What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

anyone using th400 low gear planetary?

jp0863

jp0863

1/2 ton status
Joined
Aug 15, 2004
Posts
575
Reaction score
0
Location
clovis, ca
gonna start my complete rebuild (whole truck) and was thinking of dropping in a low gear planetary in the th400 when it gets rebuilt just to get a little more off the line and when offroad. anyone using this and what's your thoughts on it now, was it worth it? thanks.... here's what i'm talking about for those who dont know. http://www.compperformancegroupstor...Screen=PROD&Store_Code=TC&Product_Code=227500
 
odin said:
Its money best spent elsewhere. IMO.
Click to expand...

i would usually agree, however when i do a complete teardown and rebuild of the whole truck, $500 isn't much if it add's to the capabilities of a vehicle... if you've ever towed anything substantial with a 6.2 diesel naturally aspirated, it needs all the help it can get off the line. mine's a turd which is why it's getting a full rebuild with a turbo and everything (maybe even propane)
 
mrdrinksalil said:
what do you mean lowers it even more? It says it doesn't affect final drive ratio. 1to1 i assume. Im confused:confused:
Click to expand...

1st gear, low range... i'm talking about offroad where a lower 1st gear would help which is why i'm looking for someone with experience. what i have read online with other folks who have done this, they love it and wouldnt go back to stock. since none of them are k5's i am asking on here to get an accurate comparison. most of the stuff i have read was from hot rods and rv's
 
I am not 100% positive but the turbo 425 is an extra heavy duty version of the turbo 400. It was used in moving vans ( U Haul ). It had the low gear ratio you wanted. It had strait cut gears ( not helical ) so everybody within 50 ft could hear it shift. Large junk yards may have these transmissions laying around ( for years ). You might pick one up for $100 just to get it out of their yard. I believe they were still used to the late 90's because of their strength and reliability. Please check this information with a reliable transmission shop.
 
There is also a company that makes a 3:1 first gear for the TH400. Basically 700R4 deep with TH400 beef. When I go to a 400 I will most likely put a deeper first gear in.

Dik
 
i'll have to keep my eye's open. the noise is not an issue for me, it's diesel afterall and not exactly quiet.. plus i drive a cummins everyday.
 
The 2.75 planetary would be about the same as going from 4.10 to 4.56 axle gears for crawl ratio when in low range, and the same as 4.10 to 4.37 in high range. The one advantage is would have over axle gears is that you can get a lower low range without affect highway cruising........but in any case it's a really small difference and I really doubt you would notice it much if any.

For all the people who claim they love it......well, maybe so but from what I have seen anybody who drops $500 on something is likely to claim it was a great improvement to justify the expense, they are not going to admit it didn't make much difference.
 
Mike D said:
I am not 100% positive but the turbo 425 is an extra heavy duty version of the turbo 400. It was used in moving vans ( U Haul ). It had the low gear ratio you wanted. It had strait cut gears ( not helical ) so everybody within 50 ft could hear it shift. Large junk yards may have these transmissions laying around ( for years ). You might pick one up for $100 just to get it out of their yard. I believe they were still used to the late 90's because of their strength and reliability. Please check this information with a reliable transmission shop.
Click to expand...



TH475 used straight cut planetaries and a couple of other mods but it kept the same 2.48 ratio.

Gus
 
You must log in or register to reply here.

Latest Posts

Top Bottom