jlo1986 Posted April 27, 2007 Share Posted April 27, 2007 Hi guys,My diff is on it's way out and so I’m looking at either getting it restored (which costs £££!) or buying a decent used one. There's one on eBay at the moment which has a 4.11:1 ratio and is supposedly in good condition. Now as i have a late 1500 I guess that it's not the same ratio as mine (3.63:1 I believe) but could I still use it and if so would it be a straight replacement and what other effects could it have.Cheers, Jamie Link to comment Share on other sites More sharing options...
CharlieB Posted April 27, 2007 Share Posted April 27, 2007 I wouldn't recommend it for a 1500, although it would give you better acceleration, your engine would be reving much faster for any given speed, not good on the motorway & your speedo would read too fast.Also I think standard 4.11 diffs might have weaker output shafts.A 3.89 is a good choice if you have overdrive. Link to comment Share on other sites More sharing options...
Tim Bancroft Posted April 27, 2007 Share Posted April 27, 2007 In light of the ability of a 1500 engine to hate revs, stick with the 3.63:1 jobbie. Link to comment Share on other sites More sharing options...
Deleted User Posted April 27, 2007 Share Posted April 27, 2007 post removed on request of author Link to comment Share on other sites More sharing options...
AndreGT6 Posted April 27, 2007 Share Posted April 27, 2007 No kidding, but I do love my 411 :) Once I'm all setup I want to 1 dyno the GT6 then 2 get a 0-60 test :)A. Link to comment Share on other sites More sharing options...
GT6Steve Posted April 27, 2007 Share Posted April 27, 2007 I'm with Rotoflex. The GT6 thrives on the 3.63 and they are rare. I've been known to buy a complete TR7 (for pennies, mind you) just to get the diff and three rail trans. Sadly those days are gone. Link to comment Share on other sites More sharing options...
Tim Bancroft Posted April 28, 2007 Share Posted April 28, 2007 For good road use in a GT6 a 3.63 is the one, with late J type overdrive and 175/70 rubber- its what 21/22 mph/1000 revs- marvellous.Same for a 1500 Spit- use the torque. Link to comment Share on other sites More sharing options...
Deleted User Posted April 28, 2007 Share Posted April 28, 2007 Are you serious? 3.63 ratios are rare now?Actually I thought the final drive ratio with 3.63 and 27/ 28% overdrive would come out to about 22.5/23 mph/1000.This gives 100mph at 4350rpm, 120 at 5200, 135 at 5900 which seems to be spot on for a 2L modified car. (oh and 70mph at 3000!) Link to comment Share on other sites More sharing options...
Tim Bancroft Posted April 28, 2007 Share Posted April 28, 2007 0.5mph/1000-apols! Link to comment Share on other sites More sharing options...
Clive Posted April 28, 2007 Share Posted April 28, 2007 I think in the US they are rare. Loads in the UK but a bit heavy for shipping? They are a good ratio for my 2.5 vitesse too. Seem to last a bit better than the 3.27's.And cheaper to buy, my used 3.27's are no good for rebuild :-/Clive Link to comment Share on other sites More sharing options...
Deleted User Posted April 28, 2007 Share Posted April 28, 2007 3.27s are a bit of a problem from the very beginningMost ppl don't realise there are almost no common parts between the other ratios, and early ones can be a problem to repair unless you can find a good s/h carrier.The diff carrier is unique to that model, as because of the (huge) size of the pinion the carrier had to be machined at triumph, thinned down and offset to squeeze it all in.Then the crownwheel bolts all had to be shortened with small heads and spring washers removed.Finally the crownwheel is made quite thin.So there are several weaknesses, -The pinion has large long teeth which are easier to rip off.The carrier is very prone to hair line cracks until the POST 1975 reinforced model was made as it has no stress relieving in the rough cast surface.The crownwheel bolts have to be locktited in, and sometimes snap off when tightening them up, which is not funny to remove as the metal to be extracted is "v" rated.The bearings on very early models are strong (15245), but the carrier is even weaker on Mk1GT6.The intermediate bearing 67048 is overloaded for this application, wears fast and comes under mesh stress (distortion of the case and bearing under load) when hammered with a fast 2.5L engine.The Late bearing 68149 is up to it, but the late carrier can't be used in the early axles...and is rather rare to find.For a 2.5L the 3.27 is THE ratio to use. Link to comment Share on other sites More sharing options...
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