Solved 97 Mountaineer V8 AWD Transmission holding shifts btw 1-2

[mf7365]

If I let off the gas it shifts right into 2nd gear. Otherwise it holds 1st gear up to around 4,000rpm. Otherwise everything is shifting smooth as ever. Ive heard it could just be a loose vacuum line to a modulator valve and also that the transmission is electronic and there is no modulator valve. If it is a modulator related issue where is located?

 

[Cpl. Opey]

Have you checked the transmission filter, or had the tranny serviced recently?

 

[mf7365]

Yes, I had the transmission fluid flushed and replaced about 40,000 miles ago. Its been done on schedule throughout its life. Always full synthetic. I've never had a single issue with the transmission up to yesterday when it started doing this.

 

[C420sailor]

Could be a sticking accumulator or broken accumulator spring. Both easy fixes once you drop the pan.

My 2-3 shift would hang like that, although not as severely. It was a 2-3 accumulator with dried out seals that was hanging up in the bore.

 

[mic98xlt]

Many years ago my wife's 97 Mountaineer with a 5.0 v8 had the exact same problem. It would hold on from shifting 2-3. It was the accumulator like C420 stated and a updated part in valve body corrected it. There is a old TSB about it that I found somewhere here on this forum.

 

[mf7365]

So how do I know if I have the 4R70W transmission or the 5R55E ?

 

[mic98xlt]

So how do I know if I have the 4R70W transmission or the 5R55E ?

The 5.0 V8 has the 4R70W.

 

[mf7365]

So it looks most likely to be a broken spring or sticking accumulator piston. Also looks like the valve body doesnt need to come off for the 1-2 shifter accumulator repair. I'm going to order the new springs and piston and also a new oil pan gasket and filter. Doesn't look too difficult. If I'm just dropping the pan I shouldn't need to do a complete tranny refill correct? Maybe 5 quarts replaced?

 

[C420sailor]

5-ish. It’s a very simple job.

You’ll want either a big c-clamp or a bottle jack to press the accumulator up in the bore—and snap ring pliers to remove/install the ring. The springs are pretty stout.

While you’re in there, may as well change the filter, remove the pan magnet and clean it off. Also a good time to install a drain bolt if you’d like.

 

[96eb96]

5-ish. It’s a very simple job.

You’ll want either a big c-clamp or a bottle jack to press the accumulator up in the bore—and snap ring pliers to remove/install the ring. The springs are pretty stout.

While you’re in there, may as well change the filter, remove the pan magnet and clean it off. Also a good time to install a drain bolt if you’d like.

:lol: Like 20 years ago, this was an everyday problem on T-bird and Mk8 forums. Plenty of info around.

 

[mf7365]

Hopefully this solves the problem. I've got 271,000 miles on the tranny and engine. I've owned it from day 1. This is the first tranny problem I've had. I rebuilt the transfer case and replaced the timing chain at 130,000. I've got an oil leak that's been steady from the oil pan gasket, but its such a major PITA to deal with I just add a quart whenever necessary.

 

[crunchie_frog]

Keep us posted... I have replaced two of the 1-2 springs and that fixed irregular shifts between 1 and 2. Both springs were broken. Could be the accumulator seal as well, hopefully just a broken spring. I am hoping your effort does repair the problem and if it does, it is a good example of how this forum can save users a lot of money. If it works, you will have spent <$50 for a repair that actually fixes the problem vs thousands of dollars for a repair by a shop or dealer that may or may not fix the problem.

 

[C420sailor]

Yep. Lots of shady places would say ‘oh you need a rebuild’

 

[mf7365]

Sorry it took so long to get back. The parts came in last tuesday but had to wait until this weekend to get started. Sure enough. the inner, smaller spring in the 1-2 accumulator was in 4 pieces. I had purchased both springs and a new cylinder and cover. Put everything back together with a new filter and 5 quarts of fluid and it shifts like brand new. The magnet in the pan only had the expected accumulation of very fine particles, almost like a sludge. Nothing you could actual pick out. So far so good.

 

[C420sailor]

Nice!!!