Need some advice on H2U5 tranny

[wagon-r]

Swapping the final drive ratio is just swapping out the gears. In fact, I think you can buy aftermarket final gear ratios that are steeper yet.

Another option to get the 4.266 final gear ratio is to buy an Accord wagon manual transmission. They had the exact same 1st to 5th gear ratios as the sedan, but came with the 4.266 final drive instead of the 4.06. However, there weren't many of them made and I've been looking for one for a year without success. Tranny codes are H2U4 (4th gen) and P2A4 (5th gen).

However, swapping 5th gear from an Accord to a Prelude tranny is not as straightforward. 3rd-5th gears are designed as a set, so swapping 3rd-5th would just be a gear swap. However, the Accord 5th gear is a bit wider than the Prelude 5th gear, so to swap 5th gear only you have to shave the Accord 5th gear down. People have done this. However, when I worked at Honda 10 years ago I had access to the powertrain experts and they advised against having this done, as the gear is case-hardened and shouldn't be milled.

[GXZ]

Swapping the final drive ratio is just swapping out the gears. In fact, I think you can buy aftermarket final gear ratios that are steeper yet.

Another option to get the 4.266 final gear ratio is to buy an Accord wagon manual transmission. They had the exact same 1st to 5th gear ratios as the sedan, but came with the 4.266 final drive instead of the 4.06. However, there weren't many of them made and I've been looking for one for a year without success. Tranny codes are H2U4 (4th gen) and P2A4 (5th gen).

However, swapping 5th gear from an Accord to a Prelude tranny is not as straightforward. 3rd-5th gears are designed as a set, so swapping 3rd-5th would just be a gear swap. However, the Accord 5th gear is a bit wider than the Prelude 5th gear, so to swap 5th gear only you have to shave the Accord 5th gear down. People have done this. However, when I worked at Honda 10 years ago I had access to the powertrain experts and they advised against having this done, as the gear is case-hardened and shouldn't be milled.

wow thanks for that info very good to know

[rainbowjizz]

Swapping the final drive ratio is just swapping out the gears. In fact, I think you can buy aftermarket final gear ratios that are steeper yet.

Another option to get the 4.266 final gear ratio is to buy an Accord wag gon manual transmission. They had the exact same 1st to 5th gear ratios as the sedan, but came with the 4.266 final drive instead of the 4.06. However, there weren't many of them made and I've been looking for one for a year without success. Tranny codes are H2U4 (4th gen) and P2A4 (5th gen).

However, swapping 5th gear from an Accord to a Prelude tranny is not as straightforward. 3rd-5th gears are designed as a set, so swapping 3rd-5th would just be a gear swap. However, the Accord 5th gear is a bit wider than the Prelude 5th gear, so to swap 5th gear only you have to shave the Accord 5th gear down. People have done this. However, when I worked at Honda 10 years ago I had access to the powertrain experts and they advised against having this done, as the gear is case-hardened and shouldn't be milled.

so if I take my prelude transmission and accord transmission to the shop, they would have a hard time putting the accord 5th gear into the prelude transmission? that's what I'm trying to achieve. I'm having a hard time understanding the difference between the final drive ratio and a 5 th gear swap. would it be easier to shove the guts from the prelude into the accord case?

[wagon-r]

Rear-wheel drive vehicles have separate boxes for the gears and the final drive ratio. Front-drive vehicles shove them all into the same box. The final drive ratio affects all of the gears - every gear also goes through the final drive ratio.

The Prelude and Accord manual transmissions are identical except for gear and final drive ratios. (Don't let anyone tell you the Prelude manual transmission is stronger - it isn't). So, all of the insides will swap over just fine. The only catch is that 3rd-5th were designed as a set and, while the set will swap over fine, the individual 3rd, 4th, and 5th gears were not the same thickness.

[rainbowjizz]

Rear-wheel drive vehicles have separate boxes for the gears and the final drive ratio. Front-drive vehicles shove them all into the same box. The final drive ratio affects all of the gears - every gear also goes through the final drive ratio.

The Prelude and Accord manual transmissions are identical except for gear and final drive ratios. (Don't let anyone tell you the Prelude manual transmission is stronger - it isn't). So, all of the insides will swap over just fine. The only catch is that 3rd-5th were designed as a set and, while the set will swap over fine, the individual 3rd, 4th, and 5th gears were not the same thickness.

So would swapping everything into the accord case fix the thickness problem? Or will the 5th gear be too thick regardless because they are the same? Or maybe the final drive out of the accord would do the trick?

[wagon-r]

Yes, swapping all of the gears (or just 3rd-5th) will solve the thickness problem. Only if you want to swap only 5th gear do you need to shave the Accord 5th gear down a bit.

[rainbowjizz]

Yes, swapping all of the gears (or just 3rd-5th) will solve the thickness problem. Only if you want to swap only 5th gear do you need to shave the Accord 5th gear down a bit.

I understand, thank you. Initially I thought " final drive" was the 5th gear... But I'm certainly not going to take those chances, I'm already kinda slim on money. No need to trash a transmission for no reason.