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727 MVB trans slipping in first

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383 w/ 727 manual valve body. I’m new to the MVB. When I’m shifting through the gears while accelerating, everything is fairly smooth. However, if I accelerate in first, let off the gas a bit, and then accelerate again (staying in first) it feels like it’s slipping? Is this normal, or do I have a problem?
 
There are a lot of different MVB's out there.... always a good idea to pose your questions to the maker.
A couple things to check....basics...you 100% sure fluid level is correct? Linkage putting the lever at the trans solidly in the detent at low gear?, and low/reverse band tightened to spec??
 
There are a lot of different MVB's out there.... always a good idea to pose your questions to the maker.
A couple things to check....basics...you 100% sure fluid level is correct? Linkage putting the lever at the trans solidly in the detent at low gear?, and low/reverse band tightened to spec??
There are a lot of different MVB's out there.... always a good idea to pose your questions to the maker.
A couple things to check....basics...you 100% sure fluid level is correct? Linkage putting the lever at the trans solidly in the detent at low gear?, and low/reverse band tightened to spec??
I should clarify that it is a reverse manual valve body. The maker?
 
DO NOT let off the gas and add throttle driving a rev manual valve body that coasts when you release the throttle. You are hitting the the low roller clutch. Disaster will follow. Best advise is use 1st only to accelerate. Never coast. Shift to 2nd if slowing down. Use 1st only from a dead stop. No burnouts in 1st either. If the low roller clutch fails the forward drum will speed to aprox 2.3 times engine rpm. Anything much over 10,000 rpm for a stock drum is no mans land. That means anything over about 4400 engine rpm with a low roller failure and you could have a bomb.
Doug
 
DO NOT let off the gas and add throttle driving a rev manual valve body that coasts when you release the throttle. You are hitting the the low roller clutch. Disaster will follow. Best advise is use 1st only to accelerate. Never coast. Shift to 2nd if slowing down. Use 1st only from a dead stop. No burnouts in 1st either. If the low roller clutch fails the forward drum will speed to aprox 2.3 times engine rpm. Anything much over 10,000 rpm for a stock drum is no mans land. That means anything over about 4400 engine rpm with a low roller failure and you could have a bomb.
Doug
Thanks so much for the education Doug. You probably just saved me thousands!$! MUCH appreciated!!
 
Double check the linkage adjustment too. Just in case. dvw is right on, with most RVM valve bodies you don't lift in 1. Always be in 2 OR 3 to lift.
 
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The maker?
You really should know who manufactured the body, and you should get the instructions that come with it....many come with specific words of wisdom, such as the instructions Doug just gave you.
 
Manual 1st gear engages the low/rev band. It could be worn or needs adjusting.
 
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