Transgo Shift Kit Install TH400 Turbo 400 Hydra-Matic 

I'm not a fan of the TransGo kit. I made a video later and replaced it with a B&M kit.

The way I installed that kit it had really harsh DOWNSHIFTS. Fairly weak upshifts. I took it out and replaced it with a B&M kit that works great. I have a video on that. The car has a seemingly stock converter in it so it gets great upshifts. The looser the converter the less you feel the shift.

@headflowinc so if you have it in first gear and floor it it will swift to 2nd when the time is right. will it go thew all the gears and the sifter is still in first

@@louisgreenberg5384 no, it will go into second gear, I have never seen one go into third while in low 1.

The governor shifts it to 2nd, so if you want it to shift at higher RPM you need stronger springs in the governor or lighter flyweights.

Exactly! Defeats the purpose of having a Hurst Dual Gate shifter, if you can’t hold the gear manually. The TH-400 is engineered to shift up automatically at around 3,400 RPM in order to safeguard the Tranny and engine.

Had same issue, was a split in the vacuum line. Check you have Vac where the tube plugs into the modulator at idle.

I think I would have liked it better if I installed the "race" line pressure spring. It was replaced with a trusty B&M Transpak. The harsh downshifts were gone after this.

Heres what the troubleshooting section says. Take the belts off and run it to be sure the noise is from the transmission. If not then could be oil pump cavitation for a number of reasons. Could be a bad converter or front pump assembly malfunction. Get the book How to work with and modify the Turbo Hydra-matic 400 transmission. It's worth its weight in gold.

@@Oldsmob455 thank you so much I really appreciate your help the plans for the 69 Firebird is a 400 engine that I am picking up this weekend and I am picking up a turbo 400 transmission that has been gone through but of course I would love to learn how to fix these transmission which I have on both of my Firebird and I picked up a original 400 hood for the 69 bird so that's the plan will make a video as soon as I can once again thank you

@@Oldsmob455 hi my Firebird brother today I dropped the pan on the Turbo 400 oil look good filter looks good I just changed the filter and the oil on this transmission less than 5 months ago once the car was ready to be driven on the road I was a little low on fluid so I topped it off I did what you told me to do take off the belt and definitely it was the transmission whining so once I was done I turned on the car let it come up to operating temperature the whining noise did go down a little less noise but if you put the car on low gear and hit the gas the whining noise is louder I guess I will have to be rebuilding this Turbo 400 thank you for all your help if you ever need help finding parts for your Firebird believe me I know a lot of people and you have been a big help to me so I will be willing to help you thank you

It worked fine and didn't slip. It's satisfactory for now.

now its there going to engage quicker and stop that soft mushy gear shift for pussys that burns up clutches for comfort..... you know i always have to have something to say :)

Yes, the B&M transpak.

Downshift was harsh. Upshift sucks. If I was to use this kit again I'd stick in the "race only" pressure spring.

Check out one of my latest vids, 1973 trans am last start 2020. I take it for a ride and bark the tires in between gears.

@@Oldsmob455 I have been told transgo is conservative on the shift. Do you remember how big you drilled the b&m plate? I think it calls for 3/16 on both feed holes. I had a b&m transpak in a th400 and I liked it, it did bust two bellhousings, but I'm not sure why. I think I had the drivetrain angle all screwed up because I put it in a 79 cutlass and made a double hump cross member hour of a chevelle cross member. I put the shift kit in my buddies 79 cutlass after I went back to a th350 and he never had any trouble with his 400. I honestly just don't know why it was busting bellhousings in mine and not his. The b&m transpak was great.

@@inscoredbz As I recall the transpak comes with the drill bit. I saw a bellhousing on a th400 break once behind a wheel standing nitrous injected 750hp ish motor with slicks on the back.

How to Work with and Modify the Turbo Hydra-Matic 400 Transmission by Ron Sessions. It can be found on Amazon.

Ron Sessions th400. Great book

thats the fix for the common leaky seal at the filter man.. commonly done, works great

Ok if you say so. I guess double oring on oil filter works great also. Generally if you have two seals on something then it will leak pass the oring. I will let you do that I’ll just keep to a single seal . Thank you for your input

Agreed. It is designed to only have one o-ring.

You’re re-tarded, it’s under vacuum not pressure. You need to double o-ring the tube on these or they leak air into the pump suction. You also use the screen filter, not a paper media one. You'll literally burn the tranny up at high revs because of lack of fluid to keep the clutches and bands clamped. If you want to fry the tranny when you’re racing with it do what you say.