Can I run dex6 in my th400.

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Originally Posted By: joegreen
Thanks for the info on the atf. Ill run by my napa tomorrow and see whats up. As far as the dual feed mod you have convinced me not to do it. Also I am trying to do this rebuild on the cheap. Is it really necessary to rollerize the tail shaft?


It is not necessary if the locating tabs on the Case that locate the 3-tab selective washer are in good shape. Be sure to set the "Rear unit end-play" within factory specs.
 
I ordered 24 quarts of the peak ATF from Napa. How much do you think the shipping will be?
 
Originally Posted By: joegreen
I ordered 24 quarts of the peak ATF from Napa. How much do you think the shipping will be?


Hope you had luck getting your Peak. My Napa couldn't get it.
 
Originally Posted By: Lubener
Originally Posted By: joegreen
I ordered 24 quarts of the peak ATF from Napa. How much do you think the shipping will be?


Hope you had luck getting your Peak. My Napa couldn't get it.
They were supposed to call me today and let me know whats up but never did. Might have to give them a call tomorrow.
 
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So I got the transmission somewhat torn down. The case is empty but I didn't take anything else apart. Anyway someone has been in the valve body area before. It only had 2 check balls. Also some of the valve body bolts and threads in the housing are stripped. Anyway where the reverse band rides I think its called the reaction drum it has grooves in it you can see and feel from the reverse band. Is that ok or does it need to be replaced or machined flat again?
 
I called Napa today and they said my oil should be here in a day or two. I bought 24 quarts of ATF so I hope it goes through. Even if the shipping is a little pricy it should still be good deal at 90 cents a quart
 
Originally Posted By: joegreen
So I got the transmission somewhat torn down. The case is empty but I didn't take anything else apart. Anyway someone has been in the valve body area before. It only had 2 check balls. Also some of the valve body bolts and threads in the housing are stripped. Anyway where the reverse band rides I think its called the reaction drum it has grooves in it you can see and feel from the reverse band. Is that ok or does it need to be replaced or machined flat again?


The Reaction Carrier (Front Planet) band surface is pretty rough from the factory, If it has 3 grooves worn in it from the Band lining.....Replace the Carrier, '91-'94 4L80E reaction carriers will fit & have a harder band surface, Later 4L80E carriers will not fit because a difference in the Lo Roller Clutch.

The Lo Reverse Band rides on the Carrier even with it released causing the wear your seeing, CK Performance sells a spacer that moves the band apply pin away from the lo reverse band & DOES NOT affect band clearance! This mod alone frees up to 10 horsepower (My own testing on a '57 Chevy on a Mustang dyno) http://www.ckperformance.com/View/TH400-LOW-DRAG-REAR-SERVO-SHIM

Use a new grooved TH400 band, No Kevlar or a 4L80E smooth band, The stock TH400 band is the toughest band available.....Proven on 1800 horsepower trans brake door slammers!
 
Originally Posted By: clinebarger
Originally Posted By: joegreen
So I got the transmission somewhat torn down. The case is empty but I didn't take anything else apart. Anyway someone has been in the valve body area before. It only had 2 check balls. Also some of the valve body bolts and threads in the housing are stripped. Anyway where the reverse band rides I think its called the reaction drum it has grooves in it you can see and feel from the reverse band. Is that ok or does it need to be replaced or machined flat again?


The Reaction Carrier (Front Planet) band surface is pretty rough from the factory, If it has 3 grooves worn in it from the Band lining.....Replace the Carrier, '91-'94 4L80E reaction carriers will fit & have a harder band surface, Later 4L80E carriers will not fit because a difference in the Lo Roller Clutch.

The Lo Reverse Band rides on the Carrier even with it released causing the wear your seeing, CK Performance sells a spacer that moves the band apply pin away from the lo reverse band & DOES NOT affect band clearance! This mod alone frees up to 10 horsepower (My own testing on a '57 Chevy on a Mustang dyno) http://www.ckperformance.com/View/TH400-LOW-DRAG-REAR-SERVO-SHIM

Use a new grooved TH400 band, No Kevlar or a 4L80E smooth band, The stock TH400 band is the toughest band available.....Proven on 1800 horsepower trans brake door slammers!
The rear servo shim looks pretty cool. With the shim would i need a gasket for each side of the shim?
 
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Im having a hard time finding anyone that sells 4l80e reaction carriers. I would like to compare prices from different suppliers. Can i just get my reaction carrier turned on a lathe and then adjust the reverse band apply pin?
 
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Originally Posted By: joegreen
Im having a hard time finding anyone that sells 4l80e reaction carriers. I would like to compare prices from different suppliers. Can i just get my reaction carrier turned on a lathe and then adjust the reverse band apply pin?


I would not, Longer TH400 apply pins are not the easiest thing to find (Different than a 4L80E)
 
Originally Posted By: clinebarger
Originally Posted By: joegreen
Im having a hard time finding anyone that sells 4l80e reaction carriers. I would like to compare prices from different suppliers. Can i just get my reaction carrier turned on a lathe and then adjust the reverse band apply pin?


I would not, Longer TH400 apply pins are not the easiest thing to find (Different than a 4L80E)
So I went to a machine shop and i was talking to the guy about getting the carrier turned on a lathe. He said i should just leave it the way it is and run it. He said that if he got rid of the grooves it would change the grain structure on the surface of the carrier and that it would cause the band and carrier to wear quickly again until they mated together. So i am just going to leave it be. On a side note i called my napa again about the atf and they said they never ordered the oil and could not order it because there supplier didnt have any. Its a little annoying when they said it will be here in a few days and they never even attempted to order it.
 
When I put the transmission back together I want to put it together in one day. I tried looking but i cant find anywhere where i can get shims for the front and rear end play. I would like to have them on hand so i dont have to order stuff when the trans is going back together. Thanks
 
I included a link to Rear Unit & Reaction Carrier end play shims in a earlier post, Click HERE

Bringing the REAR into spec Will bring the Sun Gear Shaft & Main Shaft up in the Case, The Forward Hub sits on the Main Shaft so that will tighten front end play. Just FYI.

Pump to Forward Drum selectable Thrust Washers & new thrust washers for the rest of the unit.... HERE

DO NOT use the .128" selectable! If you have that much end play after bring up the rear & new thrust washers......Something needs to be corrected!
 
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Cool thanks. I took the oil pump apart today to measure specs and replace the bushing the torque converter rides on. Anyway I have a straight edge so I was able to measure the flatness of the two half's of the pump. The base of the pump where the gears go has a flat surface but the other half of the pump I was able to fit a .002" feeler gauge under the straight edge mostly near the center where to pump gears go. The manual I read says to get the surface machined flat if you can fit a .001" feeler gauge under the straight edge Should I get the surface machined flat? Also I was measuring the pump gear clearance to the side of the housing they ride in. The large outer gear has a clearance of .004" which is in spec but the smaller inner gear that the torque converter spins has .009" clearance which is out of spec. The housing that the gears rides in looks fine and doesnt show much wear. Everything seems smooth and there are no lips from the gears spinning. I want to know what is a good next step. Should i buy a new set of pump gears and see if the clearance closes up to within spec? Here are some pics so you can see what i am talking about.





 
Your pump looks really good, TH400's with miles on then will have pump gear tooth wear. I replace the pump gears on every build.

It has 5 bolts around the pump pocket... .002" is not an issue!
 
Originally Posted By: clinebarger
Your pump looks really good, TH400's with miles on then will have pump gear tooth wear. I replace the pump gears on every build.

It has 5 bolts around the pump pocket... .002" is not an issue!
I thought that the 5 bolts might help suck the cover flat I just hate knowing that it could be better. I am going to see how much my machine shop will charge to true up the surface. Ill get a new set of gears and see if the clearance gets better. Where do you get your gears from and are there any differences in gear metallurgy or something? Like i can find new gears on ebay for a little less than $20. Are those ok? I measured my gears with a caliper and i need the .7270 gears.
 
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Aftermarket gears vary greatly in quality, GM no longer manufactures them, But NOS gears can still be found at dealership parts departments. On a stock pressure/low RPM build.....The "off shore" gears will probably be OK.

I use teflon coated gear sets, But most units I build are high performance, I know this is not in your budget but here is a link...... http://www.ckperformance.com/View/TH400-TEFLON-COATED-PUMP-GEAR-SET


There is no published specification for the overall height of TH400 pump gears; however production pump gears should measure in @ .7265” to .7275”. The TH350 has selectable gear thickness's.......The aftermarket just lumps them together.
 
This is the gear set I purchased http://www.ebay.com/itm/281492635185?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT. The description does not inspire confidence but I couldnt really find many other .727 gears. Im surprised as popular as the th400 is im having trouble finding parts. On a side note I made this tool to compress the springs in that clutch pack that came out pretty sweet.
 
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