Any Glide experts?

[Razor]

Need to ask the experts

I have a glide behind a turbo'd 348 SBF and my problem is on the 1-2 shift my boost spikes hard and the converter drops more than usual. Example I shift at 6800 and it drops to 5100. The more power(boost) I put to the tranny, the worse it gets. meaning at lower boost levels I spike less on the boost. I had the converter 10 inch transmission specialties XHD unit sent to them when the tranny broke the planets in Dec thinking I had bent the fins on it.. they checked it out.. said no prob with converter.. and had them stall it higher.. back to square one.

So my question is.. is there something within the transmission(valvebody?) that can hold the car back on the shift on a glide? Meaning I know 2nd is a band.. can something not apply/release correctly to create this condition?

Seems when when I use the transbrake its worse on the RPM drop and the harder the drop, the worse the spike is on the shift.

I think I blew a head gasket last night when it spiked over 26 PSI.. running 16-17 PSI flat down the track and on the shift it spiked to 26 PSI. Earlier in the day, it was running 16 PSI would only spike 3-5 PSI.

In higher gear after the shift, the boost is flat just as its in 1st gear.

Car also noses down when it shifts on power. Takes time for it to recover.

Sorry for the winded post.. need help.. Just ordered a new converter on Friday and dont think its going to fix my problem.

 

[Razor]

This was one run Sat that it behaved perfect.

So if the converter was the problem.. would it fix itself?

 

[BlownV6]

On my blown dragster I see similar graphs as the last 2 , with the boost spiking up after the shift. I attribute this strickly as to the blower still producing x amout of cfm and the motor slowing down using less cfm , thus the spike in the boost number. The first couple shots you have there look really funky and something is defenetly not right there!! Your RPM should not be showing 2 steps in drop at the shift!! Not sure what would cause this but I think your on the right path. One thing I would check is the shifter linkage and/or the shifter device to make sure its not somehow to slow on the shift or going past the second gear detent for a moment , although either of these would normally cause a spike in rpm by showing a neutral position for a split second. You could be correct that the valve body is holding 1st and 2nd on together for moment. Not a trans expert by any means so now Im subscribed to this post. Good luck Mike

 

[Razor]

The first graph shows a spike from 16 to 26 PSI. Motor died after that pass.. dont know yet..but think it took out the HG's. Spins over with no compression..

The worst I had seen the spike until that point was a few lbs.. 3-5 max.. that pass it jumped 10 PSI.

The shifter is properly adjusted. I'm starting to think its valvebody related.

Thanks for posting.. got to keep digging

 

[opeltwinturbo]

Very few of us run glides. I believe your 2nd gear band is going south. In the Opel I shifted (Shiftnoid) my Rossler glide at 7,600 @ 31# boost. RPM dropped to 6,900 and 25# boost. 1st gear ratio is 1:80. Car weighed #2,700. I doubt the valve body would be pushing both 1st and reverse unless your transbrake was failing or you were accidently hitting the transbrake button while shifting. I also broke a set of planetary gears after 300 passes. Now sounds like a good time to freshen the trans while redoing the head gaskets. I also sent you a PM.

 

[Razor]

John thanks for chiming in. I know the Glides and Buicks are taboo. But there exists tons of knowledge on this board. Mine has the 1.80 straight cuts, updated clutch packs, updated servo, etc.. after talking with my 2004r trans guy he believes there could be overlap as the issue. Example like if the band was too tight. Meaning it has to release to get the car into 2nd gear. If its hanging.. example like binding in the case.. it can cuase that.

One thing I noticed was I tried going around the problem. What I did was hammer the car in 1st gear and right at the shift lift.. shift.. and then nailed it again. Didnt do it. If I stay in gear and shift at 6600-6800 it drops to 51-5200. If I lift/shift/nail it pulls from 6k on 2nd.

Since this is a different case, different pump, different planet/clutches/servo/ input.. the only thing it has in common from the previous trans is the valvebody.

Think its time for a new valve body Now what kind/what brand/etc.. is a question. My builder suggested the TCI piece..

Thanks to the datalogger i'd never find something like this.

When you have a case thats 25+ years old.. a valvebody thats ??? years old.. stuff happens. May save up some bread and invest in a newer HD case.