Toyota R series gearbox - R150 / R151 - R452 Dyna 5th gear swap - Pirate4x4.Com : 4x4 and Off-Road Forum

From reading this thread, if you've got a 95+ R150/R151 tranny, this 5th gear mod almost seems like a no brainer for us 5speed guys looking for better hwy fuel economy?
200 bucks in parts for a 30% OD reduction vs the stock 17%

Almost looks like this swap could be done without dropping the trans. Remove D shafts, split the tcase, and remove a crossmember if necessary....


Am I missing something?

Seems pretty straight forward, logically it makes sense, I'm interested, I plan on doing some long hauls with my rig and the OOD would be nice.

I wonder how a 6speed Supra R150 internals would play, if that's even possible.

Back when I had my MK4 Jetta TDI, fifth gear swaps were extremely common. Even to the point of there being multiple options of OD ratios. I've been interested in an upgrade like this for a while; even considering the plausibility of using a Marlin box to raise the final gear ratio.

I'm seriously considering biting the $200 bullet and ordering these gears up. I've never dove that far into a transmission, but at least everything is laid out nicely in the write up on pirate4x4.

The Supra's 6 speed box is called the V160, it's a different transmission altogether. You might be thinking of the Supras 5 speed R154.


H452 Dyna Fifth 0.69:1
R154 Fifth Gear is 0.753:1
R151F Fifth Gear: 0.836:1
R150(F) Fifth Gear: 0.838:1


Come to think of it, I wouldn't mind that OD in my Supra. R154 sits in my garage as we speak, waiting for Marlin crawler goodies

Ah dang you're right. I was thinking the R154 was the 6'er forgot about the V160.

I got a buddy at work who suddenly came out of the wood work asking me 20 questions when I put my bug Marlin sticker on my box, apparently Marlin is well known in the supra world too for their bullet proofs transmissions.

Of topic, what year Supra?

Marlin is definitely the way to go in regards to R series transmissions. The R154 in the MKIII Supra is pretty much identical to the truck transmissions so the upgraded truck parts do wonders.

Assume you have an R154 Supra transmission you want to build to hold excessive amounts of power. Marlin Crawler makes billet, 100% contact style shift forks that are stronger than the original cast aluminum forks. They contact the shift collar/sleeve for the entire available contact area rather than the OEM style, which contacts only in two points, roughly 12% contact area if I recall. Slam those gears!

Marlin also makes upgraded chromoly thrust washers, which are commonly regarded as the weakest link in the R series transmissions. They also make speed sensor converters for installing the R154 into a newer Supra, if need be.

The R154 was sold in the US installed on 86-92 Supra 7MGTE motor only. The same trans was also found in Japan mounted to the 1JZ-GTE, essentially the exact same transmission but with a different bell housing.

In my case, I'm building my R154 for a 94 Supra turbo (which is currently auto). I got a used R154 that needs a rebuild. Swap the bell housing to the 1JZ-GTE style and you can bolt the R154 to the 93-98 Supra's 2JZ-GTE motor.

The V160 6 speed that is normally in these cars would be my favorite choice, but those transmissions sell for upwards of 6k used. Add in the price of a decent clutch and flywheel and you're well on your way towards 10 grand for a transmission swap.

A Marlin Crawler upgraded R154 is by far and away the best transmission you can have for such a low price. It's no V160, but it will handle just about all the power you can throw at it. The entire swap including every upgraded part, swap parts such as pedals and interior parts, fluids, and labor, will be roughly $3000 by the time it's done.

Another $200 for a longer OD sounds like a sweet deal!

So; who’s actually done this?

Because I need to rebuild my trans; so might as well do this as well.

Is there a similar thing for the W59 transmission? I've seen one person swap in the W58 (?) transmission from a Supra to get better on road driving, but I want to keep the low gearing for off road driving which I'm sure the Supra wasn't designed to endure.

Did you end up doing the 5th gear swap?

I'll try bumping this thread before starting a new one.

I'm in the middle of doing the 5th gear swap with part numbers 33046-25030 and 33336-25030 with my new Toyota transmission 33030-34100. Transmission is a R150F but it's technically for a 2000-2004 Tacoma w/5VZ. It will interchange and install without any issues.

The problem that I've run into is the 5th counter gear/synchro hub is a one piece design which means I can't swap the synchro hub that matches the rest of the transmission onto the new 5th counter gear. I think I will be able to use the 5th counter gear/synchro from my current transmission, but I was hoping to be able to have the new transmission reassembled and ready to go before I pulled the current transmission. Looking at some photos from another member, he had a 2 piece 5th counter gear so I think I should have a 2 piece one as well in my current transmission. In the photo with two gears the factory gear is on the left and the new 5th gear is on the right. Also included photos of new gear/counter gear and the one piece factory gear I'm currently dealing with.

On a side note, I did the math on the new gear ratio and according to the teeth count it should be a 0.711 gear ratio for 5th gear. Factory 5th teeth count is 26 and 47. New 5th gear teeth count is 23/49.

I also found a gear vendor that makes aftermarket gears with the correct synchronizer already attached: Your store. MODIFIED 5TH GEAR SET .711 FROM .838 It's an Aussie company, but they have a good reputation on that continent.

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Not sure if this is what you're looking for and I didn't read all of this thread or the yotatech one but, maybe this might help
R452 5th Gear in R150/R151 - YotaTech Forums

I've been referencing that, but no one has a one piece 5th gear like my new transmission does. The common method is to transfer the original synchro gear over to the new 5th counter gear.

After further research, R150/151 transmissions went from a 2 piece to a 1 piece 5th counter gear (33428-60031 new part number) in 2004. Since my new transmission was manufactured after that date I have the updated 1 piece design. It is possible to make the R452 5th counter gear work without modification, but requires all the synchronizer pieces associated with the R452. I don't have time to wait for all these parts to arrive so I'm trying to locate a used OEM 5th counter gear so I can swap the synchro portion over to the R452 5th counter gear.

For anyone looking for the R452 counter gear synchro parts here's the part numbers you'll need in addition to the R452 5th gear and counter gear:
33394-35040 KEY, SYNCHROMESH SHIFTING, NO.3 x3
90364-30009 Split BEARING (FOR COUNTER 5TH GEAR)
33369-35011 RING, SYNCHRONIZER, NO.3
33392-14020 FASTENER big spring for dogs x2
33395-35041 GEAR hub ring
33318-35050 GEAR counter shaft end
Amayama has them for about half the price of US Toyota dealerships if you can wait the extra few days for shipping.

There are very few of the 5th counter gear synchro hub out there under the original part number if I had time to wait. 33046-35090 but unfortunately the only one that I've found is shipping from Japan via eBay, and it's essentially the same price as buying all the synchro components to make the R452 synchro hub work.

This is quite the project! Best of luck with all of this, Patrick!

After finally completing and installing this swap I have some observations and recommendations to share.

1) If you are stock axle gear ratio I would not recommend this swap unless you do a good amount of 50+mph driving. The rpm drop in 5th gear from the ratio change has resulted in difficulty maintaining speed going up moderate hills between 40-50 mph. Lower rpm means less torque. From a gear ratio perspective it's the equivalent of driving with a true 36 inch tire compared to the stock 265/70R16 when in 5th gear.

2) It has the potential to be quite involved. I used a new Toyota transmission (dumb decision to pull it apart but I'm not that bright). There's several differences between a new R150F and a used one. Mainly in the 5th countergear. Old 5th countergear is two pieces vs new 5th counter gear being 1 piece. 5th gear required the use of an acetylene torch to get the gear hot enough to pull off. Which was quite nerve wrecking as I was trying not to burn the bearing behind the 5th gear. There's a spacer between the 5th gear and the bearing that had to be shortened by about .060 of an inch. Luckily my brother has access to a lathe and removed .040 of an inch off and I used 80 grit sand paper and a lot of time to remove just enough material to get the bearing and retaining clip installed on the 5th gear shaft.

Who I would recommend this for.
If you are regeared for larger tires then this would give you a much more usable 5th gear assuming you have geared appropriately. With the 5th gear ratio change from 0.838 stock to 0.711 it would allow you to regear a couple steps further while maintaining 5th gear rpm's. For example if you regear to 5.23 then 5th gear rpm's will be comparable to 4.30 gearing (ONLY IN 5TH GEAR). In short you can get the advantage of more aggressive gearing for crawling/offroading, but have a usable 5th gear for highway speeds.


Would I do this again? Probably not. It was a lot more involved than any other writeup made it seem. Also very nerve wrecking to be opening up a new transmission and doing this. There was also the risk of having to disassemble the transmission completely to separate the 5th gear shaft completely in order to use a hydraulic press. Also, 5th gear was damaged in the process of removing it. Initial impressions are 5th gear is almost too low of rpm's to use in town driving. If I were running 33's and 4.88 gears then this would be a great mod to do IF I needed to rebuild transmission anyways.

THIS MOD IS NOT FOR THE FAINT OF HEART OR THE BEGINNER WRENCHER

EDIT: To clarify something, after swapping 5th gear you will now have the same gear ratio as our automatic counterparts 4th gear with the torque converter locked up. Automatics may only have 4 gears, but the torque converter makes up for that by being unlocked/locked. Torque converter unlocked adds torque multiplication to the equation for them. My previous 4Runner was an automatic and I was never able to get the torque converter to lock up in 4th gear lower than 44mph so that's probably a good indicator of where I should be shifting from 4th to 5th with my manual transmission and new 5th gear ratio.