streetzlegend

iTrader: (8)

So I hear these are the same transmissions. I am wondering if the internals are improved on the altimas since they are almost 10 years apart. A 4th gen 4sp auto is already pretty strong so it makes me think if any improvements were made. Does anyone have any info on this, Harold?

t6378tp

iTrader: (69)

I think the fd is different

grey99max

iTrader: (12)

Yup, the 2005-2006 2.5L 4AT transmission has a 4.4x FD compared to the V6 and earlier Altima trannys which are 3.7x FD. They (2005-06 Altima) are only available in an open-differential, no LSD version. I had mine welded up solid. The 4AT guts are basically the same through the entire series - including internal gear ratios. If you remove the Altima bell housing you can attach the 4th gen Maxima bell housing and put it in your car - if you use the longer shifter-wire cable from a 2000-2001+ 4AT and splice it into your 4th gen wiring. Same solenoid and shifter functions thru the series, but the shifter cable will require the same mods needed for any 2000+ 4AT put into a 4th gen. Nothing major...

The 2005-2006 2.5L Altima transmission has any final internal upgrades made to the 4AT, because that's the last years that the 4AT was sold. IPT built one for me and it was great. King Streetz, hope this helps...

streetzlegend

iTrader: (8)

Thank you for thise details. I am thinking of my next track visit being another stock auto with transgo but this time do the band upgrade for 4th gear shift, i never did it when i installed the tranago. I think i can get a few runs at full power before it starts to act up. I was curious if the newer altima 4at were identical parts and clutches for this next auto i put.

grey99max

iTrader: (12)

As far as I know, the guts are the same - just that the quality of internal parts were improved over the years. I just checked with car-part.com for 2.5 Altima 4AT transmissions in Florida, and there are boat loads of low-mileage transmissions for a few hundred dollars in your state !! Like $450 for a 50K transmission... Do it! The lower FD ratio means you will be into 4th gear much faster, and a modded torque converter will be a bonus.

Much closer are the 10s, Jedi Master King Streetz !!

streetzlegend

iTrader: (8)

I actually want to stay away from 4th as much possible. It seems thats the weak link, then it takes 2nd with it. So I really wanted to increase tire height, but that would hurt ET probably, so I may extend rev limit just enough to get passed the line before 4th. I am taking a short break but when I get a gap of time I am doing putting another auto and the bad *** edge converter ill be getting(going to be able to lock it at our power!).

ABIGBRAIN

iTrader: (1)

http://www.nicoclub.com/Greg/ratios.html

All the info I gave to Harold a while back for his Altima tranny. Sentra tranny will also do the job.

http://www.wallaceracing.com/Calculators.htm

I use this site and their vast array of calculators to get a good idea on different setup possibilities

streetzlegend

iTrader: (8)

Thanks for the info. The sentra uses thr same RE4F04 trans?

ABIGBRAIN

iTrader: (1)

2004-2005 SER'S have the same granny as do the 2.5 Altima's up to 2004 I believe. They both have a better FD ratio for your application with 26" tall slicks.
2005-2006 2.5 Altima's have a 4.425 FD that Harold mentioned earlier.

grey99max

iTrader: (12)

Hey,bud... how's that monster engine you built?? Reading these last posts gave me an idea - if StreetZ uses the 4.45 FD transmission with a modded torque converter, wired like mine with 12 volts going thru a switch directly to the transmission solenoid, then when he tops out in 3rd gear, flip the switch and engage the carbon clutch in the torque converter and start climbing up the RPM tree again. I kinda remember that doing that drops the RPMs by 30%, and that might let him go thru the traps with the tranny still in 3rd gear, if he's worried about blowing 4th gear.

Engaging the torque converter clutch that way really locks it up hard - I've tested it maybe 10 times in WOT in 2nd and 3rd gear, and it bangs hard when engaging. Just a thought.

On my new engine, I'm busy flycutting the DLC lifters one at a time to clear the new JWT cams. Kinda tedious work, and using 50lb test springs is the only way I can rotate cams with the HR heads sitting on a bench. The new HR springs are STOUT.

Later...

streetzlegend

iTrader: (8)

I am thinking, I am going to have to accept having to get into 4th gear even with longer gear and locking the TC. Edge uses upgraded band like you said, carbon, so it should look up really nice. I dont mind the sudden hard lockup as long as its not breaking stuff. I think its probably best to lock it at low rpm since the converter is less efficient at higher RPM, meaning at low rpm the difference in RPM is less so the lock shouldn't be as drastic.

What is the driving experience with the diff welded? How do you think it would be with no power steering and city/shopping center driving?

I just cut my lifters with a dremel lol, at least the car drives lol

grey99max

iTrader: (12)

You could just re-wire the TC clutch solenoid from a battery connection to a doorbell toggle or switch and try engaging it at different points. I think that locking the converter drops the RPMs by around 20% -- and if you leave it locked when you slow down, the engine will stall out.

A locked spool is a sum-bichz when turning any corners, and hard even with power steering. Without PS, it's all about arm strength. The car wants - insists - on going in a straight line. I do it because racecar, but taking wide corners are the rule, and backing up is a different form of excitement. Driving around on 275/50/15 MT drag radials like I do makes it worse. If you mount normal street tires on the front, it's not so bad.

I'm also using a Dremel mounted in a drill press stand, with an rotary orange stone, to cut down the center bump a bit. I used an outside digital micrometer to measure for and make incremental changes, based on first mounting the JWT cams in the heads and using feeler gauges to find the gaps for each valve, then grind to remove the extra. I finished the right head last night. So far the JWT cams are either right on for minimum clearance or up to .005" too tight, so I can cut down the OEM DLC lifters. I have a batch of new lifters of maximum height (8.40 mm) in case I need a new one. These JWT cams have monster lobes !!

streetzlegend

iTrader: (8)

Oh i already have full control of the TC, for years iv had it in a switch, i always race with it unlocked since it wont hold. I can also lock it when ever, i have stalled just like manuals locking it at a stop by mistake. Sounds like i won't weld the diff lol
Thats the same method i did. Doing small increments at a time checking with micrometer.