4r70w replacement

bigbozzo · #1 03-08-2005, 06:28 PM

Hello all,
I find myself about to replace my 4r70w transmision in my 1997 f150. I needed to do this because I cracked the case on my old one due to a CV joint in the driveshaft locking up. My question is when I get a "like" new transmision from a junkyard that my have been sitting idle for some time is there anything special I should do to help asure smouth operation after I install it. I am most concerned about the posablity of it being "gummed" up from sitting (I don't know if or how long it has sat yet). Is there anything else I should be aware of in changing this transmision out? (any updates to make sure I make...)
Thank you
Keith

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dirtyd0g · #2 03-08-2005, 08:13 PM

Save yourself alot of trouble and buy a later model transmission. Anything newer than 97 is a considerably better transmission however 2001 is about the best.
The wiring harness is different so you will need to do one of two things.
1. Change the wiring harness on your vehicle to work with the new trans. This is kindof tricky and quite time consuming until you have done it a few times, but it is the best thing to do for reliability. Here is a good how to,but you will need to get schematics for your vehicle to compare.link
2. Change the wiring harness on the transmission to your older style components, if any contamination or over 60,000 miles on electronics replace them with new.

Be careful of 2003 transmissions as some of them do not have teeth on the output shaft for the vehicle speed sensor.

Match the case with your engine all 5.4 and 4.6 cases bolt up the same and are easily identified by a 3 bolt starter (excluding 92 aod/e units).
3.8,4.2 and 5.0 cases are all the same and have a 2 bolt starter.

Hope that helps and puts you on the right path, nothing is worse than putting in a new transmission that doesn't work correctly.
Sorry I won't be around to help anymore than that for a week or so. I'll be in Vegas

I'll be back on the 26th.
Alan

DDan1967 · #3 01-09-2007, 08:07 PM

There is no need to Replace the wiring harness, all you need to do is rewire one plug on the harness at the transmission end.

Here is a link to a site with instructions.

http://www.tccoa.com/articles/tranny/transmission/page16.shtml

I hope this helps.

Also I agree go with a new transmission if you can.

Doug

dirtyd0g is correct below: I just found out the hard way on my own tranny. I've modified the above link so it show what I originally posted, but it will take you to the page that dirtyd0g mentioned.

dirtyd0g · #4 01-09-2007, 08:28 PM

Do not use the directions on tccoa, they are backwards. Go to modular depot int he thunderbird section there is a sticky by Big Scott, use his directions.
Alan

T Ellenberger · #5 01-10-2007, 01:40 PM

Would there be a problem with the speedo with a newer year transmission? I believe my 97 still has the gear in the rear of the trans for the speedo and the newer transmissions pick up the speed by some electronics.

dirtyd0g · #6 01-10-2007, 03:28 PM

Quote:

Originally Posted by T Ellenberger

Would there be a problem with the speedo with a newer year transmission? I believe my 97 still has the gear in the rear of the trans for the speedo and the newer transmissions pick up the speed by some electronics.

Some vehicles will require changing the tailshaft and or ouptu shaft for those issues. Most however do not.
Alan

DDan1967 · #7 01-10-2007, 08:25 PM

Here is the link to the Website dirtyd0g mentioned that has the correct wiring harness pinout and the change over proceedure.

http://forums.modulardepot.com/showthread.php?t=31261

Doug

dirtyd0g Thank you for correcting me, you've saved me hours of troubleshooting time and I'm sure helped lots of other people too.

Thank you again

Doug

dirtyd0g · #8 01-11-2007, 02:06 PM

You are welcome I try to help when possible, I left the very same link in my original post, just realized this has been almost a year ago, but very very good information.
Alan

DDan1967 · #9 01-13-2007, 01:29 AM

dirtyd0g

I've a question for you, since you seem to be knowledgable in the transmission field.

I installed a '03 4R70W in my '97 and wired it like the tcco site said. Obviously I had Computer Errors and it didn't want to shift and the Engine didn't want to push either.

Well after getting the info you corrected me on. I rewired the connector, no easy task with the transmission installed. Now I have Zero Computer Errors, the Engine wants to run like it should, but the trany won't shift into 2nd Gear.

It will excellerate normally, shift out of 1st then a moment later shift back into 1st. It's like it looks for 2nd and when it can't find 2nd it drops back into 1st.

Neadless to say, this can't be good.

Do you have any ideas? Someone else mentioned the shift cable adjustment, could that be the cause of the problem?

I hope it is something simple and most of all inexpensive, because the rebuilder has already told be they won't honor the warrenty becaue it's the wrong tranny for the truck.

Doug

dirtyd0g · #10 01-13-2007, 02:48 AM

Shift cable adjustment is a possibility but the probability of that being the problem is low. The columns are prone to cracking the shift rod tube. When they do the shifter feels loose. I would double check your wiring. 2nd gear is both solenoids off and failsafe. It sounds to me as if a power wire(probably one of the spares from the old harness) could be on the shift solenoid 1 terminal. Check the mlps adjustment first and if you do not have the updated design unit or have more than 60,000 on it replace the mlps. I get them at ricerzone for $27, or well I make advance match them.