That's just when mine broke. I think it was broke the run before because I heard a pop when I was backing it up after winning 1st round. I'm building another trans that will be used in a 9.90 car that I will eventually finish someday! But when I take the broken one out of the 10.90 car I will put this one in while I hope the other one is just a broken case.
Solid trans mounts are the number one cause of broken trans cases. Get a new rubber mount, no need for any HD crossmember. JW
I have a rubber mount and my cross member That I built but after putting those headers on that you sold me they fit closer to the floor so I had the raise the area where the Drag pipe extensions go under it. I could lay under it and push it up and down. Son I welded in a couple up pieces to stiffen the C channel in front and back of the cross member mounts cause you could see the frame twist when I pushed up on the trans. I thought maybe the rear of the trans is picking up during the run. I have 3 degrees at the rear of the drive shaft and 0 at the rear end flange so I thought 3 Degrees is where you want it. Should I drop the rear end to something negative?
Been talking to my Transtar parts guy and he thinks the green HD clutches would be better than the red Alto. Anybody tried both?
I got the Brake! It say to drill the 1/16" hole in the high drum. I take it that's the Direct drum with the sprag that goes out all the time?
Yup, it's a bleed hole for transbrake release. Pay close attention to your direct clutch clearance, I used to like about .075 for quick apply and long life. I think minimum is .050 max is .090.. You may have to machine your direct clutch piston to get it just right. I had good luck with Raybestos Blue plate clutches in the direct on trans brake 400, went about 500 passes between freshen, and even then I was replacing them "just cause I was there".. JW
I have lots of steels, sorted by thickness. Some swapping of 70, 90, and 93 mil thickness can get me there (anyone want some extra steels?). Bruce Roe
I found that a 4L80E has a direct hub with a .050 wider sprag. I'm going to ask the parts guy about it. Bruce where you located? These are all .090+.
Better price the 36 element sprag that goes on that 4L direct drum first.. as I recall, they are not cheap. If you worried about breaking a 34 element sprag, buy an aluminum direct drum. You will need some type of lathe to turn that piston down, if you can't come up with the correct stack up with various thickness steels. JW
2.75:1 and 3.0:1 low gear sets have been available for TH400s. I have one of each; both will be on E+ay one day. They seem to be fitted from other transmissions that used the ratio. I have had failures of both over high mileage usage. They wear out thrust bearings, make setting end play more difficult. I concluded the switch pitch converter did more for me at no risk, and removed them. Bruce Roe
They say the low gear sets have a weight limitaion. Does anybody know what that is on the 2.75? I checked the direct drum and it's the same as the one that the 34 sprag broke on the trans that's in the car now. But I think if I start the Burn out in 2nd the 34 should hold up. The trans guy here said it's cheaper to fix it every now and then compared to the high dollar drums and sprag assemblies. He said use the spiro lock on the sprag retainer also.
I just started to build the 400. 1ST the rear bushing. I'm opening up the channel per instructions here. How close do I get to the modulator valve hole? I measured on the flattest side of the divider and this is where I stopped.
Good up to the intermediate clutches. I left the second sealing ring off of the center support per the instructions for the Brake. Output shaft endplay spec .007-.019 and I have .010 so good there! I'm getting ready to put the direct clutch hub in and see nothing about a thrust washer. Jim do you know if there is one there?
It's amazing that guys don't try to build there transmissions cause it's easy if you know where the parts go and if you change it just follow directions. I am doing this Trans-brake trans for the first time and trying to do it right but when you need help it sucks trying to get a hold of someone to steer you right. Am I the only Buick guy here besides Jim that has done this? I had to go to you tube to answers for some of my questions.
Nope, my first dive in was a TH350 in the family van in 1983. It's all we had to drive, so I knew it had to be right. No internet back then, just a chassis manual from the library and a couple of my Dad's friends from his Buick days over the telephone. Since then I've done all the trans work myself. You'll do fine! Devon
I'm checking pump end play and I have a pack of thrust washers for the pump. Some are plastic and some look like gasket material. I need one of the paper ones to get below .024 clearance. Could I put 2 plastic ones in there to get the clearance or just use that paper one?
