![]() ![]() ![]() ![]() The bellhousing machining was also changed drastically to accept this very different outer bearing race, and itbalso uses different set of shims for setting bearing preload. ![]() One other person had already attempted this swap upon my recommendation and found that the pinion shaft itself is 1 mm larger diameter than the older 5 speeds where that bearing presses onto the end of the shaft. The last 'gotcha' is VW changed the pinion bearing whose outer race presses into the bellhousing. This is why swapping into a 02J case is necessary, especially for the VSS. The challenges of performing this swap: this has 0A4 casing halves, meaning no provision for a vehicle speed sensor, there is no flywheel TDC hole with pointer, which is important for ALH timing belt jobs, and two of the three shift linkage bracket bolt holes are in the wrong location. So, for my purposes, this is an attractive solution. But, there also are plenty of people making a good amount of power in the 5 speeds with no real issue. The only drawback aside from the amount of work to swap cases is the fact this is a "weaker" gearbox than the MQ350s. You also aren't going to have selector failures like the MQ350/02M/02Qs are known for, not to mention the clutch hydraulics, especially the slave cylinder, are more reliable and do not require transmission removal to replace. This is also interesting because it means you keep the same shift bracket, same axles, starter and the much more affordable clutch and flywheels that the 5 speeds use. I like this because it means good used parts will be a lot more readily available in North American bone yards as opposed to the 02M 6 speeds that we did not get here for TDIs in the states natively. 1st is actually shorter still than the stock 1st, but it won't be super noticeable.ĥth gear is a smidge shorter at 0.77 va the stock 0.75, and 6th is 0.625. Same 3.39 final drive a Mk4 TDI uses, but has very close to identical 1st through 4th gears. 02A/02J/0A4 "MQ250" gearboxes are about as close to Lego interchangeability as it gets for their internal parts for a design that dates back close to 35 years at this point.Īfter looking up the 6 speed, I was pleasantly surprised at how great the gearing looks for a Mk4. The 0A4 is just an evolution of the 02J, which is itself is a mild evolution of the older 02A that dates back to the late 80s with the first Corrados. So, imagine my delight and surprise when I plugin the VIN of a 6 speed manual 1.4 TSI and see what transmission code it has, then look in the parts catalog to find out that this transmission is NOT a 02Q/MQ350 with the twin pinion shafts, but it is an MQ250 02S, which is effectively a 0A4 5 speed with another gear added to it. If you've driven up steep grades and had to slow down for slower traffic, you might appreciate more how a 0.658 5th can be too tall while the 0.97 4th is almost uncomfortably short in real specific situations like that. That gear spacing would at least help address the big complaint about installing a taller 5th gear, but having that large drop from 4th to 5th. In a mk4 TDI gearbox, generally you're going to see the following: Same 3.39 final drive, but taller 3rd, 4th and 5th gears. An earlier observation was made that 1.8TSI 5 speeds use some very nice gearing that would be great for a TDI as well. I've been looking at transmissions in the VW Parts catalog via lately just to see what's available in our market. This was news to me as the earlier 1.4s came with a 5 speed as their optional manual transmission. Poking around some used cars a couple months ago, I came across a 2020 Golf 1.4 TSI with a 6 speed. ![]()
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