Road_Case
Member
Hey everyone. Pearl is starting to act up lately!
There seems to be a F***ton of trans issues/questions threads on this site. So I'll make mine short and sweet.
'90 8-lug K2500. Odometer reads 146,XXX. 5.7/TH400/floor-shift-TC(NP241?). 14-Bolt semi-float, 3.73, G80-optioned. I think that covers drivetrain. Now symptoms.
First thing was slow to engage reverse. Problem worsened gradually, rectified in-the-moment by increasing engine RPMs. Results in reverse engaging after a light jerk rearward. Problem has worsened very slightly over time and is still present.
Recently developed problem is 2-3 shift/slip while cold (like, sitting overnight cold). 1-2 shift while cold is normal, usually around 10mph vehicle speed. 2-3 shift NORMALLY occurs/occurred roughly around 40mph prior to abnormal operation.
Lately, once that 40mph-ish mark is reached, I'm feeding her 1/8-to-1/4 throttle, she continues revving up very high in 2nd, forward pull seems to plataeu and will not complete the shift to 3rd. Once I let off throttle, shift to 3rd occurs. Once I give it anything more than 1/8 throttle, seemingly, transmission sort of slips back into 2nd and revs real high with very little pull feeling in the seat of my pants. Just a big noise-maker lol.
After 10-15 minutes of driving this all goes away and transmission shifts normal and tight.
No lights on dash on account of these shift points being vacuum-modulated.
Open to all suggestions, including any information available concerning what's needed for swapping to a 4l80e from a TH400. I hope I made this easy to read.
I have an alldataDIY subscription for this truck, just to throw that out there. Thanks!
EDIT: I just want to add that reverse gear engagement does NOT improve with a warmed up drivetrain.
There seems to be a F***ton of trans issues/questions threads on this site. So I'll make mine short and sweet.
'90 8-lug K2500. Odometer reads 146,XXX. 5.7/TH400/floor-shift-TC(NP241?). 14-Bolt semi-float, 3.73, G80-optioned. I think that covers drivetrain. Now symptoms.
First thing was slow to engage reverse. Problem worsened gradually, rectified in-the-moment by increasing engine RPMs. Results in reverse engaging after a light jerk rearward. Problem has worsened very slightly over time and is still present.
Recently developed problem is 2-3 shift/slip while cold (like, sitting overnight cold). 1-2 shift while cold is normal, usually around 10mph vehicle speed. 2-3 shift NORMALLY occurs/occurred roughly around 40mph prior to abnormal operation.
Lately, once that 40mph-ish mark is reached, I'm feeding her 1/8-to-1/4 throttle, she continues revving up very high in 2nd, forward pull seems to plataeu and will not complete the shift to 3rd. Once I let off throttle, shift to 3rd occurs. Once I give it anything more than 1/8 throttle, seemingly, transmission sort of slips back into 2nd and revs real high with very little pull feeling in the seat of my pants. Just a big noise-maker lol.
After 10-15 minutes of driving this all goes away and transmission shifts normal and tight.
No lights on dash on account of these shift points being vacuum-modulated.
Open to all suggestions, including any information available concerning what's needed for swapping to a 4l80e from a TH400. I hope I made this easy to read.
I have an alldataDIY subscription for this truck, just to throw that out there. Thanks!
EDIT: I just want to add that reverse gear engagement does NOT improve with a warmed up drivetrain.
Last edited: