What did you do to your GMT today?

[dvanbramer88]

Nice job Robert!

[navigator]

ok, I got my rear diff in finally.
with 3.42 and 32's my speedo would read 60 and I was running about 63.
with 4.10 and 32's my speedo reads 60 and I am running about 58.
I expect if I move to 33's my speedo will be pretty close.

If you check the math, I'm pretty sure you just put in 3.73 gears, not 4.10s.

now you have me worried
I remember though on both the front and the rear turning the driveshaft a little over 4 times to get one full wheel revolution so it should be right.
Can you share the formula you used?

I tried to figure it out but can't.

[Trail X]

Its just a ratio thing. At a set RPM (60 on your speedo), you used to be actually going 63 now you are actually going 58. So the ratio of speeds should be equal to the ratio of gear ratios. 63/58=3.73/3.42 Take away any of those numbers and solve for the missing number. For instance, 63/58*3.42=.... 3.714. You can replace numbers around and find that if you had 4.10s, you should actually be going about 52 or 53 mph when your speedo shows 60.

[Cable810]

if you had 4.10s, you should actually be going about 52 or 53 mph when your speedo shows 60.

Sounds right for me. 65mph = 57mph

[navigator]

oh crud...
Let me check the rotation again, and the rotation of my front gears.
I remember setting the scangauge to read +6% with the 3.42s and that was about 1mph high
For these gears -3% is right on the money.

Honestly I was disappointed in the performance improvement, if they sent the wrong rear end, this would explain it.

[Moots1288]

Installed Tuned PCM, waiting on Dashhawk scan tool to do Case Relearn.

[Eredin]

Replaced driver caliper bracket on Sunday afternoon. Gathered rocks behind the dust shield and noticed under breaking from that side, so trimmed that and noticed the caliper pin wasn't moving on the top side. Tried to break it loose and it snapped in half inside the bracket. Easy fix, but unexpected. Still haven't figured out how my pads weren't wearing uneven, but good to go. Just have to trim out the passenger side and figure out where the incessant squeaking is coming from in the rear.

[ErikSS]

A ceased guide pin (caliper bolt) would cause uneven wear. Did the other bolt slide in the caliper by hand?
You may have fixed both issues at the same time!

[Eredin]

Yea, the other pin was perfectly fine, the upper had rusted half way through and snapped when we applied force to attempt to free it up. Pads look perfectly fine, changed them maybe 30k ago and didn't notice the problem then, but that was probably 3 years ago.

This thing has been unusual. Most bolts come out perfectly fine, but there are a select few here and there that look like they've sat in a salt bath for years and break without much effort. Snapped one of the frame bolts for the lower control arms a few weeks ago. That was fun. -_-

[navigator]

If you check the math, I'm pretty sure you just put in 3.73 gears, not 4.10s.

You were right James, I just did another rotation count and one turn of the wheel rotates the DS about 3 3/4 turns.

The front diff I double checked and it is pretty much exactly 4 turns

I'm not sure how in the world I missed it previously...
More fun to sort through.

[Trail X]

Better to find out now than when you need 4wd.

[Wahugg]

3.73... 4.10... they both round off the 4.0; Close enough right? It's not like our drivelines are weak or anything.







But in all seriousness glad to hear you found it out before your gears decided to say 'bye bye'.

It looks like you could find the cheapest 4.10 axle around and swap the ring gear/pinion with your current diff or you could look for a G80 (or open for a lunchbox locker) 4.10 and just swap the whole axle out, selling the 3.73 G86.

-Wahugg

[navigator]

yeah, really glad JD did his quick math quiz.
I'm going to call the JY I got the rear from and see what they say.
It has been so long, I expect I am out of luck.

[Moots1288]

Why don't you just take the cover off... The ratio is stamped on the ring

Sent from my SPH-L720 using Tapatalk

[navigator]

I did, I rotated it several times, there was a long number on the ring but no ratio that I could see.

[dvanbramer88]

I shampooed my carpet yesterday. Got all the coffee and grease stains out. It looks really nice. Detailed the interior for our vacation. Washed the outside. Organized all the crap in my tool box. And today, I installed my new exhaust.

Cat delete, Flowmaster Scavenger Y pipe, 2.5" tubing, into a Thrush 2 chamber muffler, and using the factory tail pipe. Sounds pretty darn good. No leaks so far.

Idles quiet with a decently deep gurgle, Has a very deep rumble around 2K rpm, and if you want to jump on it and make it roar you can. Below 2K when you're cruising, it has a very low and mellow drone you can barely hear in the cab.



The old leaky pipes and shot out muffler.




The new stuff mocked up in the shed. It started pouring yesterday before I had time to work on it.

[navigator]

so the JY is no help on my rear diff.
Even though they sent me the wrong diff they said they would take the diff back after a 20% restocking fee and I had to ship it on my own.

So I think I will search locally and see if a rear 4.10 is avail here, if not I might try to find a 3.73 front to match the rear I have. While it isn't ideal it should still meet my needs. I think the 3.73 with 33s would be pretty close to stock ratio wise.

[TBYODA]

so the JY is no help on my rear diff.
Even though they sent me the wrong diff they said they would take the diff back after a 20% restocking fee and I had to ship it on my own.

So I think I will search locally and see if a rear 4.10 is avail here, if not I might try to find a 3.73 front to match the rear I have. While it isn't ideal it should still meet my needs. I think the 3.73 with 33s would be pretty close to stock ratio wise.

Personally I'd suggest this http://www.summitracing.com/parts/sum-741004/overview/ + a install kit I think be cheaper than a new rear or a wash and you be better off.

[navigator]

yeah, Robert, I have thought about that option as well. I would need to call in a favor to a friend to get him to help me set them up. I guess the good news is I would then have that experience.

[DirtyBacon04]

So I think I will search locally and see if a rear 4.10 is avail here, if not I might try to find a 3.73 front to match the rear I have. While it isn't ideal it should still meet my needs. I think the 3.73 with 33s would be pretty close to stock ratio wise.

...I've got a 3.73 front diff for sale