AW4 shifting hard

[Sidewinder CC]

If your flex plate bolts are tight and there are no cracks in the flex plate try this test.

If the fluid level does not drop, as specified, there's a chance the torque converter is bad or the transmission oil pump is bad. Not a conclusive test but has shown bad torque converters in the past.

 

[old_man]

Just for your info. Most transmission "fix in a bottle" are little more than lacquer thinner. It breaks down the varnish and causes the rubber in the seals to soften a bit and swell, making a better seal.

A pint in a tranny is the recipe many shade tree mechanics use.

 

[Felipe Tiago]

If your flex plate bolts are tight and there are no cracks in the flex plate try this test.

If the fluid level does not drop, as specified, there's a chance the torque converter is bad or the transmission oil pump is bad. Not a conclusive test but has shown bad torque converters in the past.

I've done this test and surprisingly it went as it should. The level was almost in the curl part of the dipstick before I started the engine and then it dropped to the "ok" mark just after I started it.

The strange thing is that this was the very first time I got a reading below the max level mark, it was always above that when tested as per the manual (hot and in neutral) and even when cold... I don't know what happened this time.

 

[Felipe Tiago]

Just for your info. Most transmission "fix in a bottle" are little more than lacquer thinner. It breaks down the varnish and causes the rubber in the seals to soften a bit and swell, making a better seal.

A pint in a tranny is the recipe many shade tree mechanics use.

So a pint of thinner? How long do I leave it in there?

 

[8Mud]

When DEX 3 started to be hard to find here I went to a wholesaler to check on buying bulk (5 gallon cans). Heard from the wholesaler no problem, Mercedes specifies DEX 3 in many of their trucks and they keep it in stock. Mercedes specification MB 236.1 (MB 236.10 and MB 236.12).

Worth a call to a Mercedes truck repair garage and asking if they have DEX 3, or a wholesaler. Likely to be way cheaper than having it shipped by the quart.

Check your TV cable adjustment, most always the first place to start.

 

[Ecomike]

Just for your info. Most transmission "fix in a bottle" are little more than lacquer thinner. It breaks down the varnish and causes the rubber in the seals to soften a bit and swell, making a better seal.

A pint in a tranny is the recipe many shade tree mechanics use.

That is correct. My A-mechanics mentor from the early 70s that gave me my first lessons told me that. He had a custom 15(?) speed VW with a 12 (or 18?) hp Briggs and Straton in the great deperesion when he was in high school, LOL.

Lacquer thinner I am pretty sure is stronger that Trans-X with no lubricants, so I would not use more that about 1/2 of a pint at a time. they also used cracked pepper to stop radiator leaks on the race track during a race. I actually used it several times myself on a 78 Dodge fullsized stationed wagon, 78 that I put about 450,000 miles on, it was a 360 V-8.

 

[Ecomike]

So a pint of thinner? How long do I leave it in there?

About 1 hour of just parked running in neutral (parking break on with tire chucks) and some occasional shifts and hold in gear for say 1-2 minutes each should be a good start. Then let it sit over night, then warm it up just a little (5 min) again before draining it is what I would do.

 

[Ecomike]

That sounds like a pump problem coming and going?

"The strange thing is that this was the very first time I got a reading below the max level mark, it was always above that when tested as per the manual (hot and in neutral) and even when cold... I don't know what happened this time."

Reading above the max level after a cold start is not good, too much fluid can burn up the fluid and transmission, at least on other brands, but that is odd that yours normal now? I would keep and eye on that.

 

[Felipe Tiago]

That sounds like a pump problem coming and going?

"The strange thing is that this was the very first time I got a reading below the max level mark, it was always above that when tested as per the manual (hot and in neutral) and even when cold... I don't know what happened this time."

Reading above the max level after a cold start is not good, too much fluid can burn up the fluid and transmission, at least on other brands, but that is odd that yours normal now? I would keep and eye on that.

Yes, it is my "normal". I had never had a reading below that level before, until yesterday...

BUT....

Well, in my way to work today (after that fluid level test) it shift better than ever before, serously, it was simply PERFECT! Shift speed and firmness. I didn't even know how good a jeep XJ could be, this is my first one and has been driving me nuts since the day I bought it.

The shifts were perfect from the first to the last one! Altough, the whining noise was still there... that's odd.

I was thinking of selling the jeep but now that I know how good it can be I really wanna solve this problem to keep it forever! Finally I know how XJ owners feel, LOL

Back to the problem:

I'm thinking of something that works for all gears since it shifts good all the time or bad all the time. Pump? Primary regulator valve? There's also the fluid of course, but it's kinda weird that sometimes it works sometimes it doesn't.

oh, and thanks guys for the info on the lacquer thinner... should I do it now or the intermittent problem points to another direction?

 

[Felipe Tiago]

The whine sound I hear when the jeep is cold (first 10 miles) is just like the one in this video I found on youtube:

 

[Ecomike]

"if it ain't broke, Don't fix it" I say. Just keep the 1/2 pint of lacquer thinner with you in the mobile jeep tool box for now.

Focus on the whine source and fix it, unless the whine is from the transmission?

 

[Ecomike]

That sounds to me like a bearing noise, possibly from the power steering pump or idler pully or alternator etc, but mostly the power steering I think. I know I have heard that sound before, usually been power steering pump noise in my case. Check the fluid level in it.

If it is the PW steering pump and the fluid level is normal, it will not go away. It may run like that noisy for a good long while before it dies, if you can stand the noise.

The whine sound I hear when the jeep is cold (first 10 miles) is just like the one in this video I found on youtube:

 

[Felipe Tiago]

I think it is from the transmission... my steering pump does make a similar noise and I don't mind since the worst thing that can happen is to gain more muscles when doing turns!

This noise is different, it only happens when the jeep is cold and it seems to come from underneath. Although, I'll take the belt of to check and rule that out...

But I think you're right... I'm overthinking about it but and it isn't broke already...

I'm gonna do all "fluid related" things in a few days and see what happens. It makes no sense to take the transmission apart if it is running good except for some harsh shifts sometimes.

 

[Felipe Tiago]

Hey guys! I've noticed something new and was hoping you should help me to figure out why this affects my shifts.

Here is the fact: my driveway is slightly inclined to the street and when I back the jeep out of the garage, step on the brake just to slow it down a bit (already in the street) and then put it in Drive with the wheels still spinning backwards it shifts perfectly until the next complete stop. (I know this is not good for the trasmission)

Now I know the hard shifts are not related to fluid temperature.... but why is this action affecting all the following shifts?

If you guys have any idea or thoughts about this, please let me know.

 

[old_man]

When in Reverse, the tranny kicks up the pressure quite a bit. Sounds like a leaking seal internally. Use some Trans-x or lacquer thinner to see if you can soften the seals and make things better.

 

[Sidewinder CC]

I've done this test and surprisingly it went as it should. The level was almost in the curl part of the dipstick before I started the engine and then it dropped to the "ok" mark just after I started it.

The strange thing is that this was the very first time I got a reading below the max level mark, it was always above that when tested as per the manual (hot and in neutral) and even when cold... I don't know what happened this time.

I'm wondering if your transmission is a tad over-filled.

This is from the FSM:

EFFECTS OF INCORRECT FLUID LEVEL

A low fluid level allows the pump to take in air along with the fluid. Air in the fluid will cause fluid pressures to be low and develop slower than normal.

If the transmission is overfilled, the gears churn the fluid into foam. This aerates the fluid and causing the same conditions occurring with a low level. In either case, air bubbles cause fluid overheating, oxidation and varnish buildup which interferes with valve, clutch and servo operation. Foaming also causes fluid expansion which can result in fluid overflow from the transmission vent or fill tube. Fluid overflow can easily be mistaken for a leak if inspection is not careful.

 

[Felipe Tiago]

I think I will drain some fluid, and drive it for a couple days to see if that helps.

Then I try the lacquer thinner...

 

[Sidewinder CC]

I think I will drain some fluid, and drive it for a couple days to see if that helps.

Then I try the lacquer thinner...

Drive it for at least 15 miles to get the trans fluid up to operating temp then check it immediately at idle, with the trans in PARK.

 

[jeremyj]

Drive it for at least 15 miles to get the trans fluid up to operating temp then check it immediately at idle, with the trans in PARK.

I've heard this a few times, but the dipstick itself specifically states to check it in neutral. However, I've checked it in both and haven't noticed a difference.

 

[Sidewinder CC]

I've heard this a few times, but the dipstick itself specifically states to check it in neutral. However, I've checked it in both and haven't noticed a difference.

I think the switch from neutral to park was a liability issue. Ambulance chasers at Chrysler were probably worried about people getting run over with the vehicle sitting there running and in neutral.

No difference in dipstick reading so WTF.