4wd transmission proplems, broke gearbox then diff and transferbox updated with broken gear selec Options

[tufy]

2 months ago i broke my gearbox, because i coulnt find stronger gearbox for daily use, i installed a 2nd hand standart gearbox which was slightly shorter... after i installed this g.box, traction of my car was more like front wheel drive.. (%60 front and % 40 rear. thats what i feel). then when i make a quick start i started to feel that rear diff. is slipping gears. after 3000 km i break my rear differential.
does anybody knows if ratio of g.box diff ratio and rear diffrential ratio change it make diff stress and broke easier. or my diff. broke from too much power.
simply;
does it make proplem in a 4wd car if i have shorter ratio gearbox without changing diff..
sorry for my bad english. and thanks for your help.

This post has been edited by tufy: Apr 17, 2007 - 9:49 AM

[Kwanza26]

2 months ago i broke my gearbox, because i coulnt find stronger gearbox for daily use, i installed a 2nd hand standart gearbox which was slightly shorter... after i installed this g.box, traction of my car was more like front wheel drive.. (%60 front and % 40 rear. thats what i feel). then when i make a quick start i started to feel that rear diff. is slipping gears. after 3000 km i break my rear differential.
does anybody knows if ratio of g.box diff ratio and rear diffrential ratio change it make diff stress and broke easier. or my diff. broke from too much power.
simply;
does it make proplem in a 4wd car if i have shorter ratio gearbox without changing diff..
sorry for my bad english. and thanks for your help.

Hmm... interesting question. It can potentially cause a problem if you don't have matching front and rear final drives, which is what I think you're reffering to. Say for example the front transaxle, or transfer case is a 4.1 ratio and the rear is a 4.7... then you'll get some slippage in the rear because it'll try to turn a bit faster than the front with the same load. Hmm. Speaking from building trucks... this wasn't a problem because the transfer case and and front diff operated for the most part independently... but with an AWD transaxle... I dunno. I'll have to research this... heheh...

[tufy]

Hmm... interesting question. It can potentially cause a problem if you don't have matching front and rear final drives, which is what I think you're reffering to. Say for example the front transaxle, or transfer case is a 4.1 ratio and the rear is a 4.7... then you'll get some slippage in the rear because it'll try to turn a bit faster than the front with the same load. Hmm. Speaking from building trucks... this wasn't a problem because the transfer case and and front diff operated for the most part independently... but with an AWD transaxle... I dunno. I'll have to research this... heheh...

this is exactly what i ask... but probaply if i feel like car has more traction at front, then front transaxle ratio should be bigger.. am i right?

[Kwanza26]

this is exactly what i ask... but probaply if i feel like car has more traction at front, then front transaxle ratio should be bigger.. am i right?

Yes... or taller final drive... ie: smaller ratio.

[Nibbe]

It might be also of the power. Like one of my friends audi s2's 4wd wouldnt take more than 400whp. Just a thougt.

[Driveby]

ST205 gearboxes tend to be weak over 500bhp, rear diffs are also prone to break when launched at these levels, fensport now run a dog box with a cusco rear diff assembly if I remember right to prevent the failures that plagued them with the Corolla.
I think the gearboxes are £5000 each but they havent had one fail yet to my knowledge.

[Hanyo]

As long as your front and rear differential are idential, you should not be experiencing problems.

I think, the main problem your having is caused by the shorter geared transmission you put in. The lower gears increases the stress on the rest of the drive train. The added stress will cause the weakest link to breaks, that is why your rear differential finally gave out.

Another problem I can think of is, If the center differential of your new transmission is more direct. This would mean the power is not split correctly between the front and rear wheel. This would increase the stress to the rear differential.

[tufy]

ST205 gearboxes tend to be weak over 500bhp, rear diffs are also prone to break when launched at these levels, fensport now run a dog box with a cusco rear diff assembly if I remember right to prevent the failures that plagued them with the Corolla.
I think the gearboxes are £5000 each but they havent had one fail yet to my knowledge.

thanks for good info guys..
i called fensport a few times and mailed them about their dogbox, also mailed to a few people that are using this dog box. the proplem is i use my car every day at least 50 kms. and some times i use it hard they dont recomend me a dogbox for daily use. i am working on an other solution. like sequrential shifter with straitcut gears and secronize engagment. unfurtunately there is no sequrential shifter kit for our cars.
now i am planning to buy a cusco 1.5 way rear lsd. its available for st205. but the think is, are they made for my old gearbox or the one i have now:/ i mean will the ratios fit with cusco lsd?

This post has been edited by tufy: Dec 23, 2006 - 9:31 AM

[playr158]

Tuffy, u do know you can have a squential transmission made for your GT4....not just a kit which the shifter is what makes it sequential but a full stronger tranny.

http://www.xtrac.com/mainindex.htm

[Coomer]

i am working on an other solution. like sequrential shifter with straitcut gears and secronize engagment. unfurtunately there is no sequrential shifter kit for our cars.

Wouldn't a tranny with straight-cut forward-driving gears be pretty loud, like our cars are when they're in reverse?

[tufy]

i am working on an other solution. like sequrential shifter with straitcut gears and secronize engagment. unfurtunately there is no sequrential shifter kit for our cars.

Wouldn't a tranny with straight-cut forward-driving gears be pretty loud, like our cars are when they're in reverse?

i dont think that anybody can hear this gear sound because of my exhoust and turbo sound
the gears will sound exactly the same like reverse gears, like rally cars have.. but it seems that i have no other chance. i dont want to try semi helical gears and break it again to decide that i need strait cut.

i mailed xtrac also. they dont have.. only one company said ' İ dont remember name now' we can build it for you. but still you will need some work to make it fit to your engine and it will coast arround 15000 usd exp. shipping and fitting

[doGGy]

i am working on an other solution. like sequrential shifter with straitcut gears and secronize engagment. unfurtunately there is no sequrential shifter kit for our cars.

Wouldn't a tranny with straight-cut forward-driving gears be pretty loud, like our cars are when they're in reverse?

i dont think that anybody can hear this gear sound because of my exhoust and turbo sound
the gears will sound exactly the same like reverse gears, like rally cars have.. but it seems that i have no other chance. i dont want to try semi helical gears and break it again to decide that i need strait cut.

i mailed xtrac also. they dont have.. only one company said ' İ dont remember name now' we can build it for you. but still you will need some work to make it fit to your engine and it will coast arround 15000 usd exp. shipping and fitting

Way too much money IMHO. I can ask around - cuz we have a Nissan Pulsar GTR here with 700hp, and the company what build it ordered the gearbox for it somthere in Switzland, its a Sequensional gearbox (kulachkova like we call it here ) and the price was like 5000Eu for it.

Let me know Tuf, i will ask around if you need this.

[tufy]

here is how my diffrential broke.
gears are in perfect conditon.

[Gary]

You should definitely talk with Pat C.
He is doing well over 700 awhp and over 600 ft-lb of toque.

[tufy]

You should definitely talk with Pat C.
He is doing well over 700 awhp and over 600 ft-lb of toque.

who is pat C.?

[Gary]

Head over alltrac.net
His user name is alltrac101
http://alltrac.net/phpBB2/viewtopic.php?t=18354
He does not post much though. May be you can start a thread there.

[snakeloa]

Keep us updated on this Tufy and good luck

cheers Joerg

[tufy]

i had one more proplem last week. i broke 3rd gear selector. its not only upgrading gears and shaft, i need stronger fork selectors for sure.

[Wolf_tm]

2 months ago i broke my gearbox,

Tufy,

what did you broke exactly in the gearbox the first time ?

I found a good shop here in Italy, they told me they can make stronger helical synchronized gears for the E154 box... but I saw you already resolved with sqs ?

[Wolf_tm]

You should definitely talk with Pat C.
He is doing well over 700 awhp and over 600 ft-lb of toque.

Not now...

over 800 awhp at 36psi, but he uses a 42psi map for drag race...