havent actually messed with the speedo but if I’m highway driving I use a gps app. If my speedo says 60 im actually at 62 give or take. I upgraded to CST tie rods when I did my lift. And I did drop the diff to straighten out the CVs. I’ve accepted it’s going to be an open carrier but just wondering if the factoy CVs themselves are a weak point with an aftermarket “fix”. I don’t rock crawl or mud with it either. Pretty much just logging roads, fire roads and other un maintained dirt/sand type trails in California.

So currently I’m pegging about 1800 rpms at 70mph cruising. That seem high for 3.73s with 34.5s if you’re getting 2100 rpms at 70mph with 4.56s and 34s. 2100 rpms isn’t bad at all for 70 with 4.56s, I would have thought you would have been closer to 2600-2700 rpms. I generally cruise at 60 so I’d be under 2100 aswell. Any insight on strengthening the 9.25 IFS? I’ve seen aftermarket CV shafts but not really sure those need upgrading.

Thanks again for the info Sierra!

Thanks SierraHD17. I want to make sure this project is getting done correctly. When you said what I've been told is right, were your referring to the parts clerk at the Chevy dealer when he told me I need to replace my entire drivetrain? That seems to counter what I've read and watched from hundreds of people talking about changing gears in a diff. My understanding of my project is I need to change my rear ring and pinion to a 4:10 or maybe consider 4:56 with the appropriate Truetrac carrier. No one seems to make a reputable locker or LSD for the front GM 9.25 so I'm planning to just install matching gears to the rear. Of course each install will be done with a master install kit with the appropriate bearings, seals, gaskets and silicon. As for my actual axles, drive shafts, transfer case, transmission, and yokes I'm not planning on touching those.

Thanks for the info

Lol just to add comedy to this post, I called my local GM dealership and asked for a quote on the 4.10s just to compare. The parts guy told me I can’t just change the ring and pinon in the diffs, I would need to bring the truck in and have them do a whole drivetrain swap (axles, transmission, transfer case, drive shafts, yokes) off another 2500 that has 4.10s... I just said thanks with a chuckle and hung up.

Hi community, seems like there is alot of information out there about the various GM 14 bolt axles, how to try and ID them from the outside and what model year/trim trucks have what. I have a 2014 GMC Sierra 2500 crew cab, standard bed, Z71 with a 6.0 gas. I know most of these come with 4.10s but the RPO code (GT4) exsists on my tuck indicating it has 3.73s. Funny enough the RPO references online seem a bit out of order as my truck has the L96 code which according to some indicates I have a 2.0L I4 lol. So I’m going to re-gear and ditch the G80 for a truetrac. To my knowledge there are no RPO codes that tell you weither you have a 10.5 or 11.5aam axle? Anyone have any insight as to which I have or how to find out without taking the diff cover off and measuring? I know you can take it to a dealer and they will tell you but they also told me the truck had 4.10s when I brought it to them after I bought it used from a CarMax. Also pretty sure upfront I have a GM 9.25 unless anyone knows better?

Thanks!

Hi community, I have a 2014 Sierra 2500 4x4 with the 6.0 Gas. I've read and watched some videos about known issues with older GM transfer cases have pump knock that leads to a hole in the case. Is this an issue with 2014 2500s? Thanks for insights. Edit: I should note, have not had an issue with my transfer case at this point. Just want to know because I'm going to be taking apart the drivetran to upgrade the diffs and might as well bullet proof the transfer case if I'm doing the diff work. I've done some more digging and found that GM switched to a new transfer case 07/08, MP1226XHD. My rig has a corresponding RPO code of NQF. Does this transfer case have the issue the older NP cases have? Not alot out there about them.

Hi community! So 4x4 build question for folks. I have a ‘14 GMC 2500 C/C SB Z71 with the six 0 and 4:10s. It currently has a 3 inch lift in the front and 1 inch lift in the rear, just shy of level. I love the GMC stock rims and really don’t want to replace them. I have the 18x8 rims and currently have 270/75/18 Ko2s on them. I actually do go off into jeep country, do overlanding and earthroaming with the truck and have a 12.5k Warn on it for getting unstuck, KO2s and 4 low havent failed me yet. Time for the question: Does anyone know if I can safely fit 35 x 12.5 KO2s on the 18x8 rims and safely be air’d down to 35 psi if needed? I don’t really 5th wheel or trailer with it, occassionally “Home improvement” loads from Home depot in the bed so im not really concerned with running over 65-70 psi. All the tire places recommend atleast 18 x 8.5 rims for 35 x 12.5 tires but I’m wondering if that half inch really makes a difference since I know people run even wilder size gaps but usually on lighter vehicles like jeeps and 1/2 tons. Also any insight on the tires not rubbing with the factory backspacing based on my lift? I’d really like to get the extra 1ish ground clearance at the pumpkin from moving up to 35s (34.5). Thanks, James