Ox Locker in GMT900 with 3.42 gears?

[strutaeng]

@strutaeng

That's an excellent video. Thoroughly informative yet not too long and drawn out. I've seen it before years ago but forgot how good it was. Looking into a TrueTrac at this point and possibly re-gearing to 3.73's.

I've heard/read many say that's a pointless re-gear - if you're gonna do it, might as well go up to at least a 4.10 - but I think for my application it'll be well worth it.

It's a 2wd DD that just needs a little traction enhancement and some more oomph for the local hills around town. 3.42's are pretty disappointing, I can't believe they're putting even more anemic gearing than that in many trucks today. 3.23's, 3.08's, etc.

There are a number of other ways they could improve MPG without robbing a truck's torque output.

Do you have the 4L or 6L transmission? What size tires?

I have 3.42s on my 99 Silverado I swapped a 5.3 into. I have an axle I regeared with 4.10 but haven't swapped it yet. My 06 Suburban 2500 has 4.10 and I really like them. But on the lighter 1500 Silverado, I think 3.73s would be a bit better for an all-around gear. This is with the 4L80e on my trucks though and around 31" tires? LT265/75/16

On the 6L you split the OD gears in two, so Abit better.

 

[Doubeleive]

@strutaeng

That's an excellent video. Thoroughly informative yet not too long and drawn out. I've seen it before years ago but forgot how good it was. Looking into a TrueTrac at this point and possibly re-gearing to 3.73's.

I've heard/read many say that's a pointless re-gear - if you're gonna do it, might as well go up to at least a 4.10 - but I think for my application it'll be well worth it.

It's a 2wd DD that just needs a little traction enhancement and some more oomph for the local hills around town. 3.42's are pretty disappointing, I can't believe they're putting even more anemic gearing than that in many trucks today. 3.23's, 3.08's, etc.

There are a number of other ways they could improve MPG without robbing a truck's torque output.

3.73 is snappy enough and you won't loose much on highway drives if anything

 

[07CLASSIC]

Do you have the 4L or 6L transmission? What size tires?

Just installed a beefed-up 4L from Finish Line Trans, to replace the OEM 4L (Very happy with it.)

Roughly 32" on 20's.

I have 3.42s on my 99 Silverado I swapped a 5.3 into. I have an axle I regeared with 4.10 but haven't swapped it yet. My 06 Suburban 2500 has 4.10 and I really like them. But on the lighter 1500 Silverado, I think 3.73s would be a bit better for an all-around gear. This is with the 4L80e on my trucks though and around 31" tires? LT265/75/16

On the 6L you split the OD gears in two, so Abit better.

Yeah, I'm hoping that's what the 3.73's will give me is a good all-around setup.

ETA: Especially with the addition of the TrueTrac.

 

[07CLASSIC]

3.73 is snappy enough and you won't loose much on highway drives if anything

That was my only concern was some MPG loss and possible negative effects on highway. I don't do much highway though so I'm hoping it will be negligible when I do get to travel some in the near future.

 

[strutaeng]

There was this guy on a different forum that had this old Chebby 1500 plow truck. He'd swapped a 14 bolt on the rear and the gear ratio didn't match the front. He only used it inside his property and exclusively for plowing, and he didn't want to mess with backlash, etc. So he ran some larger tractor rear tires and some tiny front tires. It was sketchy, but good enough for his use! LOL

I guess what I'm saying is another way to change the effective gear ratio is by running smaller or larger tires.

 

[07CLASSIC]

There was this guy on a different forum that had this old Chebby 1500 plow truck. He'd swapped a 14 bolt on the rear and the gear ratio didn't match the front. He only used it inside his property and exclusively for plowing, and he didn't want to mess with backlash, etc. So he ran some larger tractor rear tires and some tiny front tires. It was sketchy, but good enough for his use! LOL

I guess what I'm saying is another way to change the effective gear ratio is by running smaller or larger tires.

Interesting. My mind is struggling to understand the logic and dynamics of what he actually did, but I think it would only be right if we all had just enough land to be able to tinker like that all we wanted.

That'd be fun to be able to solve your own problems like that on your own land. So few today can even find enough room at their home to do basic maintenance on their vehicles. I loved working on my truck in the garage in recent years past and now Public Storage moved into our area and bought up all the storage companies and started sky-rocketing everyone's rents 3x/year.

Had to first consolidate two units into one and then ultimately move everything home. It's other fam members' belongings, I don't believe in storage units, but now my garage is filled and a guest room, etc. Wish I had more space. We all could use more.

 

[Doubeleive]

Interesting. My mind is struggling to understand the logic and dynamics of what he actually did, but I think it would only be right if we all had just enough land to be able to tinker like that all we wanted.

That'd be fun to be able to solve your own problems like that on your own land. So few today can even find enough room at their home to do basic maintenance on their vehicles. I loved working on my truck in the garage in recent years past and now Public Storage moved into our area and bought up all the storage companies and started sky-rocketing everyone's rents 3x/year.

Had to first consolidate two units into one and then ultimately move everything home. It's other fam members' belongings, I don't believe in storage units, but now my garage is filled and a guest room, etc. Wish I had more space. We all could use more.

it's just a matter of calculating the math of how many rotations one does versus the other

 

[07CLASSIC]

it's just a matter of calculating the math of how many rotations one does versus the other

Right. My mind started down that road a ways, but I was trying to figure out how small tires on the front would ever cause the front and rear axles to turn at the same rate - then I 'membered he said the rear was a different ratio than the front and my ears started smoking just a little bit.

I guess I didn't have enough of the variables to put the whole picture together, but he did make it clear that his point was that changing the tire size is another way to change the gear ratio. Good point. I know that smaller tires/wheels also equal higher MPG, but not sure any of that would help my situation.

I think 33's are about as big as I could go without a lift and wheel well trimming, but I'm not sure that would help me create any extra torque. If it were that easy though, I'd possibly go that route.

 

[07CLASSIC]

3.73 is snappy enough and you won't loose much on highway drives if anything

What IS the effect on the highway, by the way? Just slightly higher RPM's, right? Going from 3.42 to 3.73.

 

[strutaeng]

Yes, slightly higher RPM on the highway. But it also puts your cruising RPM where you engine is capable of making more power, so throttle response is better and the engine can maintain speed with less downshifting.

Yeah, that guy with the snowplow truck had like 3.42 originally, then swapped a 4.10 rear end. So you just play around with different combinations of OD of tires for the front and the back with those 2 different gear ratios until your RPMs or speeds are close enough using those online calculators.

Like this one:

Spicer Transmission Ratio RPM Calculator

Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.

spicerparts.com

 

[07CLASSIC]

Yes, slightly higher RPM on the highway. Put it also put your cruising RPM where you engine is capable of making more power, so throttle response is better and the engine can maintain speed with less downshifting.

That will be nice. I have noticed that on the hwy hills.

Yeah, that guy with the snowplow truck had like 3.42 originally, then swapped a 4.10 rear end. So you just play around with different combinations of OD of tires for the front and the back with those 2 different gear ratios until your RPMs or speeds are close enough using those online calculators.

Like this one:

Spicer Transmission Ratio RPM Calculator

Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.

spicerparts.com

Ahh. Thank you. That'll be very useful and will sear some figures into my mental tables. Added to favorites list.

 

[Doubeleive]

What IS the effect on the highway, by the way? Just slightly higher RPM's, right? Going from 3.42 to 3.73.

a little bit yes, it's not really that noticeable but pulls better off the line

 

[07CLASSIC]

a little bit yes, it's not really that noticeable but pulls better off the line

Yeah, that's what I'm most interested in. Better pull on hills around town and better towing torque.

 

[07CLASSIC]

Can't find the option to contact the current Mod(s). They moved this thread, which is fine, but the notification ends with ... "leaving link for 7 days".

What does that mean?

 

[Doubeleive]

Can't find the option to contact the current Mod(s). They moved this thread, which is fine, but the notification ends with ... "leaving link for 7 days".

What does that mean?

@Fless @07Burb

 

[Fless]

Can't find the option to contact the current Mod(s). They moved this thread, which is fine, but the notification ends with ... "leaving link for 7 days".

What does that mean?

@Fless @07Burb

It means that if someone looks for the post in the original location, a link there will persist for 7 days, taking the user to the new location of the thread.

For a list of the mods ("Staff") that are currently online, look on the righthand side of the browser window. You can start a "conversation" with any of the mods listed there. Moderators also show a label to that effect under their avatar, so you can "converse" with any of them (but they may not be online at that particular time).

 

[07CLASSIC]

It means that if someone looks for the post in the original location, a link there will persist for 7 days, taking the user to the new location of the thread.

For a list of the mods ("Staff") that are currently online, look on the righthand side of the browser window. You can start a "conversation" with any of the mods listed there. Moderators also show a label to that effect under their avatar, so you can "converse" with any of them (but they may not be online at that particular time).

View attachment 451157

Ah. That makes sense.

ETA: I see what you're saying now about the Mods/Staff online.

Thanks.

 

[07CLASSIC]

So, ... while we're on the topic and all, ... I guess I'll just ask the 'natural-evolution-of-the-discussion' question.

What are the pros and cons of 3.73 vs 4.10? Why shouldn't I just regear to 4.10? Does 4.10 get into less benefits on the highway? Would that be the main drawback for my application?

 

[07CLASSIC]

Can anybody post a link that will confirm exactly which model of TrueTrac will fit my 07 Tahoe LT 2wd 5.3 gas? I thought I had found the 912A556 to be the correct model, but I've had two Fitment Check apps tell me that's not the right model. Looks like the 913A481 is also coming up as the model that fits.

 

[Doubeleive]

can't find my invoice for mine, had 4wheel parts install it. I will probably go by there in a couple more days and see if they will print me out a new invoice.