bignum Posted October 9, 2013 Share Posted October 9, 2013 I have a large casing manual diff atm and i`m looking to swap for an auto tt diff to change the ratio, my question is.. Will i need the rear section of a auto propshaft and will i need to swap the left driveshaft. Cheers. Quote Link to comment Share on other sites More sharing options...
SPG Posted October 9, 2013 Share Posted October 9, 2013 Left driveshaft needs changing, the prop will also need changing Quote Link to comment Share on other sites More sharing options...
bignum Posted October 9, 2013 Author Share Posted October 9, 2013 Left driveshaft needs changing, the prop will also need changing Roger that, cheers. Quote Link to comment Share on other sites More sharing options...
little num Posted October 9, 2013 Share Posted October 9, 2013 only if you swap to a small casing diff, if you get a uk spec auto diff that's a large casing so nothing will need swapping, or maybe the flange for the prop but im sure all the large diffs have the same flange. Quote Link to comment Share on other sites More sharing options...
Pig Posted October 9, 2013 Share Posted October 9, 2013 only if you swap to a small casing diff, if you get a uk spec auto diff that's a large casing so nothing will need swapping, or maybe the flange for the prop but im sure all the large diffs have the same flange. Correct. Mine was a straight forward swap, nothing needed changing.... Bar the diff Quote Link to comment Share on other sites More sharing options...
SPG Posted October 9, 2013 Share Posted October 9, 2013 Apologies I was assuming an upgrade to a larger cased diff, where my statement would have been correct. Quote Link to comment Share on other sites More sharing options...
Jos Posted October 9, 2013 Share Posted October 9, 2013 (edited) I believe even with the larger cased diff to small cased diff swap the driveshaft doesn't need changing... all the left driveshafts are the same lenght (as are all the right ones). http://www.mkivsupra.net/vbb/showthread.php?267375-big-diff-driveshaft-measurements-please&highlight=driveshaft+measurements Edited October 9, 2013 by Jos (see edit history) Quote Link to comment Share on other sites More sharing options...
bignum Posted October 9, 2013 Author Share Posted October 9, 2013 Ah right cool then, on the lookout for 1 then. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted October 9, 2013 Share Posted October 9, 2013 Probably not an option, but if you wanted to come to Lincoln and pick it up, Ive got a non LSD auto diff you can have for nowt, good for parts maybe? Quote Link to comment Share on other sites More sharing options...
Mario Posted October 9, 2013 Share Posted October 9, 2013 (edited) IMO when changing from an large case to an small case diff, you'll need to change the rear left driveshaft as well as the propshaft. Have a look here for reference and pictures.http://mkiv.com/techarticles/auto_to_6spd_swap/differential/index.html ^^above link shows difference in length of the rear left driveshaft, it's an short description from auto to manual but shows whats needed in the process when you decide to go small case (3.7 final drive). Best of luck with the swap. Edited October 10, 2013 by Mario (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 10, 2013 Share Posted October 10, 2013 (edited) How bonkers that Toyota have made it so complicated ! On the Mk3 Supras even though they may vary in shape ALL the diffs have the same fitting dimensions, whether they are from N/A or Turbo cars with the W58, R154 or Auto box, with or without LSD . . so they can be easily swapped from ANY model to change your gearing. Edited October 10, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
dandan Posted October 10, 2013 Share Posted October 10, 2013 I believe even with the larger cased diff to small cased diff swap the driveshaft doesn't need changing... all the left driveshafts are the same lenght (as are all the right ones). http://www.mkivsupra.net/vbb/showthread.php?267375-big-diff-driveshaft-measurements-please&highlight=driveshaft+measurements No. One of the shafts is a different length - 5mm if I remember correctly. Some people have bodged it without changing through but I'm not sure if that increases the chance of damaging the diff itself of the shaft seal on the one side at full bump or rebound. Quote Link to comment Share on other sites More sharing options...
Jos Posted October 10, 2013 Share Posted October 10, 2013 Lol, everybody says you need to change the left driveshafts, but I have compared big diff and small diff shafts and there is no difference in length.... I know the manual says there should be 5 mm difference but there isn't, I bought a couple of sets to compare them. Quote Link to comment Share on other sites More sharing options...
SPG Posted October 10, 2013 Share Posted October 10, 2013 My comment was made as I changed from a small cased A02b to a large cased J-spec Manual LSD, and on comparing the two left hand D/shafts I found they were different lengths, not massively different but 5mm was about right. Quote Link to comment Share on other sites More sharing options...
Jos Posted October 10, 2013 Share Posted October 10, 2013 In uncompressed state there is a lot of difference in driveshaft length, it literally depends on how you hold the shaft, however compressed I found no difference? Quote Link to comment Share on other sites More sharing options...
dandan Posted October 10, 2013 Share Posted October 10, 2013 (edited) Compressed length was approx 5mm different on the near side shaft I used from a pre-facelift import (with a large diff) compared to my facelift small diff shaft. I can't say it any simpler. Did you remove the shafts from the large diff cars yourself or buy them as plain shafts from someone. Maybe you got sold something different? Simon, you might be fine with the small diff shaft. I've never done it so can't say first hand if the length difference affects anything. Edited October 10, 2013 by dandan (see edit history) Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted October 10, 2013 Share Posted October 10, 2013 There is definitely a small difference, 5mm as Dan says. Verified by myself and DaveP, using two different(Small and Large Case) driveshafts. -Longer LH Driveshaft: Came from my 1994 (Originally Auto) N/A with small case diff. -Smaller LH Driveshaft: Came from a factory TT6 with factory fitted large case diff. I removed both the driveshafts myself from both cars. Quote Link to comment Share on other sites More sharing options...
bignum Posted October 10, 2013 Author Share Posted October 10, 2013 Cheers for the info guys, but tbh i`m not getting hung up on the driveshaft issue its more the prop i`m thinking about. Quote Link to comment Share on other sites More sharing options...
Jos Posted October 10, 2013 Share Posted October 10, 2013 Compressed length was approx 5mm different on the near side shaft I used from a pre-facelift import (with a large diff) compared to my facelift small diff shaft. I can't say it any simpler. Did you remove the shafts from the large diff cars yourself or buy them as plain shafts from someone. Maybe you got sold something different? Simon, you might be fine with the small diff shaft. I've never done it so can't say first hand if the length difference affects anything. In that case my appologies for wrong info, and I'm glad somebody else finally made the effort of measuring them, could you share your measured lengths, so I can compare them to mine and for future reference. I bought the driveshafts from very respected members on here, so no doubt they were big diff ones. Only explanation I got is my original shaft was incorrect?, so compressed measurements would be helpfull please. Quote Link to comment Share on other sites More sharing options...
Mario Posted October 10, 2013 Share Posted October 10, 2013 The reason for the left drive shaft being 6mm shorter is due to the big diff's left side is a bit longer then the small case diff. Thats why Toyota made the left side drive shafts shorter for the big cased diff. Quote Link to comment Share on other sites More sharing options...
dandan Posted October 10, 2013 Share Posted October 10, 2013 (edited) From memory the props are about 15 or maybe 20mm different in length. I have some photos on my laptop from when I did the swap so I'll take a look... Edited October 10, 2013 by dandan (see edit history) Quote Link to comment Share on other sites More sharing options...
Jos Posted October 11, 2013 Share Posted October 11, 2013 (edited) Prop is indeed 20 mm shorter. And I'm still curious what the exact compressed lengths are, I know the diff is bigger, that's why I posted the thread I linked previously Edited October 11, 2013 by Jos (see edit history) Quote Link to comment Share on other sites More sharing options...
JamieP Posted July 7, 2014 Share Posted July 7, 2014 Anyone know the compressed length the left shaft should be for a big case diff? Quote Link to comment Share on other sites More sharing options...
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