Taller 5th gear in an A543?

[Oldsmobiler]

Hey guys is it possible to change out only 5th gear in an A543? After driving a company truck for so long I forgot how much my Shadow buzzes on the highway in top gear. Also looking for a rebuild kit if there is one for this guy.

thanks!

Ante

[Directconnection]

Welcome to the forum!

I don't have the answers for you, the 543 I am not sure of the final drive. But I know it's relative to the 523/568 and there are still some parts still available for those models.

As for the gearing, some people have swapped out the ring gear setup of the 523 for the 568, I believe, for the gearing you describe, vs just a 5th gear swap.

I am not the tranny expert... but thought I'd chime in with a welcome to turbo-mopar!

[Vigo]

543s came with 3 different ring and pinion (differential) ratios that i know of, 3.5, 3.77, and 3.85. usually the 3.5s make everybody happy on the highway and the other two can get annoying, especially if you run shorter than stock tires. You can swap a whole tranny with the 3.5FD on it and it will drop in and run with no other mods. The gear ratio is stamped onto a metal tag top center of the transmission. You could take parts out of a donor transmission with the right ratio and put them into yours, but thats something most people who dont know transmissions shy from, and usually its extra effort unless the rest of the donor is unuseable in one whole piece for some reason.

As for just a 5th gear swap, all the 5th gears were almost identical ratio and there are no aftermarket sets so as for just swapping 5th, while it would be insanely easy if the parts were available, they just arent, so changing the differential ratio or just going with taller tires are your only options.

[Oldsmobiler]

Figured as much just thought I'd ask....you never know.

Yeah I've got the 3.77's in the car and man does it buzz on the highway. I'm actually running 16" pumpers with 205-55/16's and it really doesn't make that much of a difference.

How about this...is there a rebuild kit that I can get to redo this trans? The sycros are starting to go and its got 200,000 miles on the clock with everything still original - clutch too!

[Ondonti]

There still isnt much. the 3.77 5th is .71 and the 3.50 is .72

I wish there was a custom gear available.

[Vigo]

if such a gear set was made it could be used by a LOT of people on this forum because im pretty sure it would work on all 523s, 543s, and 568s as long as the shaft splines are the same. Because of how the transmission is made you could install a different 5th gear set very easily without taking the transmission out..

i think the 3kgt crowd got something like that done, but Ondonti would be more likely to know about that than me..

If there was interest in someone getting a project like that going id put my dollars up.

[Juggy]

Figured as much just thought I'd ask....you never know.

Yeah I've got the 3.77's in the car and man does it buzz on the highway. I'm actually running 16" pumpers with 205-55/16's and it really doesn't make that much of a difference.

How about this...is there a rebuild kit that I can get to redo this trans? The sycros are starting to go and its got 200,000 miles on the clock with everything still original - clutch too!


your only option would be to swap the FD ratio as previously mentioned, with a 3.50fd keeping your original gearset a good time to swap if u plan to do rebuild

[88C/S]

Check out these sites, they may have what you need http://www.drivetrain.com/newprocess5spfwd.html http://www.drivetrain.com/manual_kits/mrk100306.htm.

[Ondonti]

if such a gear set was made it could be used by a LOT of people on this forum because im pretty sure it would work on all 523s, 543s, and 568s as long as the shaft splines are the same. Because of how the transmission is made you could install a different 5th gear set very easily without taking the transmission out..

i think the 3kgt crowd got something like that done, but Ondonti would be more likely to know about that than me..

If there was interest in someone getting a project like that going id put my dollars up.

They recently got a dogbox built, but I think it has stock 5th gear or 6th gear in the 6 speed models.

I would LOVE a dogbox.