What's up fellows? What do you think about a turbo 400 tranny? I just found out that is what is in my truck and was told that previous owner must of switched it. Anyway you know the steel line for the vaccum?, I was told that this tranny needs lots of vaccum so I figured I would either drill out or cut the end off to get the vaccum I needed. What do you think? Any suggestions would be helpful!! Thank You!!!! T.C.
The size of the steel line does'nt matter. As a matter of fact, a smaller tube will pull more vaccuum than a larger one. It's only going to pull as much vaccuum as your engine can produce. Make sure your vaccuum source is coming from the intake and not the carb. The intake provides a more constant source and where the brake booster pulls from. Also make sure the rubber lines at the end of the steel lines are free from cracks and splits ensuring a good vaccuum pull. If your after higher shift points try a adjustable modulator, it will a have red painted stripe around the body. The diaphram can be adjusted be turning in a screw located within the modulator, thus delaying the shift point.
The steel line is stock and all rubber lines are good. Also the line is hooked to the intake and the brake booster line is hooked to the back of the carb. The truck is shifting fine it just takes awhile to shift from 2nd to 3rd and when taking off from a dead stop it acts like it has a stall converter. So I think drilling out the end of the line or cutting off the nipple will increase the vaccum. I dont wanna burn up the tranny. Also note because of the new motor if I step on the gas too much it spins the tires. Motor has alot of torke and a really good cam...just can't remember what size. LOL!! tHANKS FOR THE INFO!!
The longer than normal shifts are'nt going to burn up the trans. Drilling the steel line is'nt going to help the shifting. Maybe a transmission service should be done to be on the safe side. A new filter and fluid would'nt hurt and also give you peace and mind.
Thanks, for the info but, I had this done when I first got the truck a few months ago. And I put a new module on it just about the same time I got it running. Maybe 2wks now, the gut at the tranny shop is the one who told me about drilling out the ends to begain with, don't think he would bs me would he? Yeah okay maybe he would but all I can do is try right? If the motor is running at higher rpms wouldn't this cause the tranny to shift different? And what kind of other problems will this 400 cause me if any? Are they good or should I be on the look out for a 350?
well in my opinion i would ditch the 400 and go for a 350 anyday but thats just me. you will never go wrong with a 350 and they are very easy and not to expensive to build if need be. but again thats just my opinion, good luck which ever way you decide to go
In stock form, the TH400 is a much better transmission than the TH350. That's why they used them in high torque applications (behind big blocks). They're getting a little expensive these days and I'm sure if you wanted to replace it with a TH350, you could get a pretty good price for it. Either way, I also recommend an adjustable modulator. They're cheap and easy to install.
I can't disagree wth THAT !! The TH400 will allow you to make significant performance modifications to the motor, OR go up to a big block without needing to re-think the trans.. The TH400 would be a better choice for towing if you need that. Val
If the modulator isn't enough, try Rhoads anti-pump lifters. They will gain you at least 2-3 more inches of vacuum. They smooth out the idle of bigger hydraulic cams, but act like solid lifters in higher rpms. I used them in bomber class racing to get over the 15 inches of required vacuum @ 700RPM.
