harley-jm Posted August 8, 2008 Share Posted August 8, 2008 Ive gota an auto NA with an open diff with a manual & v8 conversion and I now need to change the rear end to cope. Searching previous threads I know rearends come in large and small housings and that apparently all the cars other than the early 6-speeds have the smaller housing and that there are different diff ratios NA/6sp/Auto. I've seen lots of threads stating that the NA diff is very weak and from what I have seen the TT one is very durable. I need to decide whether to swap my entire NA auto housing for one with an LSD in it already or use an aftermarket LSD like the TRD one in my existing housing. The car is ultimately going to have around 600bhp. Do people think the stock Toyota LSD will cope? Also how much better is the performance of the aftermarket diffs? I will use the car on the road, some dragging just for fun and some track days. The real question I had in relation to just getting an aftermarket diff centre is whether the NA crown wheel and pinion would still be a weak link? Is the NA stuff weaker than the TT version even if I uprate the actual diff itself? Are the NA half shafts the same? Also I assume a TT complete housing would bolt up to the NA half shafts and rear prop? Can anyone confirm? All info much appreciated! Cheers Paul Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 8, 2008 Share Posted August 8, 2008 (edited) Depends how hard you drive it but with the torque of a V8 and 600bhp i think even a 6 speed lsd will struggle, ive broke two 6 speed diffs on a 600bhp supra. Drive shafts on facelift cars and prefacelift are different. IIRC the rear props are only different on auto and manuals na or tt makes no odds. Edited August 8, 2008 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 8, 2008 Share Posted August 8, 2008 I'd try and find an early TT dif, the CWP's are bigger, with more tooth area and are are stronger. Couple it with the correct TRD LSD centre section nd it's as strong as you can get using a stock casing. After that you are into fabrication and a lot of expnse grafting in something like a merc SL65 AMG diff or a Bentley Continetal GT one, assuming the ratios available aren't daft. These monsters with around 700 ft / lbs of toque in 2 ton plus of metal should have beefy diffs... Quote Link to comment Share on other sites More sharing options...
Homer Posted August 8, 2008 Share Posted August 8, 2008 Just to add to Jamie's reply. Ignore whether it's facelift or not and look at the diff itself. The NA and auto LSD diffs can use the same prop and driveshafts. The NA diff is a LOT weaker than the auto LSD, however the LSD also comes in two crownwheel sizes (check A and B on the VIN), the B (larger) crownwheel is the stronger of the two by quite some margin. Only the 6spd LSD uses a different housing and therefore needs a shorter prop and unequal length driveshafts. They are incredibly strong. You also need to look at the drive ratio as this will have a major impact on the final drive ratio. 01 is used in the NA diff and has a short ratio, 02 in the manual and I think 03 in the auto's/UK cars for a tall gearing. Which V8 is going in? What RPM is the peak power band in? Quote Link to comment Share on other sites More sharing options...
harley-jm Posted August 9, 2008 Author Share Posted August 9, 2008 thanks for the responses. Between the three of you it sounds like the simplest initial option is to swap the entire housing for an early auto TT LSD which should bolt right up. By chance I think I can locate one as Jezz just took one off an auto TT supra I had him convert to manual. Just need to have him track it down.... When I get the v8 car back from the bodyshop I need to check the actual trans code to confirm the ratios in the box but I think they are closer to the auto ratios (i.e. relatively high numerically) than the manual which would mean the auto CWP/diff would match nicely (3.7?) as opposed to the manual one (nearer 3-3.2?). The NA diff I have at the moment (4:1) is a little bit high. I suppose checking the g-box ratios is the first step. May be worth fitting the TRD diff anyway (new bearings seals etc) rather than mess around with an old unit which is more likely to let me down later. Either way it doesnt address the issue of the strength of the CWP. Im not going crazy with power so hope the standard toyota one will do. Interesting snippet of info Chris re: different sizes and strengths. Ive seen guys running low 10s on slicks with what I assume is the standard CWP so I assume it will do for now - dont fancy fitting a ford 9" rear end! Jamie when you say youve broken two diffs is that the diff unit itself or the CWP/losing teeth? I know it can be a horrible experience - on other cars Ive had pieces of diff blow holes in the housing and leave a trail of parts down the road. I know you like to "enjoy" your cars though... was at Turbofit once when you were "road-testing" some mods they had just done and you disappeared up the road sideways in a cloud of smoke leaving two black lines..... Cheers Paul Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 9, 2008 Share Posted August 9, 2008 (edited) The auto TT diff has lower gearing to the manual one by a fair amount, the diff have split into pieces every time, and ive broke a lot more than two, 2 manual diffs lasted the longest, auto diffs never lasted long. You should have come say hi;) I may have a pic of one of the broken diffs, ill have a look. Edited August 9, 2008 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 9, 2008 Share Posted August 9, 2008 These are the only ones i could find. Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 9, 2008 Share Posted August 9, 2008 This time the donut came away and the prop went through the floor, i think that was an auto diff that time. Quote Link to comment Share on other sites More sharing options...
harley-jm Posted August 10, 2008 Author Share Posted August 10, 2008 Thanks Jamie I cant open these remotely but I'm interested to see your scrap metal once I get back home cheers Paul Quote Link to comment Share on other sites More sharing options...
harley-jm Posted August 11, 2008 Author Share Posted August 11, 2008 Jamie damn! you have been having fun.... looks like you broke the whole nose off the diff? Just as well you broke that end not further forward on the prop or you could have pole volted yourself down the road or put the prop through the floor and up somewhere painful. You need a driveshaft safety loop! Have you found a rear end solution yet or do you just swap in another one since stock ones come up regularly? Cheers P Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 11, 2008 Share Posted August 11, 2008 Ive not got that car now, the prop did make a hole in the floor a couple of times. Think it must be the drifting that kills them, gonna try and look After this car, no rolling burnouts or big drifts. Ive got one 6 speed diff put aside just incase;) Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 11, 2008 Share Posted August 11, 2008 One of the floor taking a beating. Quote Link to comment Share on other sites More sharing options...
SteveR Posted August 11, 2008 Share Posted August 11, 2008 Quote Link to comment Share on other sites More sharing options...
Trig Posted August 11, 2008 Share Posted August 11, 2008 jesus! you dont half know how to break them Jamie! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 11, 2008 Share Posted August 11, 2008 Diff broken, ashtray full, he just buys a new car, no worries Quote Link to comment Share on other sites More sharing options...
JamieP Posted August 11, 2008 Share Posted August 11, 2008 Nah, cant afford to smoke:D Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 11, 2008 Share Posted August 11, 2008 Yeah, right! Only smoke tyre rubber do you? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.