5R55 upshifting too quick?

[Green98XLT]

Hey guys, I've been doing alot of work to get my 99 SOHC running better in order to tow my wifes little horse trailer around some this summer. I just put new plugs/wires in as well as cleaned the MAF and installed a MAF adaptor and K&N conical filter. The motor seems to run great and no real problems with the transmission either but I have noticed that it seems to upshift waaay to soon. It's in 5th gear by 45mph and it doesn't want to downshift when needed unless you stomp the pedal. Is this a normal characteristic of the 5R55? It will lug down to 1200rpm or so before downshifting, and it never wants to come out of OD. I know the larger tires may be affecting this somewhat but they are only 31's..

At first I was thinking the motor was at fault but the more I drive it now I really think its just the trans keeping the motor out of its powerband. I just ordered the Transgo shift improver kit, will this help? It just started with the 3-4 shift flare so I know it is needed.

 

[IZwack]

I'm not sure about the change in shift points but the 31" tires are definitely offsetting your speed sensors. So 45 mph is really about 48mph.

Personally, if you are going to use this Explorer to pull, I would stick with the stock tire dimensions as larger tires will only rob your vehicle of torque.

 

[Glacier991]

How many miles? I'd seriously consider replacing the EPC if you have many miles, and maybe doing the 5R55E valve body rebuild. This unit does not like to tow in overdrive unless it's downhill, or flat (preferably with the wind at your back.) ALso adding the biggest transmission fluid cooler you can get is also a good idea. Some folks put a separate fan on the cooler.

 

[BrooklynBay]

A remote filter is also a good idea with a transmission temperature gauge.

 

[Glacier991]

With all due deference, for longevity, the external filter is way down my list. Nice to have ? Sure. But as for making your trans last longer.... esp if you take good care of it, eh. Do the other things first.

 

[Green98XLT]

Well... it has 120k miles on her but it's in prestine shape, 1 owner and serviced every 30k miles (trans) at the dealer. This was one of the main reasons for buying it with that kinda mileage. Never used for towing and mostly all highway mileage (knew the guy that traded it in)

Anyway, I never tow in OD, and I'm getting ready to do the VB rebuild per your excellent diary Glacier. I just got the Transgo kit (please see my other post on this) but I am having problems finding the correct seperator plate gaskets for my trans.... I seem to have no luck on the ford parts network site at all...

I can't believe they sell you a shift kit but don't include the darn required gaskets! That amazed me but from what I can tell none of them do but Ford..

 

[Glacier991]

The separator plate for yours is listed in the TSB, in the first page of the diary as being part no:

1L5Z-7Z490-GA

and it should have bonded gaskets. It is an upgrade, and also probably why you are having trouble finding gaskets separately. As I said in the Diary, If you go the FORD mod route the transgo kit I had was largely duplicative of the FORD mods, and I recommended Superor + FORD TSB modifications. (Once again adding I a HUGE fan of Transgo's products).

 

[Green98XLT]

Thanks glacier. I called my buddy at the Ford parts counter yesterday and he claims he has both in stock there for me so we'll see...

I already have the Transgo kit so I see no reason to get the ford TSB kit now, I've always liked Transgo stuff in my mustangs and other vehicles so I don't think I'll go wrong.

I plan to use a light spray adhesive to bond the gaskets to my seperator plate, see anything wrong with this idea?

 

[Glacier991]

If you stay with the Transgo kit stay with your original separator plate and add the Transgo rivet. You'll need stock gaskets for it. (You probably already knew the above).

As for DIY bonding of gaskets... the thought had crossed my mind, but I dismissed it as something I'd let someone else try. I have an uneasy feeling about it I cannot explain.

I again suggest you replace the EPC.

 

[Green98XLT]

Thats the plan. I'm keeping my separator plate and just buying the gaskets. I'm also going to check out the solenoid bracket real well. I may replace it too but my dealer had to order it.

I'm still up in the air on the bonding of my gaskets... I don't see why it would be different than what ford does but who knows..

I'm going to try to replace the EPC but I can't have the truck down more than the weekend and everyone around here has to order it. I guess I can go back in anytime and replace it if it is bad... the truck runs perfect though so I'm really just being preventive here.