My rearends spider gears broke today. Punched a hole thru the rearend cover and did some major crunching!

I have been wanting to change to a Locker (I do a lot of offroading and mudding!) and different ring and pinion if needed so nows the time.

I am running a 38.5" tire and auto trans so I think a 4.56 is the way to go?????

Please any advice on the best locker and ring/pinion ratio is appreciated as I need to get the parts ordered ASAP.

I cant afford an air locker the detroits are at the top of my budget.

Thanks in advance!

 

Randys is recomending a Powerlock for the front and rear instead of the Detroit due to the fact that it can be rebuilt and will have better manners on road.

They are suggesting 4.56 with the 38.5" tires.

Anybody have experience with the Powerlock's???

 

You don't need 4.56's, especially with POD's on the way. 4.10's at most, but if the truck has 3.54's, just go with that. You will have plenty of torque to turn the tires when the POD's go in.

 

So you are suggesting I stay with the stock 3.54's?

That would save me some money but I am worried about the ring and pinion in the back where the spider gears came apart. I am not sure how to check them for non visible damage and wouldnt want to reinstall them with the new locker if it might cause damage.

If I am going to have to buy a new ring and pinion set should I go ahead with the 4.10 or stay with the 3.54's? I am going to go ahead and install a locker in the front at the same time so if changing to the 4.10's is the way to go I should do it now.

 

It prolly depends on how the truck is primarily used. You say you do alot of offroading. So does that mean this truck is basically a toy you drive offroad on the weekends and stays parked pretty much the rest of the time? Or do you drive it daily to work and go offroading from time-to-time, say a couple times a month? If it's the former I'd say yeah, move up to the 4.10. If it spends most of the time on the pavement, then I'd say no, stick with the 3.54.

 

It's a daily driver that I take offroad at every oportunity.

The intention thru this whole project has been to build a VERY capable offroad truck that can be used as a daily driver also.

I know it is hard to meet in the middle with that but I would prefer to lean towards the daily driver side of things.

 

The D70 is notorious for the center pin comeing out and ripping everything up with it. You don't need 4:56's with the diesel, like they said. It probably won't be noticeably slower off the line with 3:54's and big tires. than 235's with 3:07 would be. Save the money on the gear and put it towards an air locker maybe, for better driveability on the highway. A full locker is gonna build heat on the highway, especially with big meats on it.

 

I have had a Power lock in both my trucks and they work great. they do what the name says the more power you put into them the harder the spider gears push into the clutches and the better they grab. When you are on the street they allow more slip for corners if you are not hard on the peddle. No harsh locking and unlocking. I would definitely not use a Detroit in the front. With lots of weight and big tires it can be almost in possible to turn at slow speeds under load. Had a friend with Detroit front and rear and it was junk except in a straight line. We put a Power lock and it worked just as good and he could turn. Lockers are also hard on axle shafts if a fast spinning tire finds good traction all of a sudden, a Power Lock will cushion the shock a little. Its up to you but I would say go with a Locker in the rear and a Power Lock in the front with 3.54 and let the low rang in the 205 do its job. 4.10 at the lowest.

 

Yeah, I cannot image how anyone could use gears any deeper than 4.10 under any circumstances. Rock crawler maybe. I put in low range to haul some stuff around the house once and almost needed 4th gear to pull the trailer through there without taking all day to do it.

 

I ordered the Dana Power Lock today and plan on keeping the 3.54's.

After I get this one installed and tested I think I will do the same for the front.

Thanks for the advice!

 

I know you already ordered your stuff but I would never not do the gears with tires that big. With stock gears and 38.5 tires it's like having a 2.95:1 rear end and who wants that? Especially in a 7000# truck. Combine that with the extra weight of the larger tire and the tranny longevity is compromised. If you were to put the 4.10's in it would be like the stock tires with 3.41:1 gears so you're still a little taller than stock. To get back to the stock ratio you would need 4.27:1. Big tires without gears is the number one reason guys in my area are constantly rebuilding trannies. Do the gears.

 

Everybody seems to think that with the torque of the diesel it compensates for the higher gear?????

My truck weighs in at 8500# before the 38.5's so its a lot to motivate with the auto tranny.

I am still waiting on my parts so its not to late to put some 4.10's on order.

I was hoping to get more opinions on this thread to help make a decision.

Anyone else care to chime in???

Remember I am getting ready to put in my POD's also.

 

With any other engine, deeper gears would be a no-brainer, but I'm gonna have to go with the majority opinion and say stick with the 3.54's. Especially with the auto since the torque converter is also a torque multiplier when you're getting up and going. The power-lok is a great idea. Wish I had one--I hate my Detroit

 

With tires that big I would change to 4:10's I wouldn't go any deeper than that though. The pinion gear starts getting pretty small with lower gears.

 

The auto tranny is the number one reason why he should do gears. Our torque converters are in no way a torque multiplier. Torque multiplication, to my knowledge, comes from a stator that collects fluid that would normally deflect off to the sides and not make proper contact with the turbine fins. This results in increased torque transfer. That is a feature of high-end converters and certainly not found in a stock one.

What is everybody's reason for wanting to see stock gears stay? With a non lockup converter and 38's combined with your new effective gear ratio of 2.95:1 you are not going to see increased fuel efficiency. All you're going to see is a torque converter that is constantly spooled up more resulting in increased tranny temperature. Your foot will also have to be in it more to maintain any given speed which will negate any advantage you might have had from the high gears. I'm willing to bet that you'll get better mileage with the 4.10's. As I previously stated 4.10's will still be taller than stock a little. Not getting the gears is penny-wise and pound-foolish.

Somebody else please chime in and help me out. I'm outnumbered here.