Changing th400 shift points - The 1947 - Present Chevrolet & GMC Truck Message Board Network

75-K5 · 04-28-2004, 01:30 AM

Well we just picked up the "new" '87 stepside with a th400. It has a pretty firm shift kit in it, sometimes gives the tires a little chirp if you give it a lot of gas. My complaint is that it shifts from 2nd to 3rd almost immediately. I would like it to stay in 2nd a little longer. It will stay in 2nd if you keep your foot in it, but not when driving "conservatively." Is there any way to modify when the shift occurs or should I just live with it?

MylilBowTie · 04-28-2004, 02:04 AM

I have noticed that with mine. I thought it needed a rebuild or something(probably still does). How long does second gear stay if you are easy on it?

75-K5 · 04-28-2004, 02:37 AM

I'm pretty sure mine doesn't need a rebuild, it performs great otherwise. When going easy on it, it shifts into 3rd almost immediately after shifing into 2nd. My 76 Monte Carlo did that too, but I got rid of it before I got into tinkering.

MylilBowTie · 04-28-2004, 04:45 AM

I was just speaking for my transmission on the need of a rebuild. I know forsure mine need to be refreshed up. It works fine but it doesn't do things its supposed to do. Someday I will take the governor out to clean and inspect it. That my be the some of my problem right there with the second gear thing. Most all the symptoms Im having deal with 2nd.

I did install a transgo shiftkit. It does hit 2nd pretty good when you are in the gas a little. 2nd is there but its not, sometimes slips, it doesn't help to downshift to 2nd at all, and there isn't any manual braking power in manual 2nd. Also seem that it tries to start out in 2nd gear sometimes, I will notice it bog a little. Put it in manual 1st and it takes off like it should. But I cant really say much, I still need to inspect the governor and install the kickdown switch from lokar.

gldevall · 04-28-2004, 09:39 AM

How long will it stay in 1st under heavy acceleration? Mine will shift about 5300 RPM. But easy driving, it shifts to 3rd pretty quick.

75-K5 · 04-28-2004, 02:00 PM

Honestly, I can't say when it shifts under hard acceleration. I have only driven the truck once last weekend, then I had to head back down to school. I will look more into it when I get home for the summer next week. Is there something I can do with the governor? I know 700r4's have a TV cable you can adjust, do th400's have anything similar?

*rage'nrat638* · 04-28-2004, 06:43 PM

YES TH400 HAS A VERY SMALL SCREW INSIDE THE VACUUM MODULATOR....VIA THE VAC PORT...

*1972C10* · 04-28-2004, 08:06 PM

The modulator will help some but its not going to give you what you want..

I suggest getting a late model 700-R4 govenor and putting it in there You will have to change out the top but its the same other than that the 400 has a tiny nipple rather than the 700s

they sell govenor recalibration kits but its basically doing the same thing the 700r4 has the heavier wieghts and you can generaly get them cheap cheap

Make your choice here is the link for the kit

If you do get a 700 r4 govenor get some finish nails grind out the pins that are holding the govenor cap on and replace it on the 700 govenor and hold it down with finish nails

http://www.jegs.com//cgi-bin/ncommer...97&prmenbr=361

04-28-2004, 01:30 AM	#1
75-K5 Bucket of Bolts Join Date: Dec 2003 Location: Anderson, Indiana Posts: 455	Changing th400 shift points Well we just picked up the "new" '87 stepside with a th400. It has a pretty firm shift kit in it, sometimes gives the tires a little chirp if you give it a lot of gas. My complaint is that it shifts from 2nd to 3rd almost immediately. I would like it to stay in 2nd a little longer. It will stay in 2nd if you keep your foot in it, but not when driving "conservatively." Is there any way to modify when the shift occurs or should I just live with it? __________________ This is the project that never ends, yes it goes on and on my friend....

04-28-2004, 02:04 AM	#2
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	I have noticed that with mine. I thought it needed a rebuild or something(probably still does). How long does second gear stay if you are easy on it? __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

04-28-2004, 02:37 AM	#3
75-K5 Bucket of Bolts Join Date: Dec 2003 Location: Anderson, Indiana Posts: 455	I'm pretty sure mine doesn't need a rebuild, it performs great otherwise. When going easy on it, it shifts into 3rd almost immediately after shifing into 2nd. My 76 Monte Carlo did that too, but I got rid of it before I got into tinkering. __________________ This is the project that never ends, yes it goes on and on my friend....

04-28-2004, 04:45 AM	#4
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	I was just speaking for my transmission on the need of a rebuild. I know forsure mine need to be refreshed up. It works fine but it doesn't do things its supposed to do. Someday I will take the governor out to clean and inspect it. That my be the some of my problem right there with the second gear thing. Most all the symptoms Im having deal with 2nd. I did install a transgo shiftkit. It does hit 2nd pretty good when you are in the gas a little. 2nd is there but its not, sometimes slips, it doesn't help to downshift to 2nd at all, and there isn't any manual braking power in manual 2nd. Also seem that it tries to start out in 2nd gear sometimes, I will notice it bog a little. Put it in manual 1st and it takes off like it should. But I cant really say much, I still need to inspect the governor and install the kickdown switch from lokar. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

04-28-2004, 09:39 AM	#5
gldevall Registered User Join Date: Mar 2003 Location: Walker, LA Posts: 2,925	How long will it stay in 1st under heavy acceleration? Mine will shift about 5300 RPM. But easy driving, it shifts to 3rd pretty quick. __________________ Gary -1986 SWB: lowered 4/6, SOLD!!! -Best 1/4 mile: 14.51 @ 91.01 MPH -2001 Pewter Tahoe, billet grill, Corsa Sport Cat-back, K&N FIPK SOLD!!! -2004 Z-71 Extended cab with a flowmaster, BDS 6.5", 3" BL, 35x12.5x18 Trail Grapplers on Pro-Comp 18x9 wheels

04-28-2004, 02:00 PM	#6
75-K5 Bucket of Bolts Join Date: Dec 2003 Location: Anderson, Indiana Posts: 455	Honestly, I can't say when it shifts under hard acceleration. I have only driven the truck once last weekend, then I had to head back down to school. I will look more into it when I get home for the summer next week. Is there something I can do with the governor? I know 700r4's have a TV cable you can adjust, do th400's have anything similar? __________________ This is the project that never ends, yes it goes on and on my friend....

04-28-2004, 06:43 PM	#7
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	YES TH400 HAS A VERY SMALL SCREW INSIDE THE VACUUM MODULATOR....VIA THE VAC PORT...

04-28-2004, 08:06 PM	#8
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	The modulator will help some but its not going to give you what you want.. I suggest getting a late model 700-R4 govenor and putting it in there You will have to change out the top but its the same other than that the 400 has a tiny nipple rather than the 700s they sell govenor recalibration kits but its basically doing the same thing the 700r4 has the heavier wieghts and you can generaly get them cheap cheap Make your choice here is the link for the kit If you do get a 700 r4 govenor get some finish nails grind out the pins that are holding the govenor cap on and replace it on the 700 govenor and hold it down with finish nails http://www.jegs.com//cgi-bin/ncommer...97&prmenbr=361



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