Technical > Dan Dishon's Transmission Den

Powerglide Questions

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lake_harley:
I built the Powerglide for my FED using Carl Munroe's book "Powerglide Transmission Handbook" as a guide. When we did a few mild test passes with the car last week it seemed that it was more "sluggish", and took more throttle to move in Low than it did in 2nd (Drive) or Reverse (valve body converted to manual only, providing I did things right) The converter is a 10" Boss Hog unit that is considered 5000 stall but I was told by them that with the low HP of my car it would probably stall at about 4200 RPM. The PG doesn't have a trans brake....we're foot braking it. In general it just seemed it took less throttle in the pits to move in Drive or Reverse gears than it did in Low gear.

I have several thoughts on what might be causing the sluggishness, if it indeed does have an issue;

A) Perhaps nothing is wrong and it's quite normal? I've never had a light car like this with a high stall converter.

B) The Low band isn't holding? I can and will double check the band adjustment.

C) When I built the transmission I tried various steel and friction disc stacks to set clearance in the high gear clutch pack. After trying several combinations they all seemed to go from really loose to borderline tight. I finally assembled with the clearance borderline tight thinking that there might be a tiny bit of friction disc break-in wear on the new discs and that it might quickly  loosen up. I know the high and reverse clutch packs "slip" in low gear, so that might be adding too much drag if either clutch pack is tight?

D) I have read that Type F ATF provides a sharper shift than Dextron ATF. That sounded like a positive thing so I used Valvoline Type F fluid. Could it be that the Type F fluid is creating "stiction" in the clutch pack(s), especially with tight clearances? If that's a potential issue, are the fluid types compatible enough that I could drain and refill the transmission a couple times to dilute the amount of Type F fluid in the transmission?

Perhaps there could be other issues, or there might not be an issue at all, so I'm open to comments and suggestions.

Thanks, in advance!

Lynn

JEFF/21C:
without being there it's hard to analyse, type f trans fluid is what you should use.clutch clearance should be on the loose side. band adjustment is very important every 6 runs.should feel 1st engage just as you would a street car

masracingtd1167:
How tight is the clutch pack ? I would go no tighter than .060 for high gear or reverse !

JEFF/21C:
no .060 should be good, the min is .010 x the number of face plates 

tcoupekyle:
In my experience, it sounds like nothing is wrong. Convertor in both my cars starts moving as soon as I put it in gear. Both run FTI convertor both stall fine. One is 2600lbs 615hp 5400stalland the other is roughly 1000hp and 1600lbs with about 4000-4500 stall

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