questions about 4r70w

Spaceman Spiff · #1 02-10-2003, 09:00 AM

hi, i'm new to the auto tranny scene, and i have a couple of questions. first, when i put the truck in drive, i have to really hold down the brake pedal or it kinda "jumps". this is usually after i first start it up after sitting for a while. i suppose it could be that it is still warming up and the rpms are too high?
second question. how long should it take to go into gear, either drive or reverse or whatever? i back into the space i use at work, and when i go from drive to reverse there is about a 1 or 2 second delay. i can push the gas and the truck will start rolling backward, but then i will feel it actually go into reverse after it is already moving. is this normal? thank you all for your input.

suvdrvr · #2 02-10-2003, 08:18 PM

Sounds pretty normal to me, If your fluid level is good.
The colder out it is the longer it takes to engage in gear. After you have warmed up the engage should be pretty quick. And when your engine is cold it will fast idle producing a jump when you put it in gear.

SSCULLY · #3 02-10-2003, 11:49 PM

Spaceman Spiff,

On the second issue, there is a TSB that sounds similar to what you are having happen.

Issued 11-JUN-01, article 01-11-7.

It notes that some 4R70 trans exhibit a no forward or a delayed engagement may have a damaged forward clutch.

The fix is a PCM upgrade and a forward clutch repair.

The one thing to note is this is listed as for 2001 year trucks, I don't know what year you have to confirm this.

It noted in the TSB that this might be caused by rapid shifting from D to R without the trans fluid reaches normal operating temp and by PCM calibration causing a lack of forward clutch pressure and insufficent lubrication.

This is listed for 2001 model years, so keep that in mind when comparing this to your problem description as I read it.

Good luck with it.

Steve

B-Man · #4 02-11-2003, 11:37 AM

Spaceman Spiff -

Definitely follow sscully's advice regarding the TSB. If that isn't the issue, I offer the following:

My truck was slow to go into reverse at any operating temperature.

After I installed the TransGo S/K, it behaves as you would expect an automatic to, except it's more better!

Spaceman Spiff · #5 02-11-2003, 03:58 PM

mine is an '02, but i will see if there is anything on it at the dealership.
B-Man:
that is definitely on my list of things to do! how hard is the install on one of those? i am waiting to make sure these items are normal so i dont void my tranny warranty because of the s/k.

SSCULLY:
what kind of PCM upgrade? i am just wondering if it would screw up any plans of having a superchip in the future....

thanks for all your replys!!

SSCULLY · #6 02-11-2003, 05:34 PM

Quote:

Originally posted by Spaceman Spiff
what kind of PCM upgrade? i am just wondering if it would screw up any plans of having a superchip in the future....

They reflash the code on the PCM, just make sure to tell the dealer to mark the new verson of the code on the sticker when they put it under the hood.
The dealer is to be doing this, but I have seen where they don't do it.
For the TSB, once fixed, an update sticker is to be put under the hood by the belt diagram info.

If you are getting a Chip then you will need this info when ordering the chip, if you are getting a mircotuner programmer, then it won't matter.
If the code is not on the tuner, the tuner will pull the info needed, and give a code that says to sent it back to have the code updated to run with the PCM code they put on it.

B-Man · #7 02-11-2003, 07:48 PM

Spaceman -

I wrote up my install of the TransGo S/K:

TransGo S/K Installation

Definitely one of the best mods I've done so far...

Be sure to talk to Mike T. before you buy anything. The chip's program is dependant on many of the mods everyone likes to do here...