TH400 Help!! High RPM problem
Thread Starter
4th Gear
Joined: May 2008
Posts: 4
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From: Kristiansund
TH400 Help!! High RPM problem
I have a 75 mod with a 350 cid. TH400 transmission. and a 3.08 rear axle ration.
The problem is that I have 3700 RPM at 50 Mph. ( With sidepipes this makes a lot of noise)
The transmission gears from 1 to 2 of 20 Mph and from 2 to 3 at 33 Mph.
When I gear from 2 to 3 the RPM drops with 700 RPM.
The transmission was originally from a Chevy diesel truck / van.
The TH 400 should have a 1-1 ratio at 3rd gear.
My rear wheels are 64 cm in diameter.
If everything was working as it should I should have 2100 RPM at 50 Mph.
Could someone give me some tips?
The problem is that I have 3700 RPM at 50 Mph. ( With sidepipes this makes a lot of noise)
The transmission gears from 1 to 2 of 20 Mph and from 2 to 3 at 33 Mph.
When I gear from 2 to 3 the RPM drops with 700 RPM.
The transmission was originally from a Chevy diesel truck / van.
The TH 400 should have a 1-1 ratio at 3rd gear.
My rear wheels are 64 cm in diameter.
If everything was working as it should I should have 2100 RPM at 50 Mph.
Could someone give me some tips?
