Need a concise summary of pros vs cons on tranny **UPDATE**

Pote · **Posted:** Thu Jun 12, 2008 1:38 pm

So I have an appointment to have my tranny fluid replaced this weekend when I do my rotations and oil change. The tech and I were talking and I wanted him to drop the tranny pan to do the fluid replacement. He insists that the way they do their flushes is better than simply dropping the pan and replacing the fluid. I asked him why and he went over the fact that a flush will be more encompassing and actually gets all the bad stuff out of the transmission rather than just getting new fluid and filter in the pan.

Can you guys tell me the pros and cons of both? a flush vs a pan drop and refill? I've read some of the horror stories about flushing but would like to get some info in a single paragraph of what those pros vs cons are. I totally trust this shop, but was surprised they want to push the flush over dropping the pan...he said they would drop the pan after they've done 2 flushes...basically the third time they will drop it and replace the filters too...what do you guys think? let them do the flush and fill, or demand they drop the pan and go that route?? please give me some good arguments in favor of either, or give me the bad points of why I shouldn't do a flush....thanks in advance...Saturday is D-day. LOL

tjkj2002 · **Posted:** Thu Jun 12, 2008 1:46 pm

How many miles are on your KJ?

That's the biggest ?,if you are over 50,000 miles I highly DO NOT recommend a tranny flush.A tranny flush(with the correct machine and chemicals)will clean all the sludge and bad fluid in/out of the tranny,on higher mileage trannies that sludge is actually preventing seal leaks and taking up the clearences in the valve body.If that sludge is removed you run the risk of having leaky seals and/or a tranny that doesn't shift right and fail shortly after.

I'm all for tranny flushes but they need to be done early and often,every 30,000 miles at least.I have my tranny flushed every 15,000miles and every 30,000miles I also have the filters changed.A flush is better since it removes and replaces all the fluid,not just a 1/3 of the fluid like a drain/refill does.

sleeve84028 · **Posted:** Thu Jun 12, 2008 1:51 pm

I say the same thing:

Flush every 30K miles and be regular about it. Otherwise, changing the fluid will lead to the loss of your transmission for the reasons listed.

My schedule is:

30K; flush

60K: flush + filter change

90K: flush

120K: flush + filters...

Currently I'm only at 70K so I can't really give you a reliability report on my proceedures. I should say that I tow often and my transmission still works like a top.

Cowpie1 · **Posted:** Thu Jun 12, 2008 10:19 pm

I'll have to agree with the responses here. Trannies are often overlooked but the ideal is a transmission service on a regular basis.

I take it a step further. I get a complete flush and replace filters every 30K miles. I also use a high quality synthetic brand ATF. I have a CRD with the 545RFE tranny, so to do a filter change there is no choice but to drop the pan. So you could say I get a complete fluid flush and a pan drop each time.

Some would argue that this is a waste to do the tranny so often. But they also have no problem spending money on cosmetic items, lifts, big tires, etc. Regular transmission service is vital to getting long life out of a transmission.

Unless you are considering doing it yourself, I would look for a shop that specializes ONLY in transmissions. Not the general repair shops or the speedy lube places. The prices are usually reasonable and the service people at transmission only shops are a little more concientious about doing the job right the first time. Also, they are quick to spot a potential problem with a transmission sooner. I am fortunate that I have a local shop that specializes only in auto transmissions and there is only the owner and another tech at the place. They have a solid reputation in the area and they are quick to back up their work. Check around for such a place and stick with them. You will be glad you did. Just my .02 worth.

tjkj2002 · **Posted:** Thu Jun 12, 2008 11:26 pm

Cowpie1 wrote:

I'll have to agree with the responses here. Trannies are often overlooked but the ideal is a transmission service on a regular basis.

I take it a step further. I get a complete flush and replace filters every 30K miles. I also use a high quality synthetic brand ATF. I have a CRD with the 545RFE tranny, so to do a filter change there is no choice but to drop the pan. So you could say I get a complete fluid flush and a pan drop each time.

Some would argue that this is a waste to do the tranny so often. But they also have no problem spending money on cosmetic items, lifts, big tires, etc. Regular transmission service is vital to getting long life out of a transmission.

Unless you are considering doing it yourself, I would look for a shop that specializes ONLY in transmissions. Not the general repair shops or the speedy lube places. The prices are usually reasonable and the service people at transmission only shops are a little more concientious about doing the job right the first time. Also, they are quick to spot a potential problem with a transmission sooner. I am fortunate that I have a local shop that specializes only in auto transmissions and there is only the owner and another tech at the place. They have a solid reputation in the area and they are quick to back up their work. Check around for such a place and stick with them. You will be glad you did. Just my .02 worth.

X2.......

I take my KJ to a dealership for my tranny flushes/filter changes so if it screws up it's covered.Yes I pay a little more but at least the correct parts and fluid get's put in.All the dealers that have worked on my KJ have been very excited about my KJ and have always taken care of me.The Jeep dealer I go to here in CO charges $140 for the tranny flush,and a extra $80 for the filters to be changed,not bad since ATF+4 is a little more pricey and they do the tranny quick re-learn for free also.There waiting to see my SFA conversion,there just as excited about it as I am.

Pote · **Posted:** Fri Jun 13, 2008 11:10 am

. sorry I double tapped the post.

Pote · **Posted:** Fri Jun 13, 2008 11:10 am

thanks for the responses so far guys. to answer a few questions.

I currently am at 75K miles. I am the second owner of this 2003 leased vehicle (original owner leased). QUESTION on that: When a customer enters a lease with a dealership, is it pretty mandatory that the dealership REQUIRES the customer follow scheduled maintenance or do they leave it up to the customer??

I have no way of knowing if the original owners did all the maintenance at regular intervals. I bought the KJ with about 48K miles. So being at 75K, you guys recommend just dropping the pan and avoiding the flush entirely since I don't know if they followed the 30K mile change. I also blew by the 60K maintenance, hence the reason I'm itching to get this done....next oil change I'm doing the diffs too.

Any other advice, so far I'm seeing just drop the pan and refill...right?!?

mrkake · **Posted:** Fri Jun 13, 2008 11:37 pm

I have the same question as Pote. I am approaching 50k miles. I did a quick drain and refill about 12k miles ago. I could drop the pan and change the filters myself right? If it's a flush that's in order, there's a dealership about 3 miles away that just opened a little while ago. I have been meaning to drop in and take a look at their service center. Maybe this is a good reason to introduce myself.

InCommando · **Posted:** Fri Jun 13, 2008 11:49 pm

My wife wants new vehicles, so she leases something every 2 years. Although the contract says that we will perfrom all required maintenece per the schedule, not once have we been asked about it or had to prove it on turn-in. So, I'd worry about a lease turn in being serviced regularly even though I do service hers on time.

I also have only anecdotal evidence that flushing a high-mileage tranny will cause it to screw up, but I have heard of this happening. I would not do a flush for the first time on a high-mileage tranny: Drop the pan & drain the fluid, replace the filter, & call it good.

Pote · **Posted:** Tue Jun 17, 2008 11:08 am

InCommando wrote:

My wife wants new vehicles, so she leases something every 2 years. Although the contract says that we will perfrom all required maintenece per the schedule, not once have we been asked about it or had to prove it on turn-in. So, I'd worry about a lease turn in being serviced regularly even though I do service hers on time.

I also have only anecdotal evidence that flushing a high-mileage tranny will cause it to screw up, but I have heard of this happening. I would not do a flush for the first time on a high-mileage tranny: Drop the pan & drain the fluid, replace the filter, & call it good.

Thanks to all who answered here. I took all your advice and have a quick followup. So I took the KJ in Saturday, and when I explained my situation, the shop agreed with me on the high mileage tranny. I took them my own synth fluid (5 quarts) and let them at it. They only dropped the pan and replaced the 2 filters and refilled. When I get the call that the KJ is ready they tell me I needed to add approx. another quart of fluid and they didn't want to add their own synth to my synth I provided, and I said no problem. Thanks not just dumping another brand in there.

Long story short...its running perfect but I have an inquiry. I get home and check the dipstick before I add anything. The car was hot so I was dealing with that variable. It read about a quart low...the fluid showed just between the "add" hole and the "cold" hole. Reading the Haynes manual, sure enough it says a quart will basically take the reading from the "cold" level to the "hot" level and I thought "great, the shop was right on". So I add only a half a quart at first....wait a bit then take another dipstick reading...it still showed that it was a bit low. So I add the rest of the quart and it seems to be right where it should....

The next morning, I open the hood before work to take another dipstick reading....this time I want to see it as a cold reading after sitting all night. This time I take the reading when its cold and it shows its full....right up to the "hot" hole in the dipstick....my question is, "Am I overfilled???" I have driven a round trip to work (75 miles on the highway) and took a reading when I got home and it's still showing full...about the same level as when it was cold this morning....no fluid has seemed to foam over at the dipstick and it seems fine. But how do I know I'm not close to being too full? are there tell tale signs if the tranny is too full? can I do damage? am I ok if its just slightly overfilled? what should I look for....or do I just continue to run as normal....it sure drives great, rpms are perfect, etc....

what do you guys think....ok to go or keep a close eye on it and continue to worry....could a half of quart put me over the top somehow lining me up for damage or am I worrying about nothing. thanks so much guys.....always a big help.
Dave

Jeepjeepster · **Posted:** Tue Jun 17, 2008 12:01 pm

When you read it cold, did you have the engine started and tranny in N? When I read mine with the Jeep not running, its way up on the dipstick where it bends.

If I read it (even if its cold) with the engine running and tranny in N, it reads right on hot.

tjkj2002 · **Posted:** Tue Jun 17, 2008 2:20 pm

Yep you nneed the engine running and tranny in "N",also it's a good idea to place the gear selector in each postion before checking the fluid level,that means placing in "R","N","D",2,and 1 and then place back into "N".Don't forget to set the parking brake,though you should be on level ground anyway.Always check the level when hot,never cold even if the dipstick has a cold full line(that means go and drive for at least 15-20 mins).

Oh and plus the little add to full line is not 1qt,it's 1 pint.You never want to overfill a auto tranny,very bad,but a little low is not all that bad to it,way better then being overfull.

Pote · **Posted:** Tue Jun 17, 2008 3:14 pm

tjkj2002 wrote:

Yep you nneed the engine running and tranny in "N",also it's a good idea to place the gear selector in each postion before checking the fluid level,that means placing in "R","N","D",2,and 1 and then place back into "N".Don't forget to set the parking brake,though you should be on level ground anyway.Always check the level when hot,never cold even if the dipstick has a cold full line(that means go and drive for at least 15-20 mins).

Oh and plus the little add to full line is not 1qt,it's 1 pint.You never want to overfill a auto tranny,very bad,but a little low is not all that bad to it,way better then being overfull.

thanks....and thanks for correcting me, I meant to say pint to change from the cold to hot level. So with that said, how does one know if he's overfilled?? I read in Haynes that the transmission could foam...whats that by definition and foam where/fromwhere?? If my level reads at the hot level no matter when cold or when running, am I ok?? what signs of overfill can be looked out for?? will it literally foam up and out the dipstick tube? or does it leak out the seal at the pan?? just curious. an oh....would I be dangerously full if it took a full 6 quarts? is that within reason that a tranny refill could be 5-6 quarts...or is 5 just what it needs....maybe 5.5??

tjkj2002 · **Posted:** Tue Jun 17, 2008 3:25 pm

Every tranny will take a different amount for a drain/refill,depends on tranny fluid temp and such as to how much fluid is lost.If the fluid level doesn't change from when checked cold to hot there is a problem since hot fluid expands.The "foaming" you are talking about is airation(air is mixed with fliud),the fluid will look some what like a strawberry milkshake(will also look this way if water is in the ATF also).

Just keep checking it,tranny fluid levals are some of the hardest to determine,it has taken me over a hour before to get a good(consistant) reading from a tranny dipstick(not from my KJ though).

sleeve84028 · **Posted:** Tue Jun 17, 2008 3:39 pm

I would add, that a hot transmission will be harder to get an accurate read from since you'll have been driving for a while and the fluid mgiht have splashed everywhere. But - Hot fluid is exapnded and thus, it's best to check your fluid level while hot. That is, in my eyes, the truest measure of the fluid level in your transmission.

Need a concise summary of pros vs cons on tranny UPDATE

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