Which trans for temporary use behind healthy torque a 2004R or a TH350?

64nailhead

64nailhead

Royal Smart Person
Dec 1, 2014
1,340
113
Upstate NY
Another option is my current 2004R with the CK shift kit, billet servo, 10 vane pump and a billet foward drum and welded shaft.
This ^^ is needed for it to live. The billet forward drum is a must. The stock input shaft will live at 500ft/lbs without sticky tires. But the upgraded shaft is cheap in the big picture of things. The CK billet sungear helps as well. You'll be $2K into a 200-4R to make it healthy IMO. But well worth it. Just don't lock it up under load.
 
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olds307 and 403

olds307 and 403

Geezer
Oct 14, 2008
6,122
113
Melville,Saskatchewan
This ^^ is needed for it to live. The billet forward drum is a must. The stock input shaft will live at 500ft/lbs without sticky tires. But the upgraded shaft is cheap in the big picture of things. The CK billet sungear helps as well. You'll be $2K into a 200-4R to make it healthy IMO. But well worth it. Just don't lock it up under load.
I have a feeling this was a recent rebuild, I won't know till I tear into it. I will probably add the wide low/reverse band as well. Just the base 2200 to 2500 stall converter so no lock up under full throttle. I won't be a hurry to swap in the 3.90 gears incase I need to pull it and go TH350 temporarily. Hopefully I can keep it around $1000 having a converter and deep pan. Just depends on what it is like inside.
 
64nailhead

64nailhead

Royal Smart Person
Dec 1, 2014
1,340
113
Upstate NY
From my understanding, the forward drum is the weak link, then the sun gear, then the input shaft. This assumes a 10 vane pump with boost valve, and enhanced servo and properly setup of course, so I've been told lol.

IMO and experience, line pressure is a premium due to the smaller clutches/components than the TH400/4L80 have. The only issue we have with ours occurs due to too much torque being applied at light throttle. It's the turbo thing that a NA or nitrous build/setup won't encounter.
 
olds307 and 403

olds307 and 403

Geezer
Oct 14, 2008
6,122
113
Melville,Saskatchewan
I am going to get the CK reman 10 vane pump, supposed to give 295 psi. The last time I added boost valves and 13 vane pump, had it lying around, a .500"/.296" boost valve with Transgo high rev pump slide spring and pump rings to a 2004R pump, it didn't work so well. The reverse pressure was good, foward pressure was a dismal 180 to 190, sliding soft shifts. I never checked the clearance and there is better slide spring options. I used a .555" boost valve, brought it up 215 to 220 psi, nice firm shifts. I will be using the CK Billet servo and CK uses the. 555" boost valve in their pump and their shift kit is supposed to be the best. This trans should have the hardened sun shell. So I will do the billet foward drum and welded on shaft from CK. I may consider the input but should be under 550 ft/lbs, maybe slightly under 500 ft/lbs. I will know as soon as I pull clutches from the foward drum, the condition of the trans. A new hardened stator is another questionable part getting replaced.
 
pontiac guy

pontiac guy

Master Mechanic
Oct 28, 2016
361
63
Royse City, TX
I have some TH400 cores for sale cheap. I'll ship you one. Doubt you will break that.
 
olds307 and 403

olds307 and 403

Geezer
Oct 14, 2008
6,122
113
Melville,Saskatchewan
I have some TH400 cores for sale cheap. I'll ship you one. Doubt you will break that.
The one wrecker I picked up a 2004R from had a bunch of BOP TH400 short tail trans. I don't like the TH400 gear ratios or changing the yoke and cutting the driveshaft. I seriously considered it, unless I can find a wrecked 70 BBO car for a direct swap drive shaft, probably won't happen. Same reason I am not going 4L80E.
 
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