Calling all 4.10 Users

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GregH

Well-known member
Apr 24, 2004
1,630
0
The rear diff in my '89 RRC is starting to make noise and it appears that a change is going to be needed in the near future.

Before I make my contribution to the Bill Davis Retirement Fund, I'm looking for some advice.

First of all, when I pull the third member I intend to upgrade to rear locker and HD axles.

My question is how beneficial do those of you with 4.10 R&P feel it has been? Of course, if I change to 4.10 then I'll be pulling the front diff and doing all the upgrades (TT with axles and latest bling GBR CV's as well) and dropping some $$.

I'm sure that I'll notice the additional off-the-line increase and probably actually get above 30 MPH climbing to Big Bear (my kids wave to the bicyclists now as they pass me with 3.54's ;) ) but has it been worth the money to you especially offroad?? BTW-I run 265/75's

Thanks-
 
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Kyle

Guest
After having the 4.10s for over 100K in the big truck my feelings are mixed. Before I get into it I will say its the cheapest power that you will ever buy. However , driveline speed has alot to do with how your vehicle feels and drives. Witht he 4.10 I feel its overly increased. I am thinking something along the lines of a 3.7 or 3.9 might be a better choice. I read somewhere in another post that they are available in those ratios from someone in the UK. The rangies I have will outrun the Discoveries that I have so I am also thinking that the 3.7 or 3.9 will be plenty of gear for the rangie..

My end all be all advice would be to squeeze a little more out of the motor and go with a 3.7-3.9 gear ratio. That should give you good highway manners and nice smooth power...
 
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DiscoDino

Guest
Are the 4.11s and the 4.10s different? I seem to have been reading that for a while...KAM has a new website, although, after searching, I got to the old one posted above.

Hey Kyle...if you go the Toy route you can have a choice of up to 13 ratios (teasing...teasing... :D )
 
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Kyle

Guest
lol , Sorry Nadim but if I ever felt the need it would be a 9"............ You are aware that differnt ring gear diameters are more efficient then others right ?
 
Eric N.

Eric N.

Well-known member
Apr 20, 2004
3,980
0
Falls Church, VA
I would assume that the 3.8 would be a little stronger then the 4.11-4.10 wouldn't it? Sounds like a win-win to me..
 
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Kyle

Guest
You would have to do the math but I am betting that the 3.8 will put you right where you want to be with a 32......
 
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PHARAOHDISCO

Guest
I drove for a few months with 32" tires and 3.54 gears. The Disco had really very low torque at high speeds and the acceleration was terrible. On highways I even had difficulties going over 70 mph or even reaching that speed level. The minute I changed to 4.1 gears, I was impressed. The Disco was even more powerful, than with stock tires and stock gears. Acceleration and torque have improved. Top speed is again about 90 mph, but I wouldn't try to drive at that speed. 75 mph on the highway is currently a very comfortable speed. Go with 4.1 gears or even 3.9. Ashcroft Transmissions in the UK do them. I bought my gears from them.
 
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Kyle

Guest
There is no doubt that power is increased big time with the 4.1's in there. The down side is that the truck is too "Busy" at speed on the highway. Just short trips arent bad but when you do a few thousand miles at a clip it wears on you big time. Also the Land Rovers are Plagued with Vibrations , with the 4.1 you just increase an already known issue. In my mind you want to keep engine and driveline sppeds as close to stock as you can get. Yeah , stock wasnt really all that strong but the classic rangie is a fairly strong truck to start with. They will outrun a Disco in a heart beat.. As I said , I think the perfect combonation is the 3.8 and a little engine work to give it a little more torque. I am wanting to say the gears and a cam/chip change would put a big ass smile on your face and you wouldnt suffer for it on long trips..
 
Discojunky

Discojunky

Well-known member
Apr 20, 2004
384
0
62
Greenville SC
Greg,

I have had the 4.11's with 255/85's for almost two years and I love em'. I'm sure you will get all kinds of replies and thats a good thing but remember that its all just information for you to use to make the best decision for you. How much highway use, what kind of trails... should come into play. But if your talking about lockers, axles and gears I'm thinkin' your pretty serious about offroading and are not going to use this as a commuter. So, go 4.11 and lean more towards offroading and you'll be happy. I drive about three hours to go to most of the GOOD places around my area to four wheel and I feel very comfortable with my setup on and off road and wouldn't change it for nothing.
 
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DiscoDino

Guest
Kyle...

I'd like to see them 9"s when you need them... :D

I know that ring diameter is key...but I also know that a hypoid design is far stronger than the similarly sized ring gear...

on some BBs, the 9"s and the Toy 8"s have the same limits as far as the total axle assembly is concerned...not sure about the ring and pinion though...
 
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rtiqulatendisco

Guest
I run stock gears and 255/85 tires. I went with the 4.6 upgrade and am happy with the power. Next is a good cam. Other than RPI, any one make a good cam for a D1 with a 4.6?
 
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Kyle

Guest
Yeah , thats more or less what I am talking about. a 3.5 isnt exactly a small gear. the trucks just dont have any power.. You should jump up to the 3.8 yourself , I am betting that would be sweet as hell.... YOu would end up with the power and road manners of a stock P38 and still running big tars..
 
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GregH

Well-known member
Apr 24, 2004
1,630
0
Kyle-

Are you running a stock 1.2 ratio LT230 in your D1? My BW/TC is running fine now but you never know...

With that 3.8 R&P, a 4.6 shortblock and modded (stock high/crawler low)LT230 I might be getting the best of all worlds.
 
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gadams

Guest
I just put 265/75s on my D2. When researching, I saw that the change from the stock tires (255/65) from a gearing standpoint (not sure the correct term, higher ratio?) was about 10%. Bill at GBR says the 4.10 is 12.5% lower ratio than stock 3.54. That would seem to put you pretty close to stock ratios once you are done. No doubt the vibe issues get old on long trips but after reading some of this other stuff about how higher revving is actually good for these engines, seems to me we ought to all be changing to 4.75s and building new seats out of Sorbathane. :D

Greg
 
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GregH

Well-known member
Apr 24, 2004
1,630
0
According to that KAM website, the 4.10's are a 14% decrease from 3.54 and the 3.8 is a 7% decrease. That puts the 3.8 slightly closer to returning to your quoted 10% increase due to tire size.
 
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Kyle

Guest
For what its worth. With 4.1's and a 34" tire you are still under geared quite a bit... And Greg , there is a sweet spot with these engines at which point your fuel consumption really takes a dive. You will hear the engine change pitch. The 4.1s dont really allow you to run long distances at speed and stay out of that zone. Its been so long now since I drove that truck but I want to say it was around 67 MPH wearing the 34s...
 
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