Trans question - Moparts Forums

Register Log In Moparts Forums Unlawfl's Race & Engine Tech Trans question

Print Thread

Trans question #1649819 07/22/14 06:58 PM 07/22/14 06:58 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Can something in the trans cause 14% slippage? Turning 6000 rpm in the eighth at 98 mph. Thought convertor was bad, so I put in a new one. Still the same. According to Wallace calculator, I should only be turning about 5200 Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649820 07/22/14 07:29 PM 07/22/14 07:29 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	Accuracy of the tachometer? R.

Re: Trans question [Re: dogdays] #1649821 07/22/14 07:35 PM 07/22/14 07:35 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Brand new AutoMeter playback tach Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649822 07/23/14 12:19 AM 07/23/14 12:19 AM
Joined: Nov 2004 Posts: 1,760 Port Alberni, British Columbia MoparDonny top fuel
MoparDonny top fuel Joined: Nov 2004 Posts: 1,760 Port Alberni, British Columbia	If it's the trans it will tell you sooner than later.

Re: Trans question [Re: racerb440] #1649823 07/23/14 02:05 AM 07/23/14 02:05 AM
Joined: Aug 2003 Posts: 43,118 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,118 Bend,OR USA	Quote: Can something in the trans cause 14% slippage? Turning 6000 rpm in the eighth at 98 mph. Thought convertor was bad, so I put in a new one. Still the same. According to Wallace calculator, I should only be turning about 5200 Measure the circumference of YOUR rear tires and then do the math on how many feet per minute your running at the finish line If your running bias ply tires you might want to add 1 to 2.5 % to the circumference for tire growth If radial tires don't add anything more to the actual circumference Let us know what you find, tach errors and crummng converters can drive you absolutely NUTS Good luck Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Trans question [Re: racerb440] #1649824 07/23/14 02:19 AM 07/23/14 02:19 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Are you running a RMVB or a standard VB.. if standard you could have real low line pressure

Re: Trans question [Re: MR_P_BODY] #1649825 07/23/14 07:53 AM 07/23/14 07:53 AM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	It's a RMVB. What causes low line pressure? I don't know much about auto transmissions. Could bad clutches do this? Trans is only two years old. Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649826 07/23/14 09:36 AM 07/23/14 09:36 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: It's a RMVB. What causes low line pressure? I don't know much about auto transmissions. Could bad clutches do this? Trans is only two years old. Being a RMVB your pressure is preset in the VB.. I forget if you would have a throttle pressure on that.. I know the trans brake you dont get throttle pressure and its locked... but I have the trans out of my Rampage and between a bad shifter cable adjustment and low throttle pressure it FRIED the low clutch(all the fiber was gone)and it slipped

Re: Trans question [Re: racerb440] #1649827 07/23/14 05:05 PM 07/23/14 05:05 PM
Joined: Jan 2003 Posts: 25,747 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,747 Rio Linda, CA	Quote: Could bad clutches do this? Trans is only two years old. Yes. Only way to know for sure is to disassemble. How is your 2-3 shift? Firm, slips into gear a little? The INTERNET, the MISinformation superhighway

Re: Trans question [Re: John_Kunkel] #1649828 07/23/14 05:20 PM 07/23/14 05:20 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Seems to shift firm, however on both 1-2 and 2-3 rpm only drops about 500 rpm or so and that doesn't seem right Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649829 07/24/14 10:35 PM 07/24/14 10:35 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Just checked line pressure. Read 115 psi 3rd gear 2000rpm. Is this too low for a RMVB? Could this cause the clutches to slip? Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649830 07/24/14 11:09 PM 07/24/14 11:09 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Just checked line pressure. Read 115 psi 3rd gear 2000rpm. Is this too low for a RMVB? Could this cause the clutches to slip? Maybe one of the trans guys will answer this .. but I run 180 to 190

Re: Trans question [Re: MR_P_BODY] #1649831 07/24/14 11:27 PM 07/24/14 11:27 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Thank you. I'd ask my trans man, but I think I made him mad when I said there might be a problem with his trans. Can't seem to be able to get ahold of him now. Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649832 07/25/14 02:50 PM 07/25/14 02:50 PM
Joined: Jan 2003 Posts: 25,747 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,747 Rio Linda, CA	You have to know what VB you have and what its line pressure is supposed to be. Where are you measuring the line pressure? The INTERNET, the MISinformation superhighway

Re: Trans question [Re: John_Kunkel] #1649833 07/25/14 03:29 PM 07/25/14 03:29 PM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Measuring it at line pressure outlet on right side. Trans man says it should be about 160 psi. Not sure of brand, but it is a reverse pattern manual w/ low band apply. Just wondering if low pressure could cause 14% slippage. Car launches good, but slips all the way down the track. Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Re: Trans question [Re: racerb440] #1649834 07/26/14 12:06 AM 07/26/14 12:06 AM
Joined: Aug 2003 Posts: 43,118 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,118 Bend,OR USA	Quote: Measuring it at line pressure outlet on right side. Trans man says it should be about 160 psi. Not sure of brand, but it is a reverse pattern manual w/ low band apply. Just wondering if low pressure could cause 14% slippage. Car launches good, but slips all the way down the track. The first custom built 8 inch race converter I bought and used in a "race car" was a Art Carr, it broke during the second run Bottom line was it was to loose, it would slow the car down .034 to .041 in ET and 3 to 4 MPH in the 1/4 mile over the stock 11 inch street hemi converter It would revved like crazy at the hit of the throttle, go to 6000 RPM and stay there for a while in 1st gear and then accelerate up to 7000 RPM on the shift points, it would drop back to 6000 RPM and lay there again for awhile before strting to gain RPM, it was a real turd My message is your converter may be no good like that one I've since had two more bad 8 inch converters like that, one TCI and one GER I've also had several very good converters from A-1, B&M, Rossi, Continental, Turbo Action and several other good comapnys. Buy the best race converter you can find Not the cheaper ones Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Trans question [Re: racerb440] #1649835 07/26/14 07:33 PM 07/26/14 07:33 PM
Joined: Aug 2003 Posts: 136 Dallas, TX 4 440Brian member
440Brian member 4 Joined: Aug 2003 Posts: 136 Dallas, TX	My converter slippage decreases during the run. It's much lower after a 1/4 mile than an 1/8th. Mine is about twice that at that point on a run, but I'm measuring it using engine rpm/driveshaft rpm.

Re: Trans question [Re: 440Brian] #1649836 07/26/14 07:43 PM 07/26/14 07:43 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: My converter slippage decreases during the run. It's much lower after a 1/4 mile than an 1/8th. Mine is about twice that at that point on a run, but I'm measuring it using engine rpm/driveshaft rpm. A 1/4 mile run has a lot more of pulling rpm than a 1/8 mile run and will show a lesser/better slippage rate

Re: Trans question [Re: MR_P_BODY] #1649837 07/27/14 03:03 AM 07/27/14 03:03 AM
Joined: Jul 2005 Posts: 62 Kingston, OK R racerb440 OP member
racerb440 OP member R Joined: Jul 2005 Posts: 62 Kingston, OK	Well, Kenny at PTC convinced me that both my converters which were built to run at 6000' above sea level are going to be way too loose down here at almost sea level, so I've got a new 8 inch race unit on the way. Thanks for all the help, everybody. Bob - 67 Dodge Coronet 11.35,116.95 at 5880'

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1