C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

700R4 question

Old 08-10-2018, 05:47 PM
  #1  
Factoid
Le Mans Master

Thread Starter
 
Factoid's Avatar
 
Member Since: Jul 2018
Location: San Antonio, TX/Mahopac, NY
Posts: 8,351
Received 5,516 Likes on 2,782 Posts
2024 Corvette of the Year Finalist - Modified
2024 Corvette of the Year Finalist - Unmodified
2023 C7 of the Year Winner - Modified
Default 700R4 question

I have a C1, but it has a 700R4 behind a 370HP 350 crate engine.

This will sound like a weird question, but should I be able to roll the car around when the engine is off and the tranny is in Drive or Reverse? It rolls just like it is in neutral. In Park the pall engages and it doesn’t move. I’m having a very strange starting problem and I had to push the car back into the garage which is how I discovered it.
Old 08-10-2018, 06:04 PM
  #2  
BowerPower
Advanced
 
BowerPower's Avatar
 
Member Since: Feb 2018
Posts: 86
Received 11 Likes on 11 Posts
Default

That sounds normal to me. If the car stalls will driving, it will coast untill it runs out of momentum. It's not like a manual transmission where it's in gear and turns the engine with the wheels. You theoretically should be able to push it around while it's in drive but I have never tried.

I could be wrong so someone please correct me if I am.
The following users liked this post:
Factoid (08-10-2018)
Old 08-10-2018, 06:16 PM
  #3  
Factoid
Le Mans Master

Thread Starter
 
Factoid's Avatar
 
Member Since: Jul 2018
Location: San Antonio, TX/Mahopac, NY
Posts: 8,351
Received 5,516 Likes on 2,782 Posts
2024 Corvette of the Year Finalist - Modified
2024 Corvette of the Year Finalist - Unmodified
2023 C7 of the Year Winner - Modified
Default

But if you are right, it will be a huge relief!
Old 08-10-2018, 06:33 PM
  #4  
PatternDayTrader
Race Director
 
PatternDayTrader's Avatar
 
Member Since: Oct 2008
Location: Lansing MI
Posts: 17,982
Received 1,056 Likes on 769 Posts

Default

Normal.
The following users liked this post:
Factoid (08-10-2018)
Old 08-10-2018, 07:05 PM
  #5  
Factoid
Le Mans Master

Thread Starter
 
Factoid's Avatar
 
Member Since: Jul 2018
Location: San Antonio, TX/Mahopac, NY
Posts: 8,351
Received 5,516 Likes on 2,782 Posts
2024 Corvette of the Year Finalist - Modified
2024 Corvette of the Year Finalist - Unmodified
2023 C7 of the Year Winner - Modified
Default

Thank you! I was starting to convince myself that the PO had the TV cable screwed up and trashed the tranny.
Old 08-14-2018, 01:54 PM
  #6  
ctmccloskey
Safety Car
Support Corvetteforum!
 
ctmccloskey's Avatar
 
Member Since: May 2001
Location: Fairfax Virginia
Posts: 3,513
Received 1,102 Likes on 874 Posts

Default

I push mine around frequently when working on it. All I hear on my 1988 C4 is the brakes dragging a bit while pushing it. The only squeaks I get are from the suspension when pushing or releasing pressure on the body.
That is a Beautiful Corvette you have there, with the additional horsepower it must be even more fun!

Best regards,
Chris
Old 08-14-2018, 01:58 PM
  #7  
confab
Melting Slicks
 
confab's Avatar
 
Member Since: Nov 2013
Location: Greater Cincinnati Area.
Posts: 3,451
Received 335 Likes on 295 Posts
Default

Agree with everyone.. It's fine.
Old 08-14-2018, 02:19 PM
  #8  
arbee
Melting Slicks
 
arbee's Avatar
 
Member Since: Feb 2003
Location: Saskatoon Sask.
Posts: 2,059
Received 539 Likes on 347 Posts

Default

Originally Posted by ihatebarkingdogs
Normal. Pushing the car backwards, you may hear a "screech" or constant "squeak". This too is normal, in that rolling car backwards causes the lo-roller clutch to slip, and its elements make noise as they slip. There is also more resistance pushing it backwards. Also normal.
Pushing the car backwards causes the low roller clutch to lock up, not slip. The extra pushing effort in reverse movement comes from the rear ring gear spinning the sun gear. This in turn causes the sun shell to spin and by default, the reverse input drum. Pushing the car forward does not cause all this movement because the back planetary is simply walking around the sungear.

Old 08-14-2018, 02:51 PM
  #9  
arbee
Melting Slicks
 
arbee's Avatar
 
Member Since: Feb 2003
Location: Saskatoon Sask.
Posts: 2,059
Received 539 Likes on 347 Posts

Default

Originally Posted by ihatebarkingdogs
What makes the noise then?
Really couldn't tell you but it's not a slipping roller clutch because it is locked. Maybe the clutches in the reverse drum, maybe the spinning sunshell acting on the jaws of the reverse input.

Get notified of new replies

To 700R4 question



Thread Tools
Search this Thread
Quick Reply: 700R4 question



All times are GMT -4. The time now is 06:43 PM.