Lets talk about ring & pinion gears

[Yorker]

Are the ratios for first and second gears correct? Also what years & models LR & RR used this box?


Thanks

whoops there was a typo
1st is 2.480:1

I'll fix my original post. This is from the RR workshop manual, IIRC the Disco used the same Transmission and the same ratios at least until the late 1990's. Then they used the ZF4HP24 (at least with 4.6l V8) which I don't seem to have the ratios for...

I think '87 was when the ZF4HP22 replaced the TF-727 in RRs, it was adopted for the Disco in Sept, '92.

[edit]

The 4HP22 is a 4-speed longitudinal automatic transmission for passenger cars from ZF Friedrichshafen AG. Introduced in 1980, it was produced through 2003 and has been used in a variety of cars from BMW, Jaguar, Land Rover, Maserati, Peugeot, Porsche, Lincoln, Austin, and Volvo.

Applications:

* 4HP22
o 1980–1982 Lincoln Continental V8 5.0L
o 1981–1987 BMW E28 528e M20/B27
o 1983–1988 BMW E30 325e M20/B27
o 1983–1985 BMW E28 524td M21/D24
o 1983–1984 BMW E28 533i M30/B32
o 1983–1989 BMW E24 633CSi M30/B32
o 1983–1984 BMW E23 733i M30/B32
o 1984–1985 BMW E30 318i M10/B18
o 1984–1987 BMW E28 535i M30/B34
o 1984–1992 BMW E23 735i M30/B34
o 1986–1992 BMW E30 325i M20/B25
o 1986–1993 Volvo 740 2.3L
o 1986–1991 Volvo 760 2.3L
o 1987–1991 BMW E30 325ix M20/B25
o 1987–1993 Jaguar XJ40 3.6
o 1987–1997 Jaguar XJS 3.6
o 1987–2002 Range Rover 4.0L
o 1987–1996 Peugeot 505 2.0
o 1987–1996 Peugeot 505 2.5
o 1987–1996 Peugeot 505 2.2
o 1987–1989 Peugeot 604 2.5
o 1988–1990 BMW E34 525i M20/B25
o 1988–1993 BMW E34 535i M30/B30
o 1988–1992 BMW E32 735iL M30/B35
o 1988–1997 Maserati Biturbo 2.5 V6
o 1988–1997 Maserati Biturbo 2.8 V6
o 1991–1995 Volvo 940 2.3L
o 1992–1999 Land Rover Discovery 3.9L
o 1997–2002 Austin Tempest 4.0L
o 1999–2003 Land Rover Discovery Series II 4.0L

 

[revor]

There are a billion online tire and ratio calculators out on the intertube.. Some of them even have LR ratio's.

I can tell you for a fact that at 5000+ feet 4.1's will be okay for a 235/85
(31.5ish) although the revs at 75 are going to be high! On 33's it will be a bit better (likeable for a stock engine) 35's are back to stockish ratio.

Unless you go 35-37" tire 4.7's are silly.. You will vibe yourself out of the car on the highway.

Do the math with various diameters and ratio's. You will see that LR changed the t Case ratios to get various results. 1.0:1,1.2:1,1.4:1,1.6,1 are all coiler ratios used as UNDERdrives to lower the final drive from 1:1.
Figure the overdrive at .75 (avg) an do the math.
1x1x3.54=3.54:1 Final drive. .75X1.22X3.54=3.2ish, .75X1.4X3.54=3.7ish

 

[UnfrozenCaveman]

monkeyboy, Do you happen to know off hand what your rpm's are at 65mph?
Aren't 235/85's & 245/75's about the same dia.

If you were to do it over would you have gone with 4.75 gears?

RPM @ 65 ~2800...remember that I rarely know exactly what my speed is between the tire and gearing changes. Yeah, I know that's what the gps is for...I just don't care.

From the Tire Rack site... 235/85 BFG A/T dia = 31.7" while the same tire in a 245/75 is shown as a 30.5" diameter. Looks like ~5% increase in circumferance to me.

Would I go with the 4.75's? Nope. For the minimal amount of time I spend at highway speeds and over 5k feet simulaneously, the 4.10's are great.

Okay, calculator at hand today:

o.e. = 3.54*1.22 = 4.32
r/p chg to 4.10*1.22 = 5.01
hi range change to 3.54*1.4 = 4.96

4.96 is darned close to 5.01 and you get to keep the arguably stronger 3.54 pinion gear.

If I was doing it again, I'd do the t-case change....and leave the diff swap to a Toy / RoverTracks kit for later

KAA - The Other Keith

 

[tinker trek]

Thank all of you for your input on this..

I've gained a great deal of information on this.

Now my question going around it my head is if I should look
into having the hi range gear changed in the t-case or just go with
4.10's R&P..

My cost with R&P going through Great Basin Rovers would be $1600.
Thats parts & labor (both ends) Ready to drop back in.

I will have to check around to see what it would cost to just do the t-case.

 

[KevinNY]

Check with Justin at Lucky8, he has good prices on gears in stock.

 

[revor]

Remember gears are gears and diffs are diffs. Any local shop that does gears should be able to set up a Rover diff.

Look up Rob at MIT automotive solutions in evergreen, or check with JC's Rover and $x4 down off Hampton.

A good local resource is the Solihull Society (.org) if you haven't already been there.

 

[tinker trek]

Remember gears are gears and diffs are diffs. Any local shop that does gears should be able to set up a Rover diff.

Look up Rob at MIT automotive solutions in evergreen, or check with JC's Rover and $x4 down off Hampton.

A good local resource is the Solihull Society (.org) if you haven't already been there.

revor, I talked to JC's last week he wanted $2500. that price was if he did the job start to finish. Not if I just took him the carriers in, I didn't ask him if I could just do that. I'm sure he would work out a cheaper price for that?

After it's all said and done the price GB Rovers gave me would be hard to beat...Unless they are marking up the parts cost a great deal.. there labor cost is $200. per diff. The catch is the $160.total for shipping (not to bad considering the weight).
I also know a guy out in Aurora "Western drivetrain" but I would be surprised if he's any cheaper. Don't know till ya ask....

 

[Yorker]

you should probably look into the Equipe 4x4 gears- They were reasonable when I last checked- I can't find the retail price spreasheet I had at the moment otherwise I'd give you an idea.

[edit] I checked my old emails 354,20 was the price in jan 2007- who knows now with the exchange rate though- ask Justin or Roby or whoever the west coast Equipe dealer is.