I got my tranny in today....official follow up thread

I can't believe what a difference in performance a quick shifting tranny makes! I was also pleasantly surprised that my first TH400 tranny rebuild actually worked without any problems. I guessed that governor modification right on the money.....she shifts at 5,500 RPM exactly! (how sweet it is p )And the tires chirp on the full throttle 1-2 shift.......I love it! That '73 valve body I put in kicks a** .......this thing drops from 3rd to 1st all the way up to 43 mph! :Brow: Only thing I did notice is the part throttle downshift doesn't seem to work.......but with the SP I really don't need that anyhow....it still kicks down when I floor it.

I've gotta say, one thing I learned is when you rebuild a tranny, you MUST drive it around for a while to work the air out (I guess) because at first it was shifting too late and a few times it started out in 2nd gear from a stop. Also, it made a whirring sound especially at full throttle shifts for quite some time before that went away. (aerated fluid?) After driving it around for about an hour or two to break things in it ended up that it shifts perfect.......the shift timing is just where I want it, and the whirring noise seems to be gone. I'll take her for a drive tomorrow and see how it shifts when it's cold.

I panicked a little when I first started it.......it made a loud whirring sound for about 10 or 15 seconds (I guess the air had to be worked out of the oil pump). I wanted to circulate the oil really well before actually driving it, so I ran it with the wheels off the ground for a few minutes before actually driving it. Fearing the worst, it was quite satisfying to feel it shift for the first time. :3gears:

I want to say thanks to Mark, (dcm422) and everyone who offered advice to me in the buildup thread I started. Without your suggestions, I would not have known the tricks that I'm sure took you a long time of trial and error to learn. I don't even have to drop the pan on this thing, the only adjustment I had to make was to back the modulator out a few turns to soften the part throttle shifts a little......I don't think I could ask for things to have gone better than this. I'm just in awe at how much the performance of my car has improved......I've never been able to chirp my tires shifting into 2nd before. I took my wife for a ride and thought she was gonna have a coronary when floored it from 40 MPH :Brow:

I don't know what RPM the 2-3 full throttle shift is yet......I didn't want to risk getting a ticket. Maybe I'll get her up on the thruway this weekend and find out. :3gears:

 

congrats on the success! :beer funny you should mention the noises and aeration. My first auto trans rebuild was a C6 and it did the same thing. In fact, I got a mile away from home and it totally quit pulling. I walked home thinking I failed miserably, got another vehicle and went back to tow it. Just for kicks I tried it again and it moved in drive. I drove it home and opened a cooler line into a 5 gallon bucket and purged the air out. After that it shifted flawlessly. I still see that truck on the road with the same trans and I rebuilt it back in 1995 or 1996.

 

Congratulations on the tranny. Its cool to hear that it worked out great for you. I would also like to thank everyone who helped you, because I learned alot during that thread as well... :TU: :3gears:

 

:tu:

 

congrats on your tranny

so kool to hear tires chirp isnt it, hears one i had a 1974 buick century witha 455 in it with 342 gears automatic of course witha turbo 350 in it.when i would go up the merge to get on the highway i would always give her i would get a big chirp going into 2nd gear,about 44miles and hour and then at about 70 to 73 miles an hour shifting into 3rd gear i would get another squak. how bout that one. Ray
________
Help On Love

 

Joe,
Congrats on a job well done. :TU: Your part throttle kick down is likely still there, but you may not notice it unless you are going slow enough and the vacuum drops enough to make it happen. With an SP, going into high stall may raise the vacuum enough so that it won't kick down.
It also works best at speeds between 15-35 mph. If you are going faster than that, governor pressure may be high enough to keep the trans in 3rd.
Also, you adjusted the modulator for smoother shifts which effectively raises vacuum. Try some low speed acceleration without going into the SP and see how it goes.
That 43 mph kick down is something ain't it. :eek2: Gotta love them late model VB's!
Give it a good shake down and enjoy.

Great Job :TU:
Mark

 

Congrats Joe! :TU: :3gears: Glad to hear everything worked out for you! It is an interesting thread, I even learned a few things! :TU:

 

I was thinking......maybe I'll just crank that vac modulator back in a turn or two. That way when I slowly pull in to the local cruise nights I can chirp the tires :Brow:

In a way it's a shame that whirring noise went away too....it kinda sounded like a blower :laugh:

 

This should be the link to the thread if I did it correctly.

SP rebuild

Joe,
The whirring noise is not a good thing to have. :error: It was basically the pump sucking air on startup and the fluid being airated. It went away and should stay away. If it comes back, you may have an issue with the "O" rings on the suction pipe or a poor filter. Sometimes that metal pipe can be installed upside down and then the alignment is not correct. Don't think it will be an issue as things sound fine.

BTW, you owe me a ride if I can make it up to Batavia in July. :3gears: Am planning on being there, but can't enter a car as I am not a BCA member. Will likely go up there to see things with the Northeast guys.

Mark

 

You are correct......I took her out for a spin this morning, and noticed the part throttle downshift working perfectly. At speeds below 35, just like you said.....that's where they are needed most. I expected them to happen at higher speeds from 3-2, but like I said, with the SP converter you don't need it. I'll bet that will happen while climbing up a steep hill though. :TU:

 

Someone had asked me in a PM what mods I did to this tranny so I thought it would be a good idea to summarize what I did right here.

1) From the factory, most trannies have 1 wavy plate in each clutch pack for smoother shifts. I left the wavy plate in the forward clutch (first gear), but replaced it with a flat one in both the intermediate (second gear) and direct(third gear) clutches.
The forward clutch applies when you put it into drive or L1, so you want that to be a smooth engagement. I used Raybestos "waffle plates" in the forward and direct clutches also, they are more durable. You must use smooth clutch plates in the intermediate clutch or it may squawk when it applies.....they gave me some plates called "high energy" which were a step up from stock.

2) I removed the spring from the front accumulator on the valve body to make a quicker 2-3 shift.

3) I drilled 2 holes larger on the VB seperator plate, I will post a photo in this thread illustrating that. You could also use a B&M kit, but why spend the money if you don't need to? I should also note that I left out the 1-2 check ball for a quicker 1-2 shift, something that B&M requires you to do also. (I'll post a photo later in this thread)

4) I installed the heavier yellow pressure spring in the front oil pump to make more mainline pressure. That will make the clutches apply harder, but the downfall is that it imposes slightly more wear on the converter hub which drives the oil pump. I chose to take my chances.

5) I wanted a higher 1-2 full throttle shift point, b/c the stock shift was around 4600. By modifying the primary weights on the governor, I was able to raise it to 5500 to match the mild cam I have in my motor. Just by luck I hit it right on the nose the first time. I should note I used the slightly lighter springs from a #14 governor.
B&M makes a kit for this, but it's trial and error and again.....why spend the money and go through all that work if you don't have to? I will post a photo of what my weights looked like after I ground some meat off them. I used finishing nails just like the factory did when I put it back together.

6) I used a valve body from a '73 TH400 tranny, b/c it allows part throttle downshifts and lets the tranny drop from 2-1 at much higher full throttle downshifts than the original VB did. I added a heavier spring to the 1-2 accumulator valve also. This is explained in detail in another thread. (click here: http://www.v8buick.com/showthread.php?t=68002 )

7) By using that later VB, I was able to use the newer style filter, but you also must have the newer pan which is slightly deeper than the original pan, and requires the newer pick up tube also. I think it's better b/c it's cheeper and better by design. Only thing I did notice is that it seemed to take longer for the air to bleed out of the tranny than the original style did......maybe that's just a co-incidence though.

8) The most important thing in this rebuild was having a factory manual to refer to for torque specs and stupid things like what way does this part go in? Also the other thing that really helped was to familiarize myself with EVERY part before putting it back together..........like the thrust washers and spacers and needle bearings. Leave one of those out or put one in the wrong place and it will spell real trouble.
By doing a pre-assembly mock up of each and every part first it really helped. Also, I was very organized when I took it apart by keeping all the parts in order. Some of them are identical in size but different.......such as the clutch pistons and springs which are the same size but not interchangable. Also, the direct clutch and the forward clutch are different and could easily be switched around. The manual illustrates how to tell them apart by the location of the check valve on the direct clutch, something the forward clutch has in it's piston instead.

One more most important thing.......if it's not clean enough to lick, it's not clean. And I used petroleum jelly and a small brush to pre-lube EVERYTHING when assembling it.
Only the clutches I soaked overnight in tranny fluid, that's a must.

Here's a photo of how my governor weights looked......this made my 1-2 full throttle shift point 5500 RPM:

 

The stock seperator plate was drilled out. The hole in green was drilled out to 1/8", the one in yellow was drilled out to .140"-.156" (works in conjunction with leaving that accumulator spring out of the piston in the valve body). The hole outlined in blue must be the same size as the one in the gasket, which was 7/32". If you get a B&M plate, essentially it's the same thing as doing this. :bglasses:

 

This tranny originally comes from the factory with 6 check balls. I left one out, but since I'm unable to draw arrows on my photos, all I have is this photo of where I put the five balls upon assembly. I can't point to the one that I left out for quicker shifts: ou:

 

I have the same 67 TH400SP with a transgo shift kit and a lter style VB.
My trans shifts at 4,500rpm at WOT but my SBB likes to be revved to 5,500rpm.
What would you suggest I do first to my governer to get it to shift at 5,500?
Woul I be better off buying a govenor kit?
Thanks
Tim

 

Larry, I do have an extra governor from my other TH400 so that will come in handy! So do I need to use lighter springs and lighter weights?
Which should I try first?
Also I heard that you can adjust the modulator for small changes, which way should I turn the screw.... in or out?
Thanks again Larry!
Tim

 

Tim.......if you have an extra governor, you've got nothing to loose. You'll be pulling your hair out screwing around with all those weights and springs. I got lucky with mine and hit the 5500 shift piont right on the nose the first time. I used the stock springs from a #14 gov and used finishing nails just like the factory did to hold things together. I smooshed the ends flat with a hammer. Since your tranny is similar to mine, grind your stock secondary weights to look like this: :Brow:

 

If you've never seen what stock primary weights look like, here's a photo:

 

I forgot what the weights look like, I will tear into the old tranny tomorrow to look. Are you saying that there are two sets of weights, primary and secondary, if so how do I know which is which? Larry you mentioned change the springs until I get the 1-2 shift at 5,500 and then keep going lighter until I hit the rpm's on the 2-3? Won't that change the 1-2?
Thanks
Tim