Th400 upgrades

Dirt700 · Feb 28, 2019

I found out my 3rd gear is out after 4 rides. When you shift to 3 it's like it goes into park, locking up tires and all. I called Ed at ptc, he built it for me, and said it sounds like 3rd gear sprag broke. 1,2, and R work fine.

Since it's a pita to get out, what are some other upgrades I should do, without spending 5k. Put in a 300m input and drum? Bigger sprag? Main shaft?

kmcminn · Feb 28, 2019

Dirt700 said:
I found out my 3rd gear is out after 4 rides. When you shift to 3 it's like it goes into park, locking up tires and all. I called Ed at ptc, he built it for me, and said it sounds like 3rd gear sprag broke. 1,2, and R work fine.

Since it's a pita to get out, what are some other upgrades I should do, without spending 5k. Put in a 300m input and drum? Bigger sprag? Main shaft?

Ati case?

Dirt700 · Feb 28, 2019

Re: Re: Th400 upgrades

kmcminn said:
Ati case?

I have a regular hd case right now, Ed said it should be fine unless I start racing. I would like a Reid or ati, but I need the internals to hold together first. If I end up breaking case I can swap over the good internal stuff

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Dirt700 · Feb 28, 2019

kmcminn said:
Ati case?

Not everyone has that big baller money like you and Broady booyang

kmcminn · Feb 28, 2019

Dirt700 said:
Not everyone has that big baller money like you and Broady

I wish i did.

smbroady82 · Feb 28, 2019

Dirt700 said:
Not everyone has that big baller money like you and Broady

nah, I'm just financially irresponsible :dblthumb:

tallnate · Feb 28, 2019

I ran a fairly built 400 in my prior rig for about 8 years and never had a failure. I'd say definitely upgrade to the big sprag. I'm no transmission builder so I can't attest to which upgrades are more important than others but here's the list of upgrades mine had.

High pressure valve body.
~Billet intermediate shaft.
~Billet input shaft & drum assembly.
~Roller bearing thrust.
~Forward & direct 7X7 clutch packs.
~Reinforced five pack intermediate clutch.
~Modified direct drum with heavy duty 36 element sprag that is 3 times larger than the 34 element sprag.
~Billet steel forward hub.
~Deep aluminum pan kit.
~475 Heavy duty spiral lock case trimmed for clearance. (case was trimmed for clearance so that 4l80e bands could be installed because they're supposedly a lot beefier than th400 bands)

Dirt700 · Feb 28, 2019

Re: Re: Th400 upgrades

tallnate said:
I ran a fairly built 400 in my prior rig for about 8 years and never had a failure. I'd say definitely upgrade to the big sprag. I'm no transmission builder so I can't attest to which upgrades are more important than others but here's the list of upgrades mine had.

High pressure valve body.
~Billet intermediate shaft.
~Billet input shaft & drum assembly.
~Roller bearing thrust.
~Forward & direct 7X7 clutch packs.
~Reinforced five pack intermediate clutch.
~Modified direct drum with heavy duty 36 element sprag that is 3 times larger than the 34 element sprag.
~Billet steel forward hub.
~Deep aluminum pan kit.
~475 Heavy duty spiral lock case trimmed for clearance. (case was trimmed for clearance so that 4l80e bands could be installed because they're supposedly a lot beefier than th400 bands)

Thanks, I'm going going to see what most of that cost. Definitely thinking bigger sprag, and drum and input and intermediate. Hopefully I can get that plus regular rebuild stuff for $1000-1500

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mrdrinksalil · Feb 28, 2019

Sprag upgrade for sure, but none of that other fancy extra clutch stuff matters if pressures and clearances ain't right. Takes a pretty big motor to break the input and outputs.

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