straightshooter Posted July 6, 2011 Share Posted July 6, 2011 Hi I have just aquired a RRC bobtail 3.5 with an elly carb running 265 75 16 wheels it has also just had a 3.9 disco gearbox etc put in now had some different advice from people re diffs first that i should change the diffs i have on it to 3.9 diffs second I should change the diffs to series 3 diffs please tell what your opinions are out there Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 10 spline diffs,taken off a lightweight a couple of years ago 4.7.1 would these work????? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 3.9 and 3.5 diffs are exactly the same. Series ring gears are thinner than coiler-based axles, so you would be reducing the strength significantly. Manual or auto? Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 AUTO Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 Really need a better idea of why you want to change the ratios... But even so, you have a couple of options... Assuming you have an LT230 transfer box, it's most likely that it is a 1.2 ratio one, in which case swapping to a 1.4 ratio box would restore your on-road gearing, but leave your low-range unaffected (i.e. probabyl slightly too high). Get some high strength ring and pinions from the likes of Ashcroft or KAM and choose your ratio and drop them in, bit spendy though. What exactly is it you are trying to acheive...? The Disco auto box is no different to the Rangie one, ratio wise anyways. Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 Well firstly I am having a problem when driving the RR on the road it wont change to top gear normally I have to back off the power then she changes up then I can accelerate gently the engine sounds like its reving quite hi but not sure how high as my rev counter doesn't work as for what i would like to achieve well a normal ish drive whilst on the road good acceleration don't need a big top speed as this vehicle is mainly used for off road but there is a drive to and from and shooting also something that isn't going to cost the earth as I really don't have the funds at the moent as I have a few other projects on the go here is a picture Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 OK, as you don't sound too bothered by the ratio change off road (and why would you be, with an auto....), I'd stick with changing the transfer box for a 1.4 ratio item, you can pick them up for around £100 with a known history. Quote Link to comment Share on other sites More sharing options...
p76rangie Posted July 6, 2011 Share Posted July 6, 2011 Just adjust your kickdown cable so the thing changes gears at the right time. It sounds like you have it too tight at the moment and it needs to be slackened off a bit. Go to the auto store and buy a cheap tacho, it will at least tell you whether it is really over revving or not. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 Forgot to mention that... the kickdown cable adjustment is pretty crucial, HOWEVER, it will still not drive as it was designed to once you have larger tyres on it, getting very confused about when to change up/down, and lockup. The only way to restore the original driving 'feel' is by changing ratios. Quote Link to comment Share on other sites More sharing options...
p76rangie Posted July 6, 2011 Share Posted July 6, 2011 Tyres are borderline as to whether to change ratios or not. I would not bother. Tyres have nothing to do with it overrevving before changing gears. Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 ok will try the kickdown cable first if no good will look at transfer box i need enaugh power off road as i shoot on some very hilly land I used to own a freelander for my sins and it couldn't get up a lot of the hills I needed to get up also 1.4 transfer box ? what did they come out of? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 1.4 boxes are out of later(post 85 I think) 90/110s and Defenders Quote Link to comment Share on other sites More sharing options...
p76rangie Posted July 6, 2011 Share Posted July 6, 2011 ok will try the kickdown cable first if no good will look at transfer box i need enaugh power off road as i shoot on some very hilly land I used to own a freelander for my sins and it couldn't get up a lot of the hills I needed to get up also 1.4 transfer box ? what did they come out of? The different transfer case only changes high range, not low range. So if it is more power off road that you need it will not give it to you. You will need to change diff ratios instead. Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 as for the kickdown adjustment just been checking out my trusty haynes manual is this what they refer to as "kickdown band adjustment screw" located on the right hand side of the gearbox? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 6, 2011 Share Posted July 6, 2011 No, they are normally adjusted up by the throttle butterfly -there will be two cables attached, one is attached to your pedal, the other to the gearbox. 2 13mm nuts secures the one you want to adjust to the bracket. Haynes/other wokshop manuals will say to leave 1mm between the lead pip on the cable inner and the cable out, I find as cables get older 3mm seems about right, and mine revs to 5500 before changing up with my foot mashed to the floor Quote Link to comment Share on other sites More sharing options...
Pinkrover Posted July 6, 2011 Share Posted July 6, 2011 Hi Pete,Having done all the above mentioned, I can say that an automatic V8 will not like tyres over 32" on the road, for all the reasons above and adjusting the kick down cable will not alter this.I have fitted 1.44 tranfer boxes in the past and they help on road, in my opinion they are not quite enough on their own and but they don't change the low ratio , so off road you lose some tractability and control. I have fitted ashcrofts 4.11 diffs to my present soft dash with 33" tyre and it drive as though it has std tyres on and is by far the best of the 5 RRC I have had. A plus point of the ashcroft diffs is the front one has the gears cut in the correct direction. so IMHO there is only one way to go or lots of compromises.....good luck.Les Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 6, 2011 Author Share Posted July 6, 2011 my problem is not kick down it just doesn't change into top gear without me backing off the power a touch first Quote Link to comment Share on other sites More sharing options...
p76rangie Posted July 7, 2011 Share Posted July 7, 2011 my problem is not kick down it just doesn't change into top gear without me backing off the power a touch first The kickdown cable controls both changing up and changing down. You backing off the power releases the cable and allows it to change up. Lengthening the adjustment will have the same impact and allows it to change up earlier. Quote Link to comment Share on other sites More sharing options...
straightshooter Posted July 7, 2011 Author Share Posted July 7, 2011 cool will give it a go and let you know how it goes Quote Link to comment Share on other sites More sharing options...
hutchey Posted August 22, 2011 Share Posted August 22, 2011 Hi Pete,Having done all the above mentioned, I can say that an automatic V8 will not like tyres over 32" on the road, for all the reasons above and adjusting the kick down cable will not alter this.I have fitted 1.44 tranfer boxes in the past and they help on road, in my opinion they are not quite enough on their own and but they don't change the low ratio , so off road you lose some tractability and control. I have fitted ashcrofts 4.11 diffs to my present soft dash with 33" tyre and it drive as though it has std tyres on and is by far the best of the 5 RRC I have had. A plus point of the ashcroft diffs is the front one has the gears cut in the correct direction. so IMHO there is only one way to go or lots of compromises.....good luck.Les Glad i read this as i have an rrc 3.5 v8 with 37 inch on the road. was looking at the transfer box versus diff ring & pinion options. so assuming i have the 1.2 transfer box (make and model unknown)am i better looking for the diffs for road use? thanks Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 25, 2011 Share Posted August 25, 2011 Up to you really, a 1.6 t-case will drop the ratio nicely for you, but so will different R&P, and include dropping the low range at the same time. I agree I would probably go with diffs next time, but I wanted to kill a few birds with one stone, X-brake, ratio change and guaranteed diff lock -it works well for me on and off road. Give ashcrofts a ring and spend £500+ or swap out your t-case for second hand one £100, up to you Quote Link to comment Share on other sites More sharing options...
straightshooter Posted February 6, 2012 Author Share Posted February 6, 2012 well guys have adjusted the kickdown cable at last and eureka thanks guys Quote Link to comment Share on other sites More sharing options...
straightshooter Posted February 6, 2012 Author Share Posted February 6, 2012 now to find a 1.4 ration box Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 6, 2012 Share Posted February 6, 2012 Good job, took you a while though Quote Link to comment Share on other sites More sharing options...
straightshooter Posted March 10, 2012 Author Share Posted March 10, 2012 well adjusted the kickdown cable and it's a lot better so thanks guys Quote Link to comment Share on other sites More sharing options...
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