To change....or not....?

[BigWhiteFord]

So a transmission tech tested all the electrical systems pertaining to my transmission (4R100 auto) and said everything works as it's supposed to. Transmission shifts normally during a road test. He said the fluid is burnt, but recommended not changing it, as it may mask symptoms or simply be in vain if I need a new transmission anyways.

Do you guys think that the burnt ATF (it's still pinky/red but has a hint of a burned smell) will still provide enough lubricity to not cause further damage, or should I change it? I have a new filter and a bucket of ATF...:confused:

[BigWhiteFord]

Forgot to mention, the Ford got a new starter this week, and boy does it fire up easier than before. It's like a brand new truck, no matter how cold it is.

Old starter was pulling 750 amps on start-up, I believe it's supposed to draw about 300

[TheOtherSide]

All my years of working on weak VW transmissions... I always recommended to the customers to change the ATF and filter before replacing a transmission.... this recommendation was providing there was no major issues with shifting etc... but it's a much cheaper start to the process. Yes, you could be tossing money out the window, but you'll never know if it would have cured the concern unless you try.

ATF is a detergent fluid so if it's been in there for years, you may have some gunk in the system and a fluid/filter change could be just what it needs.... BUT I've also seen it cause more problems as it's cleans up the gunk that's been allowing semi-good shifting.

So, there is no right and wrong decision, but if you have the stuff... do the service and see how it goes. Just my opinion.

Glad to hear it starts up nicely now!!

[Sero]

As long as the ATF your trans takes is regular Mercon/Dexron and not some expensive unique fluid the I agree with Kelly.

Your only going to get a small portion of all the fluid out of the trans by dropping the pan so you will need to do it several times for it to be effective. While you have the pan off you can always install a drain plug if it doesn't have one already so you can do a quick dump and fill.

[BigWhiteFord]

Pan has a plug already. Trans just uses Mercon ATF. Thinking about doing an auxilary external filter as well, when I get some extra money. Possibly swap to the transmission cooler for the 6.0L, as it's supposed to be larger capacity and better design than my 7.3L's tranny cooler.

I guess I'll swap the fluid and filter at work on saturday :headspin:

Thanks boys.

[rothelb]

well how old is the fluid. do you bag on it lots or baby it? my 1 ton gm has a t400 and it was about 12 years old and it was smelling burnt not bad but still did not want probs with new motor built so sent it out to the trany guy that built the trany for the rail and he said it was fine. told him what power i was putting to it and he changed up the cluch packs bands pump and input and output shafts to heavier ones. if there was no more hp added then it would have been fine to run the way it was . so in the short of it if it smells a little burnt and it is old then i would expect it. if not so old i would start looking at the bands....just my 2 cents

[BigWhiteFord]

Update: Transmission is now worse after replacing fluid and filter. It's in full-on limp mode. I get 1st and 2nd gear, no 3rd, no 4th, and no reverse. I phoned around and the general consensus is my 2nd and 3rd gear clutches are toast, and they likely damaged the sprag gears/pin. BC Automatic transmission quoted me $2500 - $3000 to rebuild mine with some upgrades to make it bulletproof. My buddies friends dad owns that shop, so I should be getting a bit of a break on cost.

The plan is for a heavy duty billet dual or triple disc torque converter, 6-pinion steel planetary gear set, upgraded valve body, and might look into getting a tranny cooler from a 6.0L installed as well.

[Sero]

One of previous co-workers is good friends with the owner of BC Automatic, I wouldn't hesitate to go there based on what I've heard.

[BigWhiteFord]

That's what my buddy said. The guy I talked to at the shop said they rebuild hundreds of 4R100's, for armoured cars, big-power diesel drag trucks etc.

[TheOtherSide]

Eeesh... that sucks. Not cheap... and at the perfect time for you too... getting laid off and all.

Ugg....

[BigWhiteFord]

Eeesh... that sucks. Not cheap... and at the perfect time for you too... getting laid off and all.

Ugg....

Very much so, I'm not happy about the timing at all, but not much I can do really. At least it'll be fixed and under warranty. I thought about just picking up a tranny from a wreckers yard, but then I have no idea what it's been through. The last thing I want is to find myself in a situation where I have no reverse out in the woods!

[TheOtherSide]

So what's the update? Trucky getting fixy?

[BigWhiteFord]

I'll be getting it back this week. The internals were just demolished. At least the case wasn't damaged though!

[TheOtherSide]

Good to hear... always nice to be mobile again. But I guess you still have the XJ.