Changing out 5th and 6th Gear?

[KaiPL]

Can you change out just 5th and 6th gear without messing with 1st through 4th?

I like the ratios for 1st through 4th, but would love to make 5th and 6th gear a bit more useful.

I think that the perfect set up would be to make the current 5th gear the top gear, and replace the current 5th gear with a gear half way between the current 4th and 5th gear. That way, I could tighten up the ratios between the higher gears, and won't get the bog when shifting between 4th and 5th at high speeds.

I know absolutely nothing about transmissions. Is it possible to just change 5th and 6th and leave the rest alone?

 

[Skip White]

Kai, what differential do you have in the car? Changing out the diff. to a 3.55 not only lowers the final gear ratio, but it puts all the gears closer together.

Skip

 

[KaiPL]

Kai, what differential do you have in the car? Changing out the diff. to a 3.55 not only lowers the final gear ratio, but it puts all the gears closer together.

Skip

I have the stock 3.07 gears with a Quaife diff.

I don't want to change the ratios of 1st through 4th. I like the ratios of the first 4 gears as they are. It's just 5th and 6th that bug me.

Kai

 

[fluffy]

Certainly. I'm sure these guys would be happy to help you out ( it'll probably cost you tho- ).

 

[KaiPL]

After some web searching, it looks like these guys also offer what I'm looking for.


http://www.rocklandstandardgear.com/RacePerformancefiles/frame.htm

Looks like their T56-018m is a stock Viper transmission, with closer ratio 5th and 6th gears.

Gotta save my pennies. $2400

 

[Chuck 98 RT/10]

Somebody recommended someone in AZ I believe that swapped out 5th gear.

 

[PhoenixGTS]

Somebody recommended someone in AZ I believe that swapped out 5th gear.

That was me. A few months ago the input cluster in my tranny broke. No way I am going to rebuild a tranny myself so I got a referral to a great tech named Alger at All Trans which is a huge rebuilder in Phoenix (owner used to have a GTS and Alger is an enthusiast). They had an already rebuilt Viper T-56 in stock for $1,550 or so, but I worked with Alger who got a shorter 5th and 6th gear kit from Rockland Gear in New York. It added $1,000 to my rebuild (almost all parts but Alger did have to turn down the shaft the gears go on) but now I have a .80:1 5th gear and .64:1 6th gear. I cannot say I would ever spend the money to do this if the tranny was not broken, but since I had to do a rebuild I can say the shorter 5th and 6th are awesome. Now I have a real six speed instead of a four speed with two retardedly tall over-drives. The car has 3.55 gears and with the stock size GEN II 18" rear tires the redline in 6th is right at 200 mph which means that 5,200 rpm is in the mid 170s which is as fast as my low-power car will ever hope to go. So now my top speed will be achieved in 6th rather than 5th like before. Plus, without N20 or boost, I will not have to shift out of 4th in the quarter mile. In other words perfect gearing. BTW, the short gears come from the Aston Martin version of the T-56.

A word about Alger. He is one of those rare guys you run into in the auto tech biz who really knows what he is doing, and also cares about it. He is such an up-to-date super tech that he is already rebuilding the new 7-speed auto box for Mercedes for their warranty work. He has rebuilt countless T-56 units himself. His rebuild shifts like butter and he was a pleasure to work with.

 

[Nadine UK GTS]

Kai, you need to contact John at [email protected] This guy has done much work with T56s and for Mopar performance; I was lucky to find him. I swaped out the 5th and 6th gears on my OE rear-geared '97 for the same reasons as you state. John was real helpful with advice, besides all the parts (the Vette ratio gears availble are not as strong, John uses Aston Martin gears) he will swap the gears out and sort your tranny if you need a decent place to, this guy knows his stuff you can trust him with your tranny, he may take his time but you will have no complaints over the workmanship and parts. You will like it, 5th and 6th can be made to pull good too!

 

[MAVERICK]

I also have the Quaife Dif. and you should try a car with 3.55 gears first to see if you like it.

 

[Phil]

Wow you racers are lucky! I've never even come close to the magic 5th gear on my car yet. The most I've used was the 4th gear..mostly city driving and highways...

 

[KaiPL]

Is the T56 transmission in the Gen III the same as the T56 in the Gen II?

 

[Skip White]

No the trans in the Gen 2 is positively different. I beleive the Gen 3 has a one piece main shaft. This is said to be a much stronger design.

There may be other little improvements. The T-56 is really a great trans. as they have very few problems. Vette, Mustang, Z-28, Trans Am, all run a lighter duty version of this trans.

Kai, seems like I heard the 5th and 6th gear cluster in a T56 is not very strong, and as a matter of fact, it has a high failure rate, so should you change out these to a lower gearing, I would hope you are able to build up this weakness.

Skip White

 

[KaiPL]

No the trans in the Gen 2 is positively different. I beleive the Gen 3 has a one piece main shaft. This is said to be a much stronger design.

There may be other little improvements. The T-56 is really a great trans. as they have very few problems. Vette, Mustang, Z-28, Trans Am, all run a lighter duty version of this trans.

Kai, seems like I heard the 5th and 6th gear cluster in a T56 is not very strong, and as a matter of fact, it has a high failure rate, so should you change out these to a lower gearing, I would hope you are able to build up this weakness.

Skip White

Thanks

I just confirmed this on the Tremec page.

http://www.ttcautomotive.com/English/products/T-56.asp

Looks like the Gen III transmission (the TUET 1806) is rated 100 lb feet higher than any of the others.