Venting on transmission woes.

[Heckeng]

As some of you know, I had a tranny issue a couple weeks ago when I lost 3rd and then 2nd gears. Turned out to be an internal linkage problem (linkage loosened up and fell apart). I fixed that, but decided to take the tranny out anyway because it was leaking quite heavily from the pump gasket. Believe it or not, this is where the story goes down hill. I got a new gasket for the pump, a new o-ring seal also for the pump, and a new converter snout seal. Got them all in and when I installed the transmission, I had virtually no second gear. I figured something internal in addition to the linkage was the problem. It turns out that O-Riley Automotive gave me the wrong gasket ! The pump gasket was missing one hole, that's it, it was identical other than that! My transmission guy is the one who found it. He went to the parts store (Carquest) to get another gasket for another tranny he was doing and got the same wrong gasket! So, be very careful if you are in the midst of rebuilding a th350. It seems like there have been some gaskets mis-packaged by the original manufacturer! I'm sure they are reboxed gaskets all made by the same company.

 

So, that wasted my first transmission by smoking the clutches that handle second gear. I decided to put in my old spare transmission. I took the broken one out and installed the spare only to hear it making some nasty metal on metal sounds. So, I took it out too. It turns out I broke my intermediate sprag and hardened race on that one. I don't know when that even happened! So I've had another one built and will put it in this week if I get an ATI valve body I ordered.

 

I've done a bunch of google searching and have learned some tricks to get a th350 to last a little longer that I didn't know earlier. The biggest two are:

 

1. Never do a burnoff into second gear and let the tires catch traction while in second. Either keep it in first, or go all the way to third.

 

2. Never downshift on deceleration from third to second gear. If you are going to downshift, goose it to get the tranny into acceleration then let off to decelerate.

 

If I had to guess, I'd say the first one probably broke my sprag/race, but who knows.

 

My monte has been on jack stands for about 2 weeks now while I've learned all of this. I'm of losing quality cruising time.

 

Thanks for letting me vent, even if nobody reads this

 

[Guest]

1. Never do a burnoff into second gear and let the tires catch traction while in second. Either keep it in first, or go all the way to third.

 

2. Never downshift on deceleration from third to second gear. If you are going to downshift, goose it to get the tranny into acceleration then let off to decelerate.

 

Humm that's intersting I'm an offender of both of those??? Well not so much the first one.... never really caught traction in 2nd doing a burn out, I do the burn out in first gear then shift to 2nd let off the brake and smoke the tires a little more then coast to the starting line.

 

Now on the 2nd one I do that all the time. going through the finish line at around 103 mph and with 3:31 gears my car don't slow down to fast so I usually pull it down to 2nd gear (save the brake a little) when I near the turn off road to the return road to the pits.

 

BTW I have had my tranny for over 13 years.

 

[Heckeng]

I don't know what to tell ya Robyn! I hope your luck keeps up.

 

Check out this link to the Chevelle forum, discussing th350 and th400 operations and weaknesses. Look for the long posts by Jakeshoe. Chevelle forum transmission thread

[Guest]

Hummm pretty intersting reading, I can see what he is saying about down shifting a 60 mph plus.

 

but the burn out deal still has me puzzled though, I've doing the same burn out method for years and nothings bad happened YET!! but then again I'm careful to not let it hook up in 2nd during a burnout though.

 

One thing I noticed he hit on is not!!!! to throw your trans into neutral at high speeds, I see a lot of drag racers do this and it scares the crap out of me every time I see it done, I seen a vega roll over and over because his trans locked up on him after he went through the finish line at around 125 and slipped her into neutral........ he was ok but man what a tough way to learn a lesson.

[Heckeng]

Update: Got the tranny back. It was rebuilt with a kit from Northern Auto Parts for $70 which is half price from my normal B&M kits. My builder said he had tried some of these kits and they come with more seals and it's the same name brand stuff in most other kits. The only thing I wasn't totally sure of was it did not have Red Alto and Kolene clutches and steels. One of these kits has already worked in a friends blown 70 monte that runs 10s for probably around 100 runs so far and it's still going, so it ought to be good for me.

 

In addition, I got an ATI valve body. It's a manual/automatic valve body which keeps Drive being automatic, but first and second gear are just that, either first, or second gears. Second no longer shifts from first to second which is different.

 

The transmission is shifting excellently, and the shift from 2 to 3 is unbelievably fast, just an interesting fact. The shift from 1 to 2 is quick, and harder than my old B&M rebuild, although since the valve body was replaced it's not a fair comparison.

 

Finally, I'm back on the road!

[Guest]

Congrats Scott!!!! BTW nice plymouth monte..

[Heckeng]

Thanks Robyn, that plymoth monte thing is an actual sign I found and bought that somebody had apparently screwed up! I thought it was funny so I bought it:-)