[TorqueO]

Just posting to maybe help out others, wondering what gears to try for 35" tires. Give them some personal experience.

Just put some new tires on, Falkland AT 35"x11.5x15 tires on OEM 10 hole wheels/rims. I have 4.10 gears with Detroit true tracs. The rpms are not bad, they are close to normal. Little 302 with a E4OD, four wheel drive, and a 2 1/2" lift. The rpms r just under 1500 at 55mph.

Had the wife drive long side of me to check my speed. Speedometer is ten miles off. Going to do it again with a friend with a friend this weekend just to be sure.

On a side note I still might go with 4.56s. My personal thinking is if I'm back at or close to OEM rpms, my towing and meeting off roading obstacles (hills, small/shallow river crossing or logs, etc.) would be the same as 3.55s with 31s.

Would I be right in this?

If I'm wrong please let me know. This is my daily driver/ work truck n every now n then a fun toy.

 

[Burntoutaccountant]

I bought 4.88s - found a good deal on yukons. I almost did 4.56s.

I don't have them installed yet but I think you'd be ok.

Check amazon and price match through summit.

 

[packagerjr]

I would probably do 4.88s too. I had 4.56s installed in a 2003 F-150 with 35s and the 5.4L engine.

35s will be a bit heavier so the drivetrain may appreciate a little extra gear.

 

[Stevo440]

Here is a chart that should help you make up your mind.

 

[Gunfixr]

That chart tells me either 4.10 or 4.56, depending on which side of factory you want to be.
But, always, usage dictates what's best.

 

[CrazyBRONCOguy]

I agree on the 4.88 comments. Especially with the 302 as it makes a bit more power higher in the rpm. AS in it likes to be a little higher in the rpm to be in the optimal power curve sport. In comparison the 5.8 makes its torque sooner and would likely be happier at a little lower rpm (tho 4.88's would not hurt it any either).

Backwards maybe, but if you have access to some 275's or 31's bolt those up and take it for a spin and see what you think, be easy way to tell you what direction is the right way without taking the diffs apart and buying gears and stuff.

 

[wileec]

Agree with the 488 the 302 is happier at higher rpm. I ran 456 with 33s ion my old one. Now have 456 on 35s and could do more. Spending money for just a little bit seams like a waste.

 

[BigBlue 94]

4.88 with an overdrive trans.

FWIW im running 37s on my superduty with 4.10s. Its a dog compared to 35s. I loose speed on long hills and have to downshift.

 

[Agar426]

Agreed 100% on 4.88s with OD trans. You stated it's your daily driver. If that entails lots of high speed miles, then you would be in good space with 4.88s. If most of your driving is at less than highway speeds, I would even consider 4.88s with a C6 transmission, or manual without an OD. I have 4.56 gears in my '85 CJ-7 with 33s, and it rarely gets on the highway, and never on the interstate......and it's awesome. Around town and off road, it's amazing. Now granted, I keep my speed pretty mellow on the highway due to it being a CJ-7, and not because of the gearing. In my '85 Bronco, I might tend to have higher speeds, so that's where that OD tranny comes in handy. The 4.88s will also help with compression braking, lugging, etc, etc.

 

[TorqueO]

Thanks for everyones input! This was quite helpful.

I now know the 4.09/4.10 gears and 35" tires bring it back to stock OEM rpms (or real dang near it), for a 302 with an E4OD. I'm going to do a learning experience. I just picked up 4.56's front and rear and will get those installed in a few weeks and then report back here.

Question...... why is Yukon 4.56 R/R front gears so light, while the Motive 4.56 rear gears are much heavier? Making me question if this set of Yukon gears is built right. Never had gears that were so light.

 

[BigBlue 94]

Thanks for everyones input! This was quite helpful.

I now know the 4.09/4.10 gears and 35" tires bring it back to stock OEM rpms (or real dang near it), for a 302 with an E4OD. I'm going to do a learning experience. I just picked up 4.56's front and rear and will get those installed in a few weeks and then report back here.

Question...... why is Yukon 4.56 R/R front gears so light, while the Motive 4.56 rear gears are much heavier? Making me question if this set of Yukon gears is built right. Never had gears that were so light.

Different alloy? Also, some 4.56 and numerically higher gears for the D44 are thin cut or thick cut, depending on what carrier they were made for.

 

[jfourdyce]

I had 35s on my 89 5.8 C6 with 4.56 gears and Detroit TruTracs and is was for the most part inoperable at highway (75 mph) speeds. 3400 to 3600 RPMs to maintain that speed. Way to much twist on my opinion for that truck.

 

[BigBlue 94]

I had 35s on my 89 5.8 C6 with 4.56 gears and Detroit TruTracs and is was for the most part inoperable at highway (75 mph) speeds. 3400 to 3600 RPMs to maintain that speed. Way to much twist on my opinion for that truck.

Thats the fault of the C6. No overdrive kills it. My 85 has the same issue with the NP435 but i have 37s with the 4.56s. Cruises at 3000 rpms at 70 mph. I get 12 mpg pretty much however i drive it. If i had overdrive, i would want 5.13 gears.

Hell my 96 f350 has factory 4.10s and 33s with a c6. It too is at about 3000rpms judging by ear.

 

[TorqueO]

Different alloy? Also, some 4.56 and numerically higher gears for the D44 are thin cut or thick cut, depending on what carrier they were made for.

awh shoot! Don't tell me I got the thin cuts. Makes sense though. I've heard of light weight gears before, for racing, but if Yukon is making a D44 R/R gears for a 4x4 off roading vehicle why the heck would they make it light weight!? We ain't doing the quarter mile in four wheel drive through dips, rocks, mud, etc.

My carrier is Eaton Tru Tracs for 3.73 and up.

Now I have to find the regular cut (if there is such a thing) gears. Lots of learning being done here. Hope this helps others.

Picked these up.....

Yukon Gear & Axle (YG D44R-456R) High Performance Ring & Pinion Gear Set for Dana 44 Reverse Rotation Differential, dana 44r in 4.56 ratio reverse rotation (amazon.com)

 

[BigBlue 94]

awh shoot! Don't tell me I got the thin cuts. Makes sense though. I've heard of light weight gears before, for racing, but if Yukon is making a D44 R/R gears for a 4x4 off roading vehicle why the heck would they make it light weight!? We ain't doing the quarter mile in four wheel drive through dips, rocks, mud, etc.

My carrier is Eaton Tru Tracs for 3.73 and up.

Now I have to find the regular cut (if there is such a thing) gears. Lots of learning being done here. Hope this helps others.

Picked these up.....

Yukon Gear & Axle (YG D44R-456R) High Performance Ring & Pinion Gear Set for Dana 44 Reverse Rotation Differential, dana 44r in 4.56 ratio reverse rotation (amazon.com)

From my understanding, there is regular thickness for the 3.92 and up carrier. Then there is a thick cut for use with the under 3.92 carrier.

 

[paul rondelli]

With the 302 and stock size tires...... you could get in the 13mpg to 15mpg range......with a little work

Once you go 4:56 and 35" inch tires ...... you will be lucky to get 9mpg.

5 or 6 MPG loss is no joke.... especially if you put in some miles on a regular basis.


Not a big deal for a weekend toy ... but if you start towing with that set up ..... it could get as bad as 7 or 8 mpg.

when I did the 6 six lift, with 35" inch BFG mud terrains, I did the 4:56 swap and added a Detroit locker to the rear of my 1993 Bronco.

My 1993 does have the 5.8 ..... but if you never have owned a single digit MPG vehicle ... it will be an eye opener.

I was definitely not prepared for the drop in MPG


You start doing the math in your head ... and it really sucks

I have a 1993 Bronco that gets 9mpg.... a 1996 Bronco that gets 15mpg.... and a Ford Fucus that gets 31


For the same 50 mile round trip

The 1996 cost half as much to drive as the 1993
The Focus cost half as much as the 1996

 

[BigBlue 94]

With the 302 and stock size tires...... you could get in the 13mpg to 15mpg range......with a little work

Once you go 4:56 and 35" inch tires ...... you will be lucky to get 9mpg.

5 or 6 MPG loss is no joke.... especially if you put in some miles on a regular basis.


Not a big deal for a weekend toy ... but if you start towing with that set up ..... it could get as bad as 7 or 8 mpg.

when I did the 6 six lift, with 35" inch BFG mud terrains, I did the 4:56 swap and added a Detroit locker to the rear of my 1993 Bronco.

My 1993 does have the 5.8 ..... but if you never have owned a single digit MPG vehicle ... it will be an eye opener.

I was definitely not prepared for the drop in MPG


You start doing the math in your head ... and it really sucks

I have a 1993 Bronco that gets 9mpg.... a 1996 Bronco that gets 15mpg.... and a Ford Fucus that gets 31


For the same 50 mile round trip

The 1996 cost half as much to drive as the 1993
The Focus cost half as much as the 1996

Did you recalibrate your speedometer? Or calculate the difference in tire circumference?

Gears and tires should not make that much of a difference. Hell i ran mine at 75 mph @3000 rpms for 1800 miles (6" lift, 4.56, 37s, no OD) and got 12 mpg. Thats with a heavily built 300 with a 4bbl carb. Coming down from the rockies into KS, i got 14 mpg. At close to 7500 pounds.

Throttle position plays a big part. At 3000 rpms, i could use a feather on the pedal as cruise control. And going up hills requires barely opening the throttle. Those same hills require 50% throttle at 2000 rpms in an overdrive equipped truck of similar weight. Thats a lot more fuel.

 

[wileec]

You did not say how the 96 is built. 15 MPG would be great

 

[wileec]

Did you recalibrate your speedometer? Or calculate the difference in tire circumference?

Gears and tires should not make that much of a difference. Hell i ran mine at 75 mph @3000 rpms for 1800 miles (6" lift, 4.56, 37s, no OD) and got 12 mpg. Thats with a heavily built 300 with a 4bbl carb. Coming down from the rockies into KS, i got 14 mpg. At close to 7500 pounds.

Throttle position plays a big part. At 3000 rpms, i could use a feather on the pedal as cruise control. And going up hills requires barely opening the throttle. Those same hills require 50% throttle at 2000 rpms in an overdrive equipped truck of similar weight. Thats a lot more fuel.

Remember that it was all downhill after you got past the divide

 

[BigBlue 94]

Remember that it was all downhill after you got past the divide

Thats why i said i got 14 on the way back! But it is uphill both ways to moab... And down hill lol. Over that entire trip of 2000 miles, i averaged 12 mpg.