Advice on 5.38 Gears for a Trail Bronco, Too Much?

[Prizefighter]

I have a set of full width 44/9 that I removed from my big Bronco before I sold it to go under my '77 Bronco that is used for off-road only. The axles are built up with chrome moly shafts, spools, 5.38 gears. I plan to run 37s. Too deep of gearing? I don't want to run the spool in the front so I will have the chance to change gearing in the front when I have a Detroit Locker installed and changing the rear 9 shouldn't be hard for the guy doing it.

A bit more info on the Bronco: 300 HP 351W, C4/D20, 37s on beadlocks. Thought about going with a C6/205 since the C4 could use a rebuild. The 205 won't have as deep gearing as the D20 so the 5.38 could be useful.

Appreciate the advice!

 

[garberz]

Your low range crawl ratio will be 30:1 with the D20, or 26:1 with the 205. It certainly won't be too low for out on the trails. Mines at 42:1 and the low range is still fine for keeping a decent pace without constantly shifting back to hi range. And with 37's it's even less low gear than my 35's. I'd just put in the Detroit and call it good.

Mark

 

[rjrobin2002]

That's 2687rpm at 55mph, so I say go for it.

 

[broncosbybart]

The only drawback to the 5.38's is the pinion size. That said, the D44 axle shafts seem to be the weak link anyway.

I had a rig with 5.38's and a 351w/435 trans and liked it. The C6/205 will need all the help it can get for crawling.

 

[Seventee]

I like deep gears so my vote is to stick with them.

 

[Prizefighter]

That's 2687rpm at 55mph, so I say go for it.

If this Bronco goes 55 that would be sweet. Scary too.

 

[needabronco]

As easy as a C4 is to rebuild, why swap a C6 in? Seems like more work and not a huge benefit?

 

[rjrobin2002]

I built that Bronco I got from you with 5.13s and 38 TSL Radials and could not believe how well it drove at 55 mph in 3rd and 70 mph in OD. The key is alignment and tight steering. Too many people don't make enough effort to eliminate steering slack and get good alignment numbers.

I just did my RPM numbers and I run 2697rpm to work every day running 35s, 4.56 gears and C4 and drive 60mph to work. I grew up on ATVs and not diesel tractors, so I don't mind some RPMs.

 

[garberz]

.....I just did my RPM numbers and I run 2697rpm to work every day running 35s, 4.56 gears and C4 and drive 60mph to work. I grew up on ATVs and not diesel tractors, so I don't mind some RPMs.

I have that same gearing and run 60-65mph all day long. I love the simplicity of the C4

Mark

 

[Broncobowsher]

Last time I saw 37s with 5.38 axles it still wasn't a happy trail rig. Diesel, 6-speed auto and a stock late model transfer case. Still always on the convertor making the transmission hot. That is a transmission with a lot lower 1st gear and lower transfer case gear then any of the options you are looking at.

I am going to say you won't have enough gear.

 

[ntsqd]

I'd hang a lower geared than stock Atlas under there before I'd hang a C6/205 combo under it.

 

[Prizefighter]

Sounds like I need to avoid the C6/205. It was an idea I had since the C4 needed a rebuild and a buddy has C6.

If you can't tell things can snowball with my builds - going to stay the course then and keep it simple. Swap in the full widths with the 5.38 and rebuild the C4.

 

[rjrobin2002]

Get the low range dana 20 gear kit if you want lower gears. Or upgrade later to a ZF or 4r70w with lower first and lock up converter.

 

[edones06]

I run them with a doubler and i love them.

 

[Prizefighter]

I am going to run them, kicker is with 40s. There was a rebuilt C6/D20 with a Bronco I bought so will run that combo too behind a 351W. OCBR is coming up this September so I'll report back. Should be fun

 

[NYLES]

Get the low range dana 20 gear kit if you want lower gears. Or upgrade later to a ZF or 4r70w with lower first and lock up converter.

Impress me and tell me where I can get some Dana20 gears?

 

[ntsqd]

Impress me and tell me where I can get some Dana20 gears?

http://www.wildhorses4x4.com/category/Bronco_Atlas_Transfer_Case

 

[Broncobowsher]

Impress me and tell me where I can get some Dana20 gears?

Teraflex is the manufacturer
You are looking for the TeraLow gears for a Bronco Dana 20 transfer case.
Many retailers out there. The first Bronco supply house that I found with them is http://www.wildhorses4x4.com/produc...er_Case_Gears_Kit/Bronco_Dana20_Transfer_Case

 

[Broncobowsher]

There is another source of gears, as low as 4.86. I forget the name. But for the price of those gears you should just get an Atlas.

 

[NYLES]

There is another source of gears, as low as 4.86. I forget the name. But for the price of those gears you should just get an Atlas.

That's still not a bad route those are low enough to think about putting a auto back in it.