BIGBOS

I am most likely doing this conversion, but do not have the cash to get a rearend as well...I've been figuring that I will have to drive the car like an 80 year old grandma for about 5 months...

How long will a stock 10-bolt, with an auburn posi, w/4.10 gears last on a Nitto with a TH400 as the main drive line??

Would a full WOT run blow it to pieces? <img src="images/icons/confused.gif" border="0">

PaiN

Lot of variables.

The main thing it's going to boil down too is how hard you are hitting it.

If your are...
1) Taking it to the track, and launching on a sticky surface
2) Using a T-Brake in your T400
3) Using a high stall converter
4) Doing the above in a full or near full weight car.

don't expect it to last long.


Sure many members here have had their stock rears live a long time, but most of them are running reduced weight as well. I'm sure there are a few out there that have had 10-bolts last a long time...but I wouldn't count on it if your gonna do the stuff listed above.

MacGyver

iTrader: (5)

Bigbos,

I kind of went into this in my other post but let me go into some detail here.

When I put my TH400 into either first or reverse from park. I really slams it into gear and the whole car shakes and you hear a big clunk from the rear end. When driving on it the shift from first to second is pretty violent and most of the time when I'm on my nittos on the street shifting from first to second will chirp the tires. The reason for this is that unlike a 4L60E the TH400 has full line pressure 100% of the time so no matter when you shift it it shifts as hard as it can. A 4L60E is computer controlled and the line pressure is controlled by how much throttle you're applying. In comparison to a T-56 a TH400 would shift like you pushed in the clutch, put it into the next gear, and then just dropped the clutch not slipping it at all. That's the best way I can think of to compare the two. As for a pretty stock 10bolt with aftermarket gears holding up behind a th400. It may or may not last long enough to save up for a new rear end. I personally dont know of anyone running a th400 with a 10-bolt. So I guess in all that rambling I just did my opinion is that a stock rear wont hold up very long at all with a th400.


L8r
Will

Trevor @ Texas Speed & Perf.

iTrader: (3)

From a 60' standpoint, remember that the TH400 has a taller 1st gear in it than the 4L60E. (2.48 vs. 3.06) So, with the same gear and converter setup, your 60' time will be slower. FWIW, I had a TH350 in my '98 T/A 383 for a short while, and the best 60' I could muster was a 1.67. This was with 3.73's and a Yank TP4600. I was at a sticky track on ET Drags, so it wasn't spinning. Prior to that, I had a 4L60E w/ 3.42's and a Vig 4000 that netted a 1.53 60' time. I was even pushing more power when the TH350 was in the car due to updated heads, 1.8:1 RR arms, and LS6 intake. I was trapping just under 121 MPH vs. my previous 117.5 MPH w/ the "old" setup.
The part-throttle shifts can be violent as mentioned above, and that will definitely take its toll on a 10-bolt, especially with 4.10's. I think the rearend will go south from something other than a 60'. 1.5's are pretty common for A4's with converters and a 10-bolt.

MacGyver

iTrader: (5)

Trevor is correct with the gearing issue. You most likely wont 60' as well with the TH400. BUT on the contrary you wont be rebuilding the TH400 often either. I dont know of anyone cutting 1.5x 60's with 4l60's that have lasted very long. Also you can swap out the 1st gear in the TH400 like I did. I had a 2.75 first gear put into min and you can go as high as a 3.0 first gear with it. The cost to swap out the first gear is almost 500$ but with what my plans are for the car/motor setup this was worth the 500$ to swap it out. Also you can offset the loss of gearing from going from a 3.06 to a 2.48 somewhat by changing your tire size. And I think the last point that needs to be made is that bigbos is not swapping from a 4l60 he's going from a T-56. I cant remember what the first gear in the T-56 is but i know it's not over 3.0 When I had the T-56 in my car the best 60' I could get on nittos was a 1.92. Granted this is not the best possible with a 6speed and nittos but I didn't have the cash available if i broke stuff so i was easy on the car off the line. The first time out with the TH400 on nittos I netted a 1.71 60'. One last point is that with the TH400 unlike the 4l60 you can get a transbrake which will definately help out in the 60' department with being able to use the true "Full Stall" of the converter. With my converter on the footbrake it stalls to about 3300 before the tires start spinning. On the transbrake it stalls to 4100. Yank sells "Built" 4l60's for around 1800 at the cheapest. my TH400 with the transbrake, and swapping out the first gear (480$) was only 1450. Just some points to ponder


L8r
Will

BIGBOS

Thats interesting...well I guess I will just have to be real nice to it, I can imagine the shifts... <img src="gr_eek2.gif" border="0">

Thanks for the info