Any Ideas what would cause 2nd gear to slip in a new BTE powerglide? I am thinking our trouble was in the linkage but I want to rule out as much as possible. The car is a 1435 lb front engine dragster with an alcohol/nitro injected 425 Nailhead. Shortly after making the shift to 2nd the rpms start to come right up faster than the wheel speeduzzled: . Would this possibly be the band adjustments. The fluid is not burnt and shows to be at the right level after 12 passes. Thanks for any help
Any ideas on second gear in our caro No: . I would like to get past 100mph in the 1/4 and first gear is done at around 400 ft. I am just letting the 6800rpm 1st gear run the cars speed, which is the same 1/8-6.01et or 1/4-11.37et @ 98mph. Any help would be great. I am hoping for something easy:laugh:
Could it be that your revs are dropping below the converter stall speed. The revs then have to rise again until the converter stalls.
Rossco I am using a 3500 stall converter from TCI. The car weight is 1435 race ready. We can launch quite well(1.30 60ft.) even at 2000 rpm, due to the very light weight of the car. When you shift to 2nd, it hits hard and then the revs come up like you were spinning the tires, but for almost 1000ft. . I had been just leaving the car in the second gear position and keeping the revs at 6800. Our 1/8 and 1/4 speed is within 1-2 mph. I was not sure if it was a band adjustment due to the fact it only seems to effect 2nd gear. If the fluid level was not correct(although it show it is) I would think that 1st gear would also slip,wouldn't it.
I'm no expert on auto boxes but as I'm about to strip a TH400 I have been doing a huge amount of research. Yes band slip would account for it. Unfortunately until you tear it down you wont find out. Just thinking aloud here....what dictates how hard the shift occurs? Perhaps you need to lessen the 'impact' of the 1st 2nd change. That's about my limit on this one......anyone else want to chip in?
Rossco thanks for the help. I had spoken with a person that was about half track when we made a few of our runs. He asked if I was just using 1st gear and only trying out 2nd gear . He thought he heard the shift to second, only to hear the engine rev back up like it was in 1st right after the shift. I am not a tranny guy so if I don't hear of anything to check I will just bring the Rail over to the tranny shop next week, and have them take a look. I am still hoping to fix this myself with the boards help and direction. Thanks again for any help.
I'm in a big hurry here and didn't read all of the post. But, 1. The ban is for LOW gear only, so if it is half way adjusted correctly, that's not your trouble. 2. High gear is the drum clutch pack applied. If it is sliping in high, its a bad lip seal in the piston in the drum, a cracked drum or the sealing rings on the back of the pump where the drum fits over that are broken or leaking. If it has always been doing this since installation, I'd say it is the lip seals cut or the sealing rings on the pump support broken or a cracked drum. If it was good at first and then started slipping, I'd say it is burnt clutches in the drum. Another thing to check is line pressure with the trans hot. If it is low, it will cause the same thing. Not much to a glide but can be a pain if screwed up on assemble. Good luck, I have to run. Jim Netherland
Jim thanks for the info. The tranny had only 4 runs on it when I got it. The trans guy I got it from put in a Dedenbar cased trans in his altered and sold me this one. I can take this tranny out in about 10 minutes so is there anything I can check or should I just take it out and bring it to the local tranny shop? Thanks again
John, if you're not "set up" for an automatic teardown & reassembly, it would probably be prudent to head for someone who knows Powerglides, preferrably someone who knows about the usual mods as well. Devon
put it on jack stands and hook up a pressure gauge to the case fitting... fire the engine in neutral, shift to 1st, 1st and reverse should have the same pressure, it will be higher than anything else, at least 180+, then shift manually to drive and see what happens.. park and nuetral should be the same reading as each other as well, probably a little lower...
If it isn't shifting into second at all, it could be the vacuum modulator, vac line, or the governer. Is it a Buick ST 300 trans, or a Chev Powerglide? Like the others suggested, check the line pressure first. If it's low, could be a leaking fluid supply (filter), bad pump, or other internal leak. When I first put my Blue '66 together, my first 1/4 runs were at the GS nats in 1983.... With the 2.93 rear, I could run mid 14's using ONLY first gear, and revving to nearly 6000 rpm! I only did that once....it was, after all, a long drive home.
Thanks for the responses. I was planning on putting in a trans pressure gauge at some point. I guess there is no time like the present. Do I just T into the cooler line and run to the gauge? Thanks again.
Nope! I don't know where, but there's a port that's plugged off on the outside of the trans that you tap into for pressure readings.
Alan not much progress due to work schedule . I have leaned out the motor a lot since Bowling Green and the throttle response is unreal:eek2: .The engine should be using about 1.5- 2 gallons of methanol a pass as it is set up now. I will not be racing for the next few weeks due to the weather is too HOT at the tracks we go to. I am getting a second powerglide for the car in the near future from a possible new sponsor. We will be running the car at the Air Museum runway over the course of the next few weeks for testing. The runway is about 20 miles from the house:TU: . I will keep everyone that is interested posted as we progress toward our goal. The 425 is a 65 block and that has an aluminum Powerglide bolted to it.
