I have had my transmision rebuilt 7 times in the last year and a half and have only put 25,000 miles on the car during this time period, now my trans is acting up again. At first I thought it was my 3-4 clutch pack but I dont think it is. It would not shift out of 2nd and would act like it was in neutral. About a month has gone by and I drove it over to a freinds house and it was doing the same thing. I decided to do a burnout leaving his house and it shifted right into 3rd no problem.So I drove it for a couple of days and everything worked fine so I decided to change the fluid and filter and had a little sludge on the magnet in the pan. Well today I was off so I took it for a drive and every thing worked fine until I stoped at the store and when I left the damn think did the same thing. Is there a posibility the servo is sticking or could it be somthing else. Any help would be great.

 

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But honestly if you want to keep the auto get one that's been built up. I'm sure there's some people on here that have aftermarket autos that will chime in and give you good info on who's got the best. And the good thing is that they're about the same price as a good rebuild.

And if you want to go over the top there's a couple people on here that have done 4L80E swaps. I think it's basically the same as a TH400 except that it has an overdrive.

BTW, my auto took a dump at 91k. I got an M6 on ebay that had 175k on it. My car has 97k on it now, good ol' Borg Warner T56 still shifts flawlessly, especially after my B&M ripper shifter install today.

 

A 4L80E swap is completely uneccessary. They're big, heavy, and they rob HP. Most people I've seen do the swap end up regretting it. The 60E can be built to handle more HP than most are capable of producing...but...it takes someone who knows what they're doing to build one to hold up in a racing application.

Frank
CPT

 

Frank, what are the limits of one of your 4L60's? My current set up makes 443 rwhp/514 rwtq, but on my next rebuild I hope to up the numbers by at least 200hp/tq. Would your transmission stand up to that much torque with slicks? How much more hp does it take to turn a 4L80E than the 60? I know the 80 is quite a bit heavier.

I did the 4L80E swap because I tore up 2 700R4's very quickly--and that was just on the road with Nittos. Those were built by a well known company who said they should be good for 600+ hp. I didn't want to give up my overdrive by going to a 400 because I drive my car mainly on the street.

I like my 4L80 with manual valvebody, but now you have me thinking about the hp I am giving up and the extra weight I am carrying around. Besides that, with the steeper 1st and 2nd of a 4L60 I could go with a little less rearend gear.

I did go to your website and read about you and your business--good reading. Looks like you have had a fairly long and successful career in automatics.

Thanks.

 

With what is out there now (as far as HD Parts) the realistic HP limit on these units with a 10" or smaller diameter torque converter, is about 625-650 HP, in a 3,300-3,500lb vehicle.

 

you can count on frank if your getting a rebuilt, he just did mine alll the way from california i'm a happy customer of cpt.