4R70W No Forward Engagement at low rpm's

4R70W No Forward Engagement at low rpm's

Aaron Clark
Aaron Clark

September 19th, 2004, 4:47 am #1

Hi, I have a '95 Thunderbird with the 4R70W automatic tranny. I am experiencing an interesting problem. The transmission will NOT go into any forward gear at low RPM's. When I put the car in drive, the only way that it will engage is if I get the engine RPM's high enough (around 4,000), and then it finally engages (NOT good for the tranny, I know). The car will grab reverse just fine, so I don't think it's a pump problem. Once I get it into gear, all gears pull strong with no slipping whatsoever, but when I come to a stop, it drops out of gear again. It also "neutrals" when doing a hard downshift out of overdrive. Since I have full pulling power in ALL gears once I get the car into drive, I don't think I have any clutch or band problems, but I may be wrong. I re-built this tranny about 40,000 miles ago and upgraded all the hard parts to the latest and greatest stuff, as well as installing a TransGo shift kit, and as long as I can keep it in gear, it shifts awesome. I think I have an accumulator or valve body problem, but I don't know what. I just pulled the pan and re-torqued the valve body to see if that would help, but it didn't. HELP PLEASE!!!!

Aaron
Quote
Share

jeremy
jeremy

August 9th, 2011, 2:08 am #2

I have been searching and searching and have found nothing that explains it!!!

please please please! if you find out can you please email me!!!???

I am hitting walls and ive never been stumped by any trans problem untill this one. help!!!!!
Quote
Share

Joined: November 18th, 2004, 4:20 am

August 9th, 2011, 4:23 am #3

This thread is almost 7 years old.


Number 1 suggestion is fluid level.
Quote
Like
Share

jeremy
jeremy

August 10th, 2011, 1:53 am #4

7 years is a long time, yes, and i was hoping with all that time passed someone could tell me something more than fluid levels. i build A/Ts for fun. though i dont deal with the ELE portion of them and i dont want to drop this one unless absolutly necassary.
Quote
Share

tom
tom

August 11th, 2011, 12:37 am #5

Hi, I have a '95 Thunderbird with the 4R70W automatic tranny. I am experiencing an interesting problem. The transmission will NOT go into any forward gear at low RPM's. When I put the car in drive, the only way that it will engage is if I get the engine RPM's high enough (around 4,000), and then it finally engages (NOT good for the tranny, I know). The car will grab reverse just fine, so I don't think it's a pump problem. Once I get it into gear, all gears pull strong with no slipping whatsoever, but when I come to a stop, it drops out of gear again. It also "neutrals" when doing a hard downshift out of overdrive. Since I have full pulling power in ALL gears once I get the car into drive, I don't think I have any clutch or band problems, but I may be wrong. I re-built this tranny about 40,000 miles ago and upgraded all the hard parts to the latest and greatest stuff, as well as installing a TransGo shift kit, and as long as I can keep it in gear, it shifts awesome. I think I have an accumulator or valve body problem, but I don't know what. I just pulled the pan and re-torqued the valve body to see if that would help, but it didn't. HELP PLEASE!!!!

Aaron
Probable causes 1. low fluid level/cracked filter. 2.worn rings on the stator.3.bad valvebody.
Quote
Share

Joined: August 15th, 2011, 6:23 pm

August 15th, 2011, 6:35 pm #6

Hi, I have a '95 Thunderbird with the 4R70W automatic tranny. I am experiencing an interesting problem. The transmission will NOT go into any forward gear at low RPM's. When I put the car in drive, the only way that it will engage is if I get the engine RPM's high enough (around 4,000), and then it finally engages (NOT good for the tranny, I know). The car will grab reverse just fine, so I don't think it's a pump problem. Once I get it into gear, all gears pull strong with no slipping whatsoever, but when I come to a stop, it drops out of gear again. It also "neutrals" when doing a hard downshift out of overdrive. Since I have full pulling power in ALL gears once I get the car into drive, I don't think I have any clutch or band problems, but I may be wrong. I re-built this tranny about 40,000 miles ago and upgraded all the hard parts to the latest and greatest stuff, as well as installing a TransGo shift kit, and as long as I can keep it in gear, it shifts awesome. I think I have an accumulator or valve body problem, but I don't know what. I just pulled the pan and re-torqued the valve body to see if that would help, but it didn't. HELP PLEASE!!!!

Aaron
many o/hs here at shop as we service all our county sheriff cars past experience has shown me heavy scoring on main regulator valve plus on some vehicles heavy drag wear to one side of valve.valve sticks the increased throttle pressure actually slams valve to allow pressure to engage gear selection.mild polishing could alleviate problem careful not remove to much material as this will decrease pressure.REMEMBER VALVE BORE HAS RELATED SCORING ALSO.have had to replace valve body in severe incidences. about 350.00 bucks. shop around good luck
Quote
Like
Share