Since recently installing 4.75's in my D90 (from 4.1's), I have noticed and interesting difference. When in low range, in drive, at idle, the thing is really pulling on the brakes. It really wants to go forward and crawl. It takes a fair amount of brake input to keep it from creeping forward. Once the 38's go on, I will be back at around the same ratio I had before. But I wonder what a low gear set for the t-case or a crawler box might do to this situation. Might be a real bear to keep it from moving on its own in low range. Any thoughts? The truck drives and runs normally otherwise (about 700 rpm idle). It has always had pronounced engagement of drive or reverse.

Blister

You crawl ratio is with 4.75s an Lt230 and a ZF autobox is 39.11. With 4.11s is 33.84. Even though it doesn't sound like a lot, it is a huge difference. I ran 4.70 for a while and I experienced the same thing with only 33" tires. One trick for areas like farmington and similar is to put the auto in neutral while decending. This makes it so that there is less pull on your vehicle. You probably know everything I already wrote, but have you thought about putting bigger brakes on?

Way

Originally posted by BillnSandi
Once the 38's go on, I will be back at around the same ratio I had before.
Blister

SAY WHAT!? Dude, are you moving your front axle forward? After seeing Mr. Addictions 37's stuffed it looked like that's all your gonna' fit and still clear the bulk-head outrigger...Of course it's not that hard to remove that fat pos!

--D

are you sure you wanna stick with the rover diff? I know guys that have sheared pinions with lesser tires.

Bill and I have both trashed R&P sets with lesser tires and yes, I do occasionally rub my outrigger with my 37s. It should be interesting to see how Bill deals with these problems. The R&P should be better since he's got the new special treated R&P sets from GBR. I'm waiting on the treated 4.11s which should be theoretically stronger.

I do think that it would be possible to crank the 3-link links out at least 1/4 inch longer to move the axle foreward just a little. That might be enough to allow enough clearance. Just watch the panhard rod and tie-rod. 1/4 inch shouldn't mess with the springs or shocks too much.

-John

Oh yeah, and back to your question Bill, I've heard some of the toyota guys talk about not being able to stop the truck with the brakes when you have silly low. I think this is a function of the brakes needing to overpower the creep of the autobox and now having so much more reduction for the creep to act with. Probably not noticed so much with a manual tranny since I just push in the clutch, but I hear that with silly low you can't stall the engine with the brakes even in a panic situation. Gotta remember to push in the clutch or use the key to kill the engine. Kinda makes you want to put in an emergency kill switch somewhere accessable, huh? I guess in your case though, you'll just have to throw it into neutral when you stop.

-John

Bill,

The low gear creep with an auto box is common in most vehicles, especially when the vehicle has not warmed up. However, everyone I know seems to adjust to it and enjoys the extra control the lower gearing gives.

Rich

bill and john, have you considered the toyota center diff? i'm guessing you want to keep you present axles so you don't have to mess with custom brackets, wheels, brakes, and all the other stuff associated with axle swaps. anyway, just a thought...

Originally posted by Rover Addiction
I guess in your case though, you'll just have to throw it into neutral when you stop.

-John

Give me a fawkin' break guy's! Just push on the Gurd Durn peddle a little harder! Sheeze you knuckleheads are soundin like you have 200:1 with a high hp!

Or are you actually saying that you can't stop your rigs w/auto's anymore with your supper low 4.75's and 11" four wheel disks?!!


:flipoff2: :flipoff2: :flipoff2:

Originally posted by alhang
anyway, just a thought...

Yea...Good one too! :rolleyes:

toy diffs are the only way to keep the stock housings and run a better than stock setup(that i know of). you get more gearing choices,keep the droput center section, good choices in lockers, and better ground clearance than going with a one of the bigger dana's or ford 9. they will also hold up to 38's with ease, a local guy has been running them for over a year with no problems.

Yes, but the issue has to come to the point of diminishing returns...A Jack Mac housing (Toy filled and drilled to the rover housing bolt pattern) costs about $400 + shipping (or do it yourself for less). Then you need gears...Then set-up...Then "supper" bierfeilds...I'm not even sure if the RD56 ARB fit's in the Toy housing...And I'm not sure about the inner axle length if the RD56 doesn't fit the Jack-Mac/Toy housing.

The point is that with the money spent putting together a Rover housing to get close to the strength of a D44 you could have had a 60 cut down to your specs...Lest we not forget ALL of the HUNDREDS spent on fixing/replacing all the broken crap that got us to the point of considering replacing the center sections, cage stress-riser smoothing, cryogenics', ring-gear polishing etc...

Hell, it's really not that hard to do it yourself, (build a 60, 44 or 101FC) and it's fun! Just ask Adam, Sam, Mike, etc...Why not go "bullet proof" once and for all?

Let's see…Junk yard 60 say…$900….Cut down….$400….Axles….$300….Locker (ARB) $650…Gears…$200…Set-up w/bearings…$300….We are at $2750…Now either you and a friend can adapt the rover stuff to the 60 for price of some .25 A36 plate and strap, grinding wheels and some gas…So assume around 3K for a 60 front…Now ask yourself what kind of wheeling you want to do, how often you've broken, and do you want to continue to chase the holy grail as trails get harder and harder? Do you want your rig to run "mild" trails? Or does "extreme" turn you on? Ever want to run Upper Heldo, or Proving Grounds? Do you want a buggy? Can you fathom putting one together?

I, as many have noted over the years, love my 90 (what's left of it) and, as such, am going hole-hog on the build up…Why? It's fun! And as Camo put it so well…I want to be able to drive over things you can't!

Sheeze...Can you tell I don't want to work on this report that's due tomorrow? :rasta:

--D

D, i totally agree with you, but I thought the goal was to keep their stock housings. Anyway, I think my friend did the conversion for under 900(complete diff, toy e-locker, housing, custom axles) for the rear(local mechanic, i have no idea how he gets his deals). I believe the front was less, but he seems to pull deals out of a hat. I talked to Bill a while back on getting improved parts and we talked about the pro/cons of metal treatment. I think he mentioned metal-lax and cryo forging but I always considered that to be the equivalent of engineering voodoo.

right now, my goal is to keep stock housings, diffs, brakes, and hubs. I would like to keep bolt-on parts interchangability between my two D90s and my D110. That way, I can stock one set of spares and keep things consistant.

Yes, I'd love to build an indestructable setup in my D90 and actually for all of them. However, right now, this is an easier way to go for me. I actually have an old chevy pickup that I'm thinking about making into a buggy that already has a good running 350, TH350 tranny, NP208 t-case, NP205 sitting on the garage floor waiting for a doubler someday, and a 14 bolt with a detroit. The weakest part I see about this thing is the 44 front although that can be either upgraded or directly swapped for a 60. And the body is complete crap so I don't care about it at all. I'm thinking about trashing the body, shortening the frame a bit, setting up cross-over steering, and then a good roll cage with some rover panels hanging on it. I can still register as a chevy and pass smog and then have a rock buggy that I can beat up and not worry about. Oh yeah, and I've got a grand total of $2300 into it and the most expensive part about it is the 4 new 36x12.50 SXs it's currently sitting on!!

So.... does that make sense to anyone else, or am I just crazy??

Maybe ideally, I'll do some 101 FC axles under my D90 someday, but for now, this seems to be the way to go.

-John

Of course, the down side to all of that is that I'll probably get kicked off of the rover forum and end up having to socialize with some chevy guys! :( :flipoff2:

hey bill, you mean that you havent noticed the same thing with the 8.1 amd auto in the tow rig? cause in the Burb with the 7.4, auto, and 4.10s on 265/75s, you can tell its trying REALLY REALLY hard to creep through da brakes!! :D

Ron,

I think you already are hanging out with the 'Chevy guys', you just don't know it. ;)

Anyway, Bil....

The torque converter in your autobox is engaging prematurely at idle.

Steven had this problem in his bob-tailed RR (350/Turbo400).

He ran Rubicon with his left foot on the brake and his right foot on the gas.

Result: Grenaded axle shafts (custom = $$$$$$) and now is looking at a D60 front axle.

I would advise to re-think your torque converter and look for one with a higher stall speed (I think that's the term??) If you don't you'll be looking at some serious cash spent on CV's. Steven's axles are the same ones I have in the Serious One running UJ's and they're lots stronger than the LR CV's (and he still managed to break them).

Anyway, my .02 cents....

Michael

CTMs

:)

Ron (I think you meant to say John though above)

Yeah you're right! ;)

Anyway, the CTM's will go in the front axle of the Serious One when I do the freewheeling hubs on all four hubs later this spring/summer. Hopefully it will allow me to sleep easier at night.

Hehe.

Michael

Originally posted by Serious One
Ron,

I think you already are hanging out with the 'Chevy guys', you just don't know it. ;)

Anyway, Bil....

The torque converter in your autobox is engaging prematurely at idle.

Steven had this problem in his bob-tailed RR (350/Turbo400).

He ran Rubicon with his left foot on the brake and his right foot on the gas.

Result: Grenaded axle shafts (custom = $$$$$$) and now is looking at a D60 front axle.

I would advise to re-think your torque converter and look for one with a higher stall speed

Michael

NO NO NO!! Don't do it! One foot on the break and one on the gas is okay as long as it's used for speed modulation...If your torque converter has too high a stall your gonna' be lugging up a ledge..then launching over it at a higher rpm...With a low stall you can just drive with your left foot! I don't know why Steven had to use both, and I don't know the driving char's of Steve's 350/T400, but typicaly with the low hp LR 3.9 lower is better...Unless your running supper low gearing...Which Bill is not.

The u-joint let go because it's a 297x u-joint on a RR! Gonna' happen. Again CTM's all the way baby.

--D

D-

You are absolutely correct. But, I think Steven's problem was that if he didn't have his foot on the brake HARD, the car would drive away even at idle. It was a big enough problem that it eventually stressed the UJ's and shattered them.

You are correct though (Bill, listen to D, he knows the SH%#).

Later,

Michael

On thing I would consider trying in the rocks (I did when I had a standard) was to use the e-break rather than stepping on the peddle...Stresses only the output shafts of the t-case rather than the stubs, cv's, axles, ring, pinion, yoke, DS and t-case outputs...

Can't do that all the time, but on those optional straight forward ledges it's not hard to do...

--D

the e-brake thing sounds like a plan, but I do have a question: What are the wear characteristics of our rover e-brakes? I've never had to rebuild or replace one, but if you drag your e-brake on a consistant basis, will it come apart?

Just curious. I have occasionally used mine to slow my rig just to see how it would work and it works ok, but I was always told that this is a big no-no.

-John

I avidly use mine, and I haven't broken anything. I have to adjust the e-brake frequently though. as it gets loose. I think that if it is used only when wheeling and parking. You will be fine. The thing is pretty massive.

Way

Sounds good to me. I'll keep that in mind. I haven't had to adjust my e-brake in a long time so I guess I haven't been using it enough. :D

-John

Originally posted by BillnSandi
Since recently installing 4.75's in my D90 (from 4.1's), I have noticed and interesting difference. When in low range, in drive, at idle,

But I wonder what a low gear set for the t-case or a crawler box might do to this situation. Might be a real bear to keep it from moving on its own in low range.
Blister

Hey Billster!,
With the crawler box engaged I have to really step on the brakes! to keep her from walking, she needs a choke collar I guess, typical Rover :D

Sorry I've been so Quite! I'm getting ready for a possible move to San Diego after some worldy travels!

TomW