4R70W, 1st to 2nd==WHIPLASH

[L2rocku2]

Hello all. I have a 2000 explorer, e/b, awd, 5.0, 47k mi, auto, 4r70w
Problem: Shifting from 1st to 2nd is very harsh. The truck lunges forward like someone ran into the back of you. The harder the acceleration, the more severe the shift. It still seems to shift at the right time, meaning, it doesn't hold out for a certain rpm before it shifts. I can take off from a stop, get up to 10-15 mph, and let off the gas and it will still shift into 2nd ( with a small lunge ). This has been going on now for several months. It's my wifes truck, gets driven often but very short trips. No mil light or flashing o/d light. I had the fluid changed, but it made no difference. I do all my own repair work, less machine shop work. I'm no ase machanic, but have been working on cars for 30yrs +-. I've never worked on an automatic transmission before. I've read several of the posts on here, and see that several of you have an enormous amount of knowledge of tranny's. What's causing this?? How to fix it?? Any help is greatly appreciated!!

 

[boominXplorer]

Sounds like something in the valve body is clogged or broken. Hopefully someone else will chime in.

 

[Turdle]

Sounds like something in the valve body is clogged or broken. Hopefully someone else will chime in.

Thanks for saying that--
from what I have learned from our great guru and mentor glacier991
I'd guess the 1-2 accumulator spring--but the solenoid is obviously ok

 

[Glacier991]

I think the best thing to do to start is to check your line and EPC pressures at the taps. If they are ok, either the 1-2 accumulator is stuck or you may have some Valve Body issues. My best assessment absent more. ( I Guess I should offer that if this is the only harshness in any gear, it is not likely a line or EPC pressure issue).

And JT, you have learned well, grasshopper.

 

[L2rocku2]

All other gears work fine. No delay going into reverse or 1st. Shifting is smooth & on time in all other gears.

Why Master Glacier991, why must I walk on the rice paper (LOL)

 

[L2rocku2]

Does anyone else have any ideas? I know many of you have an enormous amount of knowledge of trannys. Without your help & ideas, I'm very leary of taking on this repair. Again, any help would be very appreciated!!!! THANKS!!

 

[L2rocku2]

Mr Glacier991 or JT
Do you have any pictures of the 1-2 accumulator?? When I drop the pan, what will I have to remove to get to it? If anything? Is their anything else that I should check or replace since the pan is off? I plan on getting the new 1-2 accumulator before I drop the pan. Any other parts I should have on hand? You guys are truly masters of the tranny!!! Thanks for all your help!!!

 

[d4rizob]

If you haven't already fixed it, definitely a 1-2 accumulator problem. OEM accumulator is aluminum and the o-rings blow out alot. Get a new steel one from dealer, it is molded with seals. Very easy to change, just need to drop pan and you'll need snap ring pliers. It's next to the VB. Inspect the bore because the old accumulator can damage it,but minor scoring will be ok. good luck

 

[L2rocku2]

Thanks d4rizob !!! I've had a death in the family, but hope to get to the tranny within the next two weeks or so. I'll pick up a steel 1-2 accumulator & a new pan gasket. THANKS again !!!

P.S. How many quarts of tranny fluid will i need to replace??

 

[d4rizob]

You'll need about 5qt's give or take 1. Start with 4 and than check it, don't overfill it. Depending on how old and abused the fluid is, you might want to drain the convertor also. It has a drain plug, just remove the round cover at the bottom of the bell housing and rotate the crank untill you can access it. That will require an extra 5 to 6qts.

 

[L2rocku2]

THANKS to ALL of you who took the time to post and help me out !!!!! Mr jtsmith, you ARE a tranny master !!! It was the lower 1-2 accumulator spring, broke into 3 pieces. I replaced the upper & lower springs (no bore damage at all), 1-2 piston (with steel-THX d4rizob), filter, gasket & 6 qts. mercon v. Shifts like new again !!! THANKS AGAIN 4 all your help !!!!!!!!! YOU ROCK !!!

 

[Glacier991]

Congrats! More and more folks on here are becoming tranny masters as we get past the "voodoo and black magic" that has so long surrounded auto trannies! Nice job JT!

 

[CDW6212R]

Ditto, well done Jon!

 

[Turdle]

ha ha you guys make me blush--when in fact it is Glacier who deserves all of the credit. All I have really done so far is read--

 

[Spdrcer34]

Okay guys, what are the part number for the 1-2 Accumulator Spring, and Piston for the 1998 Mountaineer 4R70W AWD

Thanks,
Ryan

 

[Spdrcer34]

Okay, I found of the part numbers from a write-up online.....

The parts you will need are listed below:

i. F7AZ-7F251-AA Updated Accumulator Piston - Retail Cost $12.00 (Don't use your old one - that is the whole point of this work you are about to do.)

ii. F4AZ-7F247-A 1-2 Cover and Seal - Retail Cost $3.42. This part may be optional if you find a new one already installed. The Cougar had a "new" cover and seal, but an "old" accumulator piston.

iii. F75Z-7F284-AA Upper (Blue) Spring - Retail Cost $3.25. This part is optional. You may be able to use your old spring here. We had one transmission that was completely missing an upper spring (it was in a Cougar.)

iv. F7AZ-7F284-BA Lower (purple) spring - Retail Cost $32.50. This part is optional. As you can see, this is a high cost item. You may be able to use your old spring. One transmission we did in a 94 Mark VIII had this spring broken in two places. There is a picture of these old parts below.

v. Twelve or thirteen quarts of Mercon V or Mercon III - Retail Cost $30.00 to $40.00. We strongly suggest you use the Mercon V. It handles the heat better.

vi. Transmission Filter - Retail Cost $5.00 to 10.00. If you are converting over to Mercon V, replacing the filter is good practice, since you are trying to drain the entire transmission of the old stuff. Auto Zone sells a house brand that comes with a cork gasket. O'Rielly sells a filter that has a neoprene gasket. I prefer the O'Rielly filter to the Auto Zone; simply because of the gasket type makes for easier assembly. Both filters are USA made and seem to be high quality. Make sure the gasket is still in the filter box - sometimes parts houses "borrow" the cover gasket and forget to return the filter to the "missing parts" shelf.

 

[L2rocku2]

Tranny Parts

Okay guys, what are the part number for the 1-2 Accumulator Spring, and Piston for the 1998 Mountaineer 4R70W AWD

Thanks,
Ryan

Hey Ryan
I had a heck of a time trying to find a place to buy tranny parts. I finally came across this place. Every part that I replaced had the exact same part number as the OEM!! I was also shocked at how cheep they sold them!! If memory serves, I think the total $$ for ALL parts & fluid was around 42-47 bucks!!!
The place is called- Transtar Industries, Inc.
They have a toll free # 18008351234 & there local # 6022331446

The guy that helped me really knew his stuff!! And was very friendly Actually, when I told him the make & model, and what I needed, he didn't even look in a book, just went down the rows of shelves and pick them out. It's a huge building and I'm pretty sure that he told me that they could build any tranny (100% complete) from parts. They also stocked the parts if you wanted to modify the tranny.
Hope this helps!!

 

[Spdrcer34]

Thanks!

I found this write-up online last night....it was after after 1am, and EF shut down...so I searched elsewhere...

http://www.markviii.org/LOD2/1_2_Accumulator_paper.htm

That is a whole write-up, complete with part numbers. I was able to to buy them last night (this morning?) I got the spring, piston, and cover for $25.xx shipped.

This was the CHEAPEST place I could find anything...

http://www.transmissionpartsusa.com/AODE_4R70W_4R75W_Transmission_parts_s/1930.htm

 

[shipwreck17]

Damn I saw this too late... I was going to bet on the spring.

I used to have a Mark VIII