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Which Manual Gearbox behind Gen 3

Posted: Thu Jul 27, 2006 3:39 pm
by discokid
Hi Guys

As many of you would know Im currently running a TF 727 behind my Gen 3 Defender for off road racing.

Im wanting to change to a manual so Ive got better gear selection. Im finding that Im doing a lot of the offroad racing courses in second only and it would be better to have a 2nd 3rd combination to get a bit more road speed.

My mate who races one has had a lot of manual conbinations including the old LT95 and LT 85. The main problem he has in blowing 3rd gear

Im thinking of getting a new R380 over an LT85 for a couple of reasons:

1) I can get a brand new R380 for cheaper that I can get a second hand reconditioned santana so it takes the fatigue factor out of the equation

2) Gear shift is heaps better in the R380

3) Parts for R380 are more common than Santana

Im just worried about strength

Ive been told that gear sizes and main shaft sizes are actually similiar

Help!

Posted: Thu Jul 27, 2006 3:50 pm
by HSV Rangie
R380. wont like the abuse though.

Michael.

Posted: Thu Jul 27, 2006 3:52 pm
by discokid
Wont like the abuse??

Will a santana be any different?

Posted: Thu Jul 27, 2006 4:14 pm
by 6.5 rangie
GQ patrol 5 speed, LRA does a kit to transcase and Marks will do the engine adapter.

Posted: Thu Jul 27, 2006 4:20 pm
by discokid
6.5 rangie

I thought of that

Only problem is the shifter will be a long way back ( like near the back of the cab ( its a defender ute) and I dont want to add more wieght to the car as that causes suspension hassles and other problems.

The nissan boxes have been raced here in WA as well and arent proving any more reliable that the LT 85. 3rd gear is still a problem every 3 or 4 races. In fact the guys that race patrols here are using the small box instead of the big one (they are cheaper)

I accept that Ill have to pull the box out regularly anyway to check it its just a question of which one.

Posted: Thu Jul 27, 2006 4:21 pm
by Loanrangie
I think you need to swap in a toploader box, no landy box will handle what you will be dishing out to it for long. Only other i can i think would be a T5 or a Tremec but these will be exxy.

Posted: Thu Jul 27, 2006 4:27 pm
by discokid
Im getting the feeling that I should be sticking with my Auto!

Im trying to avoid complications with more adaptors etc as well

Another question has anybody heard of or used a quaife kit apparently they do different gearsets for the R380 and I can change it dog change gears.

Im not sure how user freindly that will be

Posted: Thu Jul 27, 2006 4:49 pm
by HSV Rangie
auto is the go IMO.

plenty of upgrades for the ZF

or use the t700/le80

Michael.

Posted: Thu Jul 27, 2006 6:08 pm
by 6.5 rangie
Yeah full manual 4L80E

Posted: Thu Jul 27, 2006 7:20 pm
by justinC
JUST PUT IN THE ALLISON 4 spd auto AT545 AND BE DONE WITH IT.

700NM rating

25 litres oil capacity(!)

Good enough for a 6 cyl turbo isuzu 9 ton truck....

JC

Posted: Thu Jul 27, 2006 10:43 pm
by discokid
Has anybody seen or heard of these before.

http://www.rakeway.com/gearbox's.htm

Posted: Fri Jul 28, 2006 12:13 am
by stuee
I agree with 6.5 rangie. My preference would be a built 4l65e though as its a fair bit lighter. There are adaptors around you just have to find the right people. Thats the bonus of the 4l80e though is the readily available adaptors.

In standard guise max engine torque:
4l65e 380lbft or 515nm
4l80e 440lbft or 596nm

These can easily be upped to much larger figures, fully manualised, quicker shifts etc etc. For example a hsv 4l65e can take 400 lbft of torque.

How many $$ are you looking at for a gearbox like that discokid? Thats real handy the way it replaces the stock landrover gearbox.

Posted: Fri Jul 28, 2006 10:10 am
by discokid
thanks guys

I think most of these autos you refer to give you the extra gear but its an overdrive. I need 4 gears up to 1:1 unless I change my transfer case as well.

Im not sure how an overdrive in an auto works or whether it is just another gear and hence just as strong

Posted: Fri Jul 28, 2006 11:36 am
by HSV Rangie
How about a Quaife gear set for the R380 rover box.

http://www.quaife.co.uk/products/gearkits.asp

should solve most isues.
Michael.

Posted: Fri Jul 28, 2006 11:56 am
by discokid
They have some good stuff. Not sure about price though. Ive emailed them just to scare myself.

Some of the safari competiors in the UK are using their 6 speed sequential with 6th being 1:1 , Very nice you would be able to keep the revs up at all times with one of those

Check them out here

http://www.quaifeamerica.com/downloads/7-13.pdf

Posted: Fri Jul 28, 2006 12:34 pm
by HSV Rangie
was around 6K I thought


Michael.

Posted: Fri Jul 28, 2006 12:53 pm
by justinC
discokid wrote:thanks guys

I think most of these autos you refer to give you the extra gear but its an overdrive. I need 4 gears up to 1:1 unless I change my transfer case as well.

Im not sure how an overdrive in an auto works or whether it is just another gear and hence just as strong
Allison AT540 and 545 has 1:1 4th gear with no lockup clutch. Reverse is 5.2:1 !!!
JC

Posted: Mon Jul 31, 2006 11:34 pm
by discokid
Im giving up on the manual idea. Looks like to much work and money for 1 or 2 extra gears.

The main reason is the standard Gen 3 flywheel wont fit into an R380 or LT85. The Tremecs and Rakeway product are around around $5k+ without the cost of clutch, adapters, flyweheels new starter etc

Spent the $$$ getting to TF727 right so might as well run with it

Might try and get some more low down torque from the gen 3. Then I wont need the extra gear

which manual gearbox

Posted: Tue Aug 01, 2006 4:19 am
by 90pickup
got some very good news for you. the absolute master for the TFT (ATW in UK, his valve bodies are worlds apart from the Art-CARR ones!) builds now a overdrive for the 727, whixh only adds about 3 inch in lenght......should be worth the waiting!