3.13:1 What Lexus is it out of❓ I know the RCF comes with a 3:13 axle ratio - That one is too small for an LC

Lou

 

Just to bring back this thread. After having made this change seven months ago, I can report there is absolutely no downside. The Lexus 10-speed gear ratios handle the change with ease. More jump off the line, and firmer downshifting when slowing. In tenth gear. When cruising at 80, RPMs are still just a bit below 2K, so the engine is loafing. Lexus should have made this rear end standard on the LC. I should have made the change earlier

Lou

 

Lou congratulations on your successful outcome. 80 MPH at less than 2,000 RPM is impressive!
What did you do with the original LC 500 rear transaxle and differential? I imagine that Lexus was attempting to get as much fuel mileage as possible with the higher ratio standard (2.93.1?) transaxle.

Any fuel mileage or speedometer accuracy differences?

 

^^^^I tried to sell it on eBay. No Luck

According to OBD link, the Lexus speedometer reading was always inaccurate - reading too low. As far as mileage change - I don't see any

Lou

 

Hey, folks, it's Michael from the front page editorial team. Dropping into this thread because I've followed it for a while now -- we even turned it into an article -- and had an interesting conversation last week while on a press trip with Toyota.

I had dinner with a Toyota exec, who is also a proud LC owner (a coupe with an aftermarket carbon fiber hood/fenders and 22" aftermarket wheels). It seems he's aware of 500h diff-swap mod (although I'm not sure if he's read this specific thread), and had a point of caution I thought I'd share.

His warning was that -- without transmission tuning -- the taller gear ratio is going to cause drag on the transmission when you're cruising or lugging around. Not on acceleration or when power is being applied, he said, but more when coasting or very little throttle inputs. His take, after presumably talking to folks inside the company, is that this mod -- again without a trans tune -- COULD lead to premature wear and tear on the transmission.

I don't mean to rain on anyone's parade -- nor do I have any more to share -- but I just wanted to put this out there as an extra bit of information folks should consider before doing this modification. And, for those who have already done it, it might be worth doing more frequent transmission inspections or services. And hopefully someday Lexus trans tuning will be more accessible (assuming I understood correctly that it is currently unavail).

Cheers.

 

@MPalmer
i’m sure people who are seriously considering the swap appreciate the additional information and feedback to factor into their decision making process. With rare exceptions there are always two sides (Pros and Cons) to a story.

 

I take the negative post from MPalmer with a grain of salt IMHO, I don't believe any of it Googling it - provides this reply:



This modification has been a classic hot rodder's "go to" for many years. The only downsides I am aware of are a reduction in top speed and potentially a fuel economy hit.
Drag on the transmission - I simply don't believe it

Lou

 

Yep, it was a very popular mod on the original BMW X5s (E53) - unknowingly, I bought a 4.8is secondhand, with this mod already done, and I was blown away by how quick it was - until I vmaxed it on the autobahn and hit the rev limiter at about 135mph.... Then it dawned on me....

 

Apologies, I didn't mean to offend anyone. I'm well aware of how changing rear gearing works in most applications. I also love this thread and the mod itself; I've been rooting for everyone involved.

I was just hoping to toss in another data point that could be helpful because every car mod has some form of risk, major or minor. I don't think you guys are going to blow anything up, but it might be worth some extra vigilance and/or definitely getting a transmission tune when those become available to make sure everything's as happy as it can be.

 

^^^^You didn't offend me - However, my reply might have offended you

Lou

 

IMO, Both MPalmer and Lou's points - both are educational. I am not doing this mod but having an understanding of these is valuable to me from knowledge perspective.

 

After many months of reading this thread, I've also decided to take the dive with this mod on my 2018. I'll report back on prices, performance, etc. I have fresh PS4s and 93 is on tap here, so I'll try to document 0-60s before and after under those "ideal" conditions as another data point

 

Very interested in objective, quantifiable before/after comparisons!

 

@javrabbit had some great data points. I'm thinking at my elevation and with an otherwise stock setup I'll hopefully have good data. My favorite mods are the ones where you could believe the car is OEM, so this seems to be perfect for me. The only other "mods" my car has is a dash cam and wireless android auto lol.

Only issue I'm having now is trying to get Dragy to connect to servers - any recommendations here for a good app to measure 0-60?

 

Slight hiccup - My local dealer has reversed course and let me know, albeit politely, they'll be unable to do the diff swap due to risk/liability. Now I suppose I'll need to find a Lexus specialist in DFW 😁😅