Supra TRD install questions
10-27-14, 05:29 PM
#1
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Supra TRD install questions
Hello all
So I've been sitting on a TRD differential for over a year out of a fear of the installation. My main question is about the backlash. I've research for many hours having difficulty find an solid answer.
I understand that shims will adjust the backlash but I found a thread of the supra forum stating that non are needed and it's really just a bolt on.
If you guys can help me with the actual shim part that would be awesome.
A little history, I have a 1995 factory 5 speed sc300
So I've been sitting on a TRD differential for over a year out of a fear of the installation. My main question is about the backlash. I've research for many hours having difficulty find an solid answer.
I understand that shims will adjust the backlash but I found a thread of the supra forum stating that non are needed and it's really just a bolt on.
If you guys can help me with the actual shim part that would be awesome.
A little history, I have a 1995 factory 5 speed sc300
10-27-14, 08:54 PM
#2
The thread you found on SF would not have been accurate if the only information was that the diff just bolts in. There absolutely are measurements required and an inspection of the resulting ring and pinion mesh patterns using Prussian Blue. If someone did all their measurements correctly and found that they lucked out and didn't need shims, that is a RARE thing to happen. No diff will be exactly the same as another where those shims are concerned and that is why Toyota stocks different thicknesses. Even the rear pinion alignment can be affected by not torquing the companion flange within factory specs.
A differential is not overly complicated but it does require following the manual tolerances and being very meticulous. Shims are only part of the process.
If you just go and bolt in your TRD LSD and don't measure and order whatever thickness brings things back into spec according to the factory service manual (SC or MKIV) then you can cause damage to the internal components in not too many miles.
I had an LSD rear end custom rebuilt for my SC 5-speed. I trusted it to a shop with someone experienced in driveline and differential work. If it's not a procedure you are familiar with that is what I would recommend for you as well. It can be learned and I don't want to dissuade you from doing so if learning about the process of the rebuild is a worthwhile project to you but be advised you need to really know what you're doing and get it right the first time. Getting a shop to do it shouldn't cost too much with new seals and parts-- Mine was around $350 labor IIRC.
A differential is not overly complicated but it does require following the manual tolerances and being very meticulous. Shims are only part of the process.
If you just go and bolt in your TRD LSD and don't measure and order whatever thickness brings things back into spec according to the factory service manual (SC or MKIV) then you can cause damage to the internal components in not too many miles.
I had an LSD rear end custom rebuilt for my SC 5-speed. I trusted it to a shop with someone experienced in driveline and differential work. If it's not a procedure you are familiar with that is what I would recommend for you as well. It can be learned and I don't want to dissuade you from doing so if learning about the process of the rebuild is a worthwhile project to you but be advised you need to really know what you're doing and get it right the first time. Getting a shop to do it shouldn't cost too much with new seals and parts-- Mine was around $350 labor IIRC.
Last edited by KahnBB6; 10-27-14 at 08:59 PM.
10-28-14, 12:08 PM
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350 labor is a good price but what I'm finding is 3 trusted shops I called want 800 in labor which is bizarre ha.
Thanks for the clarification so everything has to be remeasured even when using the factory ring gear correct?
Thanks for the clarification so everything has to be remeasured even when using the factory ring gear correct?
10-28-14, 07:22 PM
#4
$350 labor was a good deal and the guy did know what he was doing. This was through Driftmotion. It could have been $400 but no more than that. My regular mechanic said he usually sees differential rebuilds ball parked in the $800-$900 range and I chalk this up to farming out to another shop with a general price structure for that kind of work.
Bottom line is the person doing it needs to know what they are doing and also you need to shop around for a reasonable price on top of that. Three shops in a row giving the same answer isn't fun. Maybe my experience is a rare exception...
Basically yes, you need to take precise measurements and weigh those against the factory tolerances laid out in the Toyota service manual. If your measurements suggest you will need shim thickness xxxx to bring the left side into spec and shim thickness yyyy to bring the right side into spec then you DO need to order those shims from Toyota and install them. Again, this is also where using Prussian Blue for temporary marking comes into play. The manual shows what visual examples of a correct gear mesh/wear pattern look like and what incorrect patterns look like.
$800+ is a lot but I have also heard of these labor estimates. Keep looking.
Also, if you do have to pay anything close to those figures, be sure of what gearing you want so as not to have to cover the same ground twice. What is your goal for the car? Stay NA or future turbo build? 4.083 was the stock ratio for 1JZ-GTE 5-speed combinations in the Soarer but most people like going with a 3.92 (SC400 diff) or 3.769 (Supra TT Auto diff ratio) for turbocharging.
If you're not going to turbocharge the car any time soon (because those lower gears are ideal for turbo and terrible for NA) stay with your stock 4.083:1 ratio or pick up a 4.272:1 ratio.
Bottom line is the person doing it needs to know what they are doing and also you need to shop around for a reasonable price on top of that. Three shops in a row giving the same answer isn't fun. Maybe my experience is a rare exception...
Basically yes, you need to take precise measurements and weigh those against the factory tolerances laid out in the Toyota service manual. If your measurements suggest you will need shim thickness xxxx to bring the left side into spec and shim thickness yyyy to bring the right side into spec then you DO need to order those shims from Toyota and install them. Again, this is also where using Prussian Blue for temporary marking comes into play. The manual shows what visual examples of a correct gear mesh/wear pattern look like and what incorrect patterns look like.
$800+ is a lot but I have also heard of these labor estimates. Keep looking.
Also, if you do have to pay anything close to those figures, be sure of what gearing you want so as not to have to cover the same ground twice. What is your goal for the car? Stay NA or future turbo build? 4.083 was the stock ratio for 1JZ-GTE 5-speed combinations in the Soarer but most people like going with a 3.92 (SC400 diff) or 3.769 (Supra TT Auto diff ratio) for turbocharging.
If you're not going to turbocharge the car any time soon (because those lower gears are ideal for turbo and terrible for NA) stay with your stock 4.083:1 ratio or pick up a 4.272:1 ratio.
Last edited by KahnBB6; 10-28-14 at 07:29 PM.
10-28-14, 08:43 PM
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Ya I'm really not wanting to pay that and I don't have full confidence in order to do this job.
I'm going na-t in the near future as I have most of my parts but I was planning on keeping 4.08 but I'm open to the idea of another ratio have you had any experience with other ratios?
I'm going na-t in the near future as I have most of my parts but I was planning on keeping 4.08 but I'm open to the idea of another ratio have you had any experience with other ratios?
10-29-14, 12:46 AM
#7
For an NA-T you can use the 4.08 but it was paired with the 5-speed 1JZ in this car to compensate for the .5L less displacement and create a sportier drive (at factory boost generating 280hp or so). Some people use it and some don't.
I do not have direct personal experience yet (still collecting parts for my GTE swap) but most people recommended to me either the 3.769:1 Supra TT Auto ratio as the most ideal and a much easier to find 3.916:1 (3.92) as the next best thing. These are both good when paired with a 5-speed manual transmission.
You can also get a GS400 3.26:1 rear end but it is so low it's going to kill your low end until boost kicks in. It's a popular ratio when swapping in a V160 6-speed because it is similar to the 3.133:1 ratio big diff it came with in the US Supra TT.
The 3.769 is the best of all worlds for a 5-speed application but it is getting harder to find now.
I do not have direct personal experience yet (still collecting parts for my GTE swap) but most people recommended to me either the 3.769:1 Supra TT Auto ratio as the most ideal and a much easier to find 3.916:1 (3.92) as the next best thing. These are both good when paired with a 5-speed manual transmission.
You can also get a GS400 3.26:1 rear end but it is so low it's going to kill your low end until boost kicks in. It's a popular ratio when swapping in a V160 6-speed because it is similar to the 3.133:1 ratio big diff it came with in the US Supra TT.
The 3.769 is the best of all worlds for a 5-speed application but it is getting harder to find now.
Last edited by KahnBB6; 10-29-14 at 12:49 AM.
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10-29-14, 03:59 PM
#9
As long as you don't touch gears, you can usually get away with dropping a non-LSD for an LSD. As soon as you touch the ring and pinion expect that you'll have to buy shims and redo the pinion depth and backlash.
I didn't know you could use prussian blue! I always used white lithium grease.
I didn't know you could use prussian blue! I always used white lithium grease.
10-29-14, 10:02 PM
#11
Intimazy, all the guides (including the Toyota service manual) I read that served to scare me into using a professional diff rebuilder mentioned Prussian Blue but that's a great alternative. I just learned something too 
^^ To what was just mentioned, kayrohit12, even if you were to remove the stock open diff, remove the ring gear, heat it up and get it onto your new LSD and install it into the pumpkin you are still changing the precise area where that gear meshed with the pinion which means you have to measure for proper tolerance compliance and apply the correct shims as necessary.
I'm west but not in Washington, sorry. Beautiful state btw.
^^ To what was just mentioned, kayrohit12, even if you were to remove the stock open diff, remove the ring gear, heat it up and get it onto your new LSD and install it into the pumpkin you are still changing the precise area where that gear meshed with the pinion which means you have to measure for proper tolerance compliance and apply the correct shims as necessary.
I'm west but not in Washington, sorry. Beautiful state btw.
10-30-14, 05:09 AM
#12
I get the fears. It's a whole different set of tools than most garage mechanics are familiar with.
Generally, as long as you don't replace the ring and pinion you won't have to touch backlash or pinion depth. As soon as you replace either or both, you WILL need to reshim. It even applies for the pinion crush sleeve replacement.
Picking up a feeler and magnetic base is cheap. Tube of white lithium as well.
When I did the Kaaz into the 4.08 and then when I put the same Kaaz into the 3.26 out of an sc430 I didn't need to reshim.
Generally, as long as you don't replace the ring and pinion you won't have to touch backlash or pinion depth. As soon as you replace either or both, you WILL need to reshim. It even applies for the pinion crush sleeve replacement.
Picking up a feeler and magnetic base is cheap. Tube of white lithium as well.
When I did the Kaaz into the 4.08 and then when I put the same Kaaz into the 3.26 out of an sc430 I didn't need to reshim.
10-30-14, 03:26 PM
#13
^^ I can do a lot of engine work but so far nothing that requires shimming and tolerances. Lot of respect for getting into that yourself.
If it's not too far off topic, how have you liked the 3.26 gearing with your R154? I've read of a few people without 6-speeds using it but it seemed like it would only work with a very high boost engine.
If it's not too far off topic, how have you liked the 3.26 gearing with your R154? I've read of a few people without 6-speeds using it but it seemed like it would only work with a very high boost engine.
Last edited by KahnBB6; 11-02-14 at 01:35 AM.
11-01-14, 07:01 AM
#14
It's not ideal in slow driving and makes hill starts more difficult but with a stock weight flywheel it's very tolerable.
On the highway? It's awesome. I practically idle at highway speeds in 5th gear. Very good on gas and really I'm just a downshift away from boost anyway.
I don't regret it at all so far.
On the highway? It's awesome. I practically idle at highway speeds in 5th gear. Very good on gas and really I'm just a downshift away from boost anyway.
I don't regret it at all so far.
11-01-14, 12:27 PM
#15
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How did you like the 408 there is a 400 at the local junkyard I'm thinking of getting the differential so I need to decide if I wanna keep 408 or not