tommobot Posted October 2, 2017 Share Posted October 2, 2017 My old transfer box cracked its case, so I got a replacement. My original I beleive was a 1.2 and the car topped out at 65/70mph~ I've got a second hand repalcement fitted, based on the serial no it was also a 1.2 or thereabouts. Fitted, it works fine but now topping out at 55mph~ It must have been changed on this unit in the past Seeing as I have the final ratio that I want, how much of a job is it to switch the two over? I've looked online, can't seem to find a guide for this, as it seems quite a common change? Can it be undertaken in situ, or must the transfer box be removed. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 2, 2017 Share Posted October 2, 2017 You need to take it out. Just follow the workshop manual. What engine is it that you have? Those are some pretty slow speeds. Have you checked your speed against a GPS? Your speedometer may be reading wrong. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 2, 2017 Share Posted October 2, 2017 That's a good point, unless you swapped the speedo drive gear between the boxes, it is likely your speedo is out! Could be a very simple fix then Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 2, 2017 Author Share Posted October 2, 2017 Mmmm valid point, it feels bloody slow, I'll get the GPS on it this evening. This is with a 200tdi, LT77 and LT230 transfer box on a 90 defender. Its on 33's but as said, seemed much quicker before. Perhaps its just placebo effect Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 2, 2017 Share Posted October 2, 2017 That seems very slow, it shouldn't struggle that much. Looking at your engine RPM Vs speed will tell you the (approximate) ratio you've got (REAL speed not speedo speed as your speedo / gear could be mis-matched). At the least I'd want to check the old gearset you're intending to swap in isn't damaged (did the case crack for a reason?), and that the boxes are indeed compatible types/builds - LT230R is not the same as LT230T for example. 1.2 boxes are cheap & plentiful so I'd be tempted to spend £50 on a replacement known good one and just fit that rather than faff about with gears. Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 2, 2017 Author Share Posted October 2, 2017 So I feel a bit of a cockspanner. Looks like I misread the serial no completely, I read this as a 28D, giving me a 1.2 but looks I may be way off, and can't see any refernce to that anywhere Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 2, 2017 Share Posted October 2, 2017 This says 1.667: They are somewhat sought after... For people that run bigger tyres. Quote Link to comment Share on other sites More sharing options...
Landrovernuts Posted October 2, 2017 Share Posted October 2, 2017 A 20D is a 1.667 ratio, I think, so if nobody has changed the gears may explain the max 55mph. Should pull well though! Toby Quote Link to comment Share on other sites More sharing options...
Landrovernuts Posted October 2, 2017 Share Posted October 2, 2017 Just seen the reply from Bowie so ignore me! Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 2, 2017 Author Share Posted October 2, 2017 carp. Maxed out at a gps verified 51mph. 😐 Quote Link to comment Share on other sites More sharing options...
Landrovernuts Posted October 2, 2017 Share Posted October 2, 2017 With your 33" tyres, 51mph equates to just over 2300RPM (using the Ashcroft ratio calculator) and you should be getting more than that! Toby Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 2, 2017 Share Posted October 2, 2017 I can get 80mph out of a 200tdi on 33's with a 1.4:1 t box and that's around 3800rpm ish. Granted it will take you longer to get there but with a 1.2 you should be able to see 80mph. Personally I wouldn't have a 1.2 on 33's but that's just me. Mike Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 2, 2017 Share Posted October 2, 2017 2 hours ago, tommobot said: carp. Maxed out at a gps verified 51mph. 😐 There is something wrong with your engine. With the 1.6, you should feel like a race car and run up to the rev limiter with no effort, which is up around 75 mph. Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 2, 2017 Author Share Posted October 2, 2017 I don't have a rev limiter, im only going by ear but at 50 it sounds like it's screaming. It may go 50+ but by sounded like it was nearly bouncing off the limiter already! On the old transfer box when doing 70 giving it is all, it sounded at less revs than it is now! Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 2, 2017 Share Posted October 2, 2017 You do have a rev limiter it's part of the injection pump from memory it's about 4250rpm. However if your t box is a 1.6 it would sound like it's screaming at 50mph especially if your used to a 1.2 t box. Mike Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 2, 2017 Share Posted October 2, 2017 The injection pump has a rev limiter built in. If you are at max revs at 50 mph in 5th gear, your clutch is slipping. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 2, 2017 Share Posted October 2, 2017 Or you are in low range, or in 3rd gear and think it is 5th. 1 Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 2, 2017 Author Share Posted October 2, 2017 Definitely not low range. I've checked that. It feels like 3rd!! 1st, 2nd,3rd,4th and 5th all work, abliet very closely matched. I'm contemplating changing to 5th at 35mph.. Tomorrow I'll stop being a pussy, and take some earplugs.. Quote Link to comment Share on other sites More sharing options...
tommobot Posted October 3, 2017 Author Share Posted October 3, 2017 Took some brave pills.. Got up to the dizzying heights of a GPS verified 61mph.. wow (speedo suggests 70) This is at about half throttle, but it sounds crazy revs, and personally I'm not a fan of revving the nuts off old diesel engines. Atleast I know I can go the same speed as lorrys, so no longer dangerously slow. It will do for a few months, I'll look at fitting a replacement in the new year probably.. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 3, 2017 Share Posted October 3, 2017 Gotta be good round town Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 3, 2017 Share Posted October 3, 2017 As someone said above, if you've got a 1.6 box you should have no trouble selling that on / px-ing it for a 1.4 or 1.2 plus some cash as the big boys like them. Are you 100% certain no-one's fitted lower ratio diffs to your truck at any point? Quote Link to comment Share on other sites More sharing options...
miketomcat Posted October 3, 2017 Share Posted October 3, 2017 Depending on where you are and timings I maybe interested in a 1.6 t box but I'm in no hurry. Mike Quote Link to comment Share on other sites More sharing options...
Ex Member Posted October 3, 2017 Share Posted October 3, 2017 You can't over rev or hurt the engine. The injection pump is governed at 3800 rpm and is safe to run as long as you want. I think you need someone to have a look at it for you or come for a drive. Either you have some other non stock gearing in there as Fridge suggests or you are not used to what they sound like. You probably need to hook up a tach. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 3, 2017 Share Posted October 3, 2017 Told you someone would want the 1.6 box! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 3, 2017 Share Posted October 3, 2017 Yup ^^^ Only thing rarer/more sought after is the 1.003, for early Rangies or low ratio axles users.... Quote Link to comment Share on other sites More sharing options...
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