snowriderz
New member
I had mine rebuilt at a shop in in Portland . So far so good 20k later . https://g.page/river-city-transmissions-or?share
GM fullsize AWD Van Info thread
- Thread starter boardrider247
- Start date
snowriderz
New member
Thats what i have ! I like it .
truckee travelers
New member
Would like to re-gear my 2014. Has anyone done this and what cost are we looking at. My 3.42 factory gearing with 285/70-17 is not working in the mountains. Eventually going to downsize the tires to 265/70-17 and thinking of re-gearing to 4.11. Any thoughts on this setup for mountain driving, or should I go with lower gearing. I'm in the Reno area and called one shop and they didn't seem to want anything to do with it and said the frontend/transfer case would have to be shipped out.
I drive mostly in the Sierras and have 3.73 gears and 33" tires. I really want lower gears, I will eventually go to 4.56. I have got a few estimates between $2600-$3000. Most good 4x4 shops do gear changes and don't need to be sent out. No need to touch the transfer case.
boardrider247
Weekend warrior anarchist
Steve, so these shops are telling you that gears are available for the front diff? That was my only question was whether the parts were even available for a regear?
I've honestly never looked into it though.
I just completed re-gearing from 3.42 to 4.10 s yesterday and went for a quick test drive, just 13 miles all below 45 mph, very gentle. I'm on 265/75r16 rubber. I also put in a reman BW4473 because my transfer case was generally worn out, the viscous coupler was locked up, it had the original rear case half with the cast bushing that was worn out, so the parts to refresh it myself was going to cost close to what the reman cost me.
Note that I had been awake for about 24hours straight on only 3 hours of sleep the night before, so brain function was not high during the initial drive. A few observations that indicate changing gear ratios on our vans may not be super straightforward...
1) It immediately popped an ABS/brake system code "Wheel speed sensor frequency out of range"
2) The speedometer was 7.5-10% over actual (gps) speed.
While I have a bit of experience with changing tire sizes, gearing, and speedometers in general, and some experience inferring how vehicle systems work based on observation, this is my first go-round with a GM vehicle. Below are some of the factors I'm considering...if anyone as more info or ideas to contribute I'd take them.
1) I think that vehicle speed is calculated from the transfer case output shaft sensor (very slim but possible chance that the wrong reluctor wheel was installed as their are some common parts shared with the BW448X series cases) I'll test this by unplugging the sensor and see if speedo works and/or changes. The rough calculation the bcm should be doing for speed (minus details of conversion) is output shaft rpm times diff ratio times circumference of tire = speed. Bigger tires along with a lower gear ratio should help balance this out. This might be an excuse to upgrade my tire/wheel combo to 285/70r17 in order to make the speedo more accurate. Will do some of the math to see if the changes I made make sense in terms of speedometer output.
2) ABS system monitoring compares t-case output shaft speed to wheel sensor speed to confirm function (this is a guess based on what I saw) tire size will have no effect on this test, but may effect performance of the ABS system.
3) It is possible that the BCM is programmed for specifically for the OEM ratio, or the program is the same for either 3.42 or 3.73 ratio and the resulting range of results (speedo, ABS, etc.) is acceptable. If the bcm is specifically programmed for 3.42 gearing, going to 4.11 is a big jump.
I'm just getting caught up on sleep now, so haven't had much time to think about it or research. When I have the time to drive the van again and confirm what I saw, I will report back results and/or a fix as I learn more. What I need is a GM tech that knows these systems well, but it seems like everyone at there on the webs is either focused on LS swaps or modding trucks.
The gears are available. I have even priced out the parts and considered doing it myself.
High performance Yukon Ring & Pinion gear set for GM IFS 7.2" (S10 & S15) in a 4.56 ratio | RANDYS Worldwide
I know you asked TeleSteve, but since I just did it I thought I could answer. The rear diff is shared with a lot of vehicles, so tons of options are available. There are parts available for the front diff, but options are limited. OEM style 2 cut R&P are not available for the front, and because of the size difference between the 8.6" rear and the 7.25" front the ratios don't match exactly. Usually this slight difference in ratios is not a problem in 4wd, but for the AWD transfer case it might cause the viscous coupler to fail more quickly. I plan on doing a tcase swap when I replace the transmission, so I thought I would do the experiment and see what happens. There might also be a way to manipulate the tire pressure to help make up the difference, but I haven't thought that one out yet.
truckee travelers
New member
Thanks for the info. Talked to a shop in Reno and acted like it would be no problem to go with 4.11 for ballpark of $3500. Little concerned about the ABS and any other problems, ie. Vibration. will downsize the tires first. like the look of the 285's with 2" lift and suburban springs in rear but damn needs more power and options are limited.
truckee travelers
New member
Let me know how it goes. Seems like all I see is 4.11. The 5.3 does do better at higher RPM's. I just want something that can do 75mph without the darn constant down shifting. I'm cussing GM all the time for not putting the 6spd transmission in this thing.
I haven't had time to drive again yet, but did some research and solution is easy. You can recalibrate the tire size and gearing using any number of programmers. Hopefully the shop you talked to has the capability (I would ask them).
If not the Hypertech 732501 looks like it would do the trick for around $189.
I'm actually looking into HP tuners programmer because I am wanting to try to do a 6l80 swap when my trans dies, and will need more capability than the Hypertech. A gm dealer can also recalibrate, but finding a tech who both knows how and is willing to do it sounds difficult at best.
EDIT: Changed part number for Tuner
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I am a little better off with the 3.73s, so most highway driving is fine, but around home in the steep winding roads I would like lower gears, especially when towing my snowmobiles. The 6spd would be awesome, but probably more money than it's worth for my old van.
With these storms lined up, I might actually get to use them too.
I've got just over 100 miles on the new 4.11 gears now. I just took a quick drive after using HPTuner to re-calibrate the ratios and tire size. ABS and speedometer are working correctly again.
HPTuner ended up costing $450 after licensing, has a steeper learning curve, and runs the risk of bricking your ECM. I would only recommend it over the hypertech if you are planning other mods in the future that would require reprogramming.
I'm still in the break-in period, but once I get 500 miles and a fluid change done I'll be able to get in the mountains with my sled trailer and report back. I can't wait until I can get a full WOT from a stop to feel the difference.
My initial impression is that 4.11 are just about right for 31-32" tires even in the mountains, and that 4.56 might be too low if you are logging significant highway miles.
HPTuner ended up costing $450 after licensing, has a steeper learning curve, and runs the risk of bricking your ECM. I would only recommend it over the hypertech if you are planning other mods in the future that would require reprogramming.
I'm still in the break-in period, but once I get 500 miles and a fluid change done I'll be able to get in the mountains with my sled trailer and report back. I can't wait until I can get a full WOT from a stop to feel the difference.
My initial impression is that 4.11 are just about right for 31-32" tires even in the mountains, and that 4.56 might be too low if you are logging significant highway miles.
Question for you express folk. A couple years back I "graduated" from an AWD Astro to an AWD Express (to which I added a Fiberene high top).
One thing I really miss about the Astro is the "hatch" that gives some sun and weather protection at the rear doors.
So, naturally I think about a rear awning on the express. However, with the high top, the mounting options get a bit wonky (the roof AND the rear is curved, naturally) and I'm at a creative loss as to how I might mount an awning that doesn't just allow water from the roof to drain into the open back doors. I know there isn't an easy solution, so I thought I might ask the crew and see if the collective mind has been more creative than mine. You usually are!
Thanks in advance
The best I can come up with is to add some exterior drain channels that might move the bulk of the water to the sides. but I still see a lot of "holes" in that idea. Clearly the problem is exacerbated by the addition of the high top, There isn't likely as much water draining into the open doors on a stock van.
One thing I really miss about the Astro is the "hatch" that gives some sun and weather protection at the rear doors.
So, naturally I think about a rear awning on the express. However, with the high top, the mounting options get a bit wonky (the roof AND the rear is curved, naturally) and I'm at a creative loss as to how I might mount an awning that doesn't just allow water from the roof to drain into the open back doors. I know there isn't an easy solution, so I thought I might ask the crew and see if the collective mind has been more creative than mine. You usually are!
Thanks in advanceThe best I can come up with is to add some exterior drain channels that might move the bulk of the water to the sides. but I still see a lot of "holes" in that idea. Clearly the problem is exacerbated by the addition of the high top, There isn't likely as much water draining into the open doors on a stock van.
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Question for you express folk. A couple years back I "graduated" from an AWD Astro to an AWD Express (to which I added a Fiberene high top).
One thing I really miss about the Astro is the "hatch" that gives some sun and weather protection at the rear doors.
So, naturally I think about a rear awning on the express. However, with the high top, the mounting options get a bit wonky (the roof AND the rear is curved, naturally) and I'm at a creative loss as to how I might mount an awning that doesn't just allow water from the roof to drain into the open back doors. I know there isn't an easy solution, so I thought I might ask the crew and see if the collective mind has been more creative than mine. You usually are!
The best I can come up with is to add some exterior drain channels that might move the bulk of the water to the sides. but I still see a lot of "holes" in that idea. Clearly the problem is exacerbated by the addition of the high top, There isn't likely as much water draining into the open doors on a stock van.
I couldn't come up with a good way to mount an awning that diverted drips either, so I ended up using a Slumberjack Roadhouse tarp instead. It works for me because we tend to live out of the side door and use the tarp to create a covered area between our (detached) trailer and the side of the van. Our back doors are mostly storage so don't get accessed much once in basecamping mode. You could probably rig the tart to easily set up off the back though.