Transmission Additives?

[bkang]

I have a 1999 Honda Odyssey with 124,000 miles. I had the transmission fluid replaced 4,000 miles ago and since that time I noticed a reduction in fuel economy by 2-4 mpg. I also noticed the transmission isn't shifting as smoothly in some of the gears as it did before. Maybe some minor slipping but it's hard to say for sure. I'm concerned the transmission fluid change has done some harm. I verified the transmission fluid is at the correct level on the dipstick.

I'm wondering if using a transmission additive like Lubegard or Lucas Transmission Fix could help in my situation? I know additives can't fix worn transmissions but I'm hoping to get some more life out of this transmission if I caught the issue early enough. If you guys recommend Lubegard, let me know which additive to use. They have different additives and I am not sure which to use in my case.

 

[martinq]

What transmission fluid was added and how much?

124k is not much use unless it's been neglected.

 

[bdcardinal]

What fluid was used at the last service?

 

[MrBubba]

Unfortunately transmissions in that generation of odyssey were notorious for failing even catastrophically causing accidents because they would lock up on the highway.

Using the correct fluid and not multi-vehicle fluid is important and servicing it frequently

Lubegard is the best additive if you feel like using an additive.

 

[meep]

I’d really want to know what kind of fluid was used, and if the current fluid level is correct. A 1999 should have a dipstick. The only fluids I would use in this are Honda oem or amsoil. We had 3 Hondas in this age range and all ran well with amsoil. I did not have food luck with the occassional attempt to test another fluid which claimed Honda compatibility. It sounds to me like they used a fluid that was thicker than oem.

Ps. Lucas is just stupid thick oil. I would not use that unless you are certain the line presssures are low. Lubegaurd has been excellent when I’ve used it but it’s not going to address the problem you are describing, I think.

 

[Dave9]

The typical cases I've seen are due to the original fluid becoming more viscous then someone puts fresh, thinner fluid in. If that is what happened, any additive that's a thickener might help, though I would add only a little at a time to see how it responds. If that doesn't work, change the fluid to something else - Honda fluid if that's not what was used.

 

[Lawnman23]

What fluid was used at the last service?

I feel this needs to be answered first and foremost before any additional diagnosis can be done.

 

[Spring Break '92]

Unfortunately transmissions in that generation of odyssey were notorious for failing even catastrophically causing accidents because they would lock up on the highway.

Using the correct fluid and not multi-vehicle fluid is important and servicing it frequently

Lubegard is the best additive if you feel like using an additive.

I was a Honda technician when these were relatively new. By now they all have gotten either a new transmission under warranty with an ATF 'jet kit' installed. If the gear that was failing due to overheating was inspected and deemed good, just the jet kit installed. The purpose of the jet kit was to direct ATF directly over 2nd gear for better cooling.

 

[nascarnation]

2-4 mpg loss is a monumental change.
I'd be looking at fuel trims to see if anything shows up there.

 

[meep]

I was a Honda technician when these were relatively new. By now they all have gotten either a new transmission under warranty with an ATF 'jet kit' installed. If the gear that was failing due to overheating was inspected and deemed good, just the jet kit installed. The purpose of the jet kit was to direct ATF directly over 2nd gear for better cooling.

We had a couple of these transmissions in the family. One had the jet kit - that was an mdx. We also had one in an odyssey. I don’t remember if it was jetted or not. Both vehicles died of accidents well over 100k miles and not transmission troubles. Both had amsoil in them.

 

[bkang]

What transmission fluid was added and how much?

124k is not much use unless it's been neglected.

Honda OEM fluid was used. I’m not sure how much fluid was added as it was done at the shop.

 

[bkang]

2-4 mpg loss is a monumental change.
I'd be looking at fuel trims to see if anything shows up there.

I did have the car looked at by a shop a while ago and they said fuel trims were fine and they didn’t see any codes appear when scanning the vehicle. They also did a test drive and didn’t see/feel anything abnormal.

 

[billt460]

I have a 1999 Honda Odyssey with 124,000 miles. I had the transmissionmission fluid replaced 4,000 miles ago and since that time I noticed a reduction in fuel economy by 2-4 mpg. I also noticed the transmissionmission isn't shifting as smoothly in some of the gears as it did before. Maybe some minor slipping but it's hard to say for sure. I'm concerned the transmissionmission fluid change has done some harm. I verified the transmissionmission fluid is at the correct level on the dipstick.

I have a similar condition. I was convinced the transmissionmission in my 1991 Ford F-150 was overfilled. (I have no idea who, how, or when this happened). But it wasn't by my hand.

I based this on a high dipstick level, with a lot of bubbling on the dipstick, and some leaking when parked and allowed to cool. The transmissionmission was operating fine with zero slippage, and good up and downshifting. (The vehicle has around 170,000 miles at this point, and the transmission is all original).

So I purchased one of those Holt fluid extractors that operate off an air compressor from Harbor Freight. (Very good product I might add). And I proceeded to suck over a gallon of transmission fluid out of the dipstick hole, before the unit started to suck wind.

I then slowly and carefully started to add fresh Valvoline Mercon Type F little by little, while driving short distances, returning home to check and add fluid on my LEVEL garage floor.

After several of these "drive & fill" attempts, I brought it up to mid level, between the "FULL" and "ADD" lines. This took almost the entire gallon jug of fluid, minus a pint or so. Now the transmissionmission upshifts very smoothly with zero slippage, as it did before.

But now it downshifts very violently when I smack the accelerator, and it kicks down to a lower gear. So I again checked the fluid level, and found it to be at the exact same mid level between, "FULL" & "ADD".

So I added the remaining pint left in the jug, which brought it up just shy of the "FULL" mark on the dipstick. This additional fluid improved nothing. I'm still blessed with this violent downshifting everytime I accelerate hard.

With hindsight being 20/20, I should have left well enough alone. All this whole escapade solved was now it doesn't drip, and / or leak..... That, and that automatic transmissionmissions are like women in their total unpredictability, when you try to help them by doing what you think is the right thing.

 

[bkang]

I have a similar condition. I was convinced the transmissionmission in my 1991 Ford F-150 was overfilled. (I have no idea who, how, or when this happened). But it wasn't by my hand.

I based this on a high dipstick level, with a lot of bubbling on the dipstick, and some leaking when parked and allowed to cool. The transmissionmission was operating fine with zero slippage, and good up and downshifting. (The vehicle has around 170,000 miles at this point, and the transmission is all original).

So I purchased one of those Holt fluid extractors that operate off an air compressor from Harbor Freight. (Very good product I might add). And I proceeded to suck over a gallon of transmission fluid out of the dipstick hole, before the unit started to suck wind.

I then slowly and carefully started to add fresh Valvoline Mercon Type F little by little, while driving short distances, returning home to check and add fluid on my LEVEL garage floor.

After several of these "drive & fill" attempts, I brought it up to mid level, between the "FULL" and "ADD" lines. This took almost the entire gallon jug of fluid, minus a pint or so. Now the transmissionmission upshifts very smoothly with zero slippage, as it did before.

But now it downshifts very violently when I smack the accelerator, and it kicks down to a lower gear. So I again checked the fluid level, and found it to be at the exact same mid level between, "FULL" & "ADD".

So I added the remaining pint left in the jug, which brought it up just shy of the "FULL" mark on the dipstick. This additional fluid improved nothing. I'm still blessed with this violent downshifting everytime I accelerate hard.

With hindsight being 20/20, I should have left well enough alone. All this whole escapade solved was now it doesn't drip, and / or leak..... That, and that automatic transmissionmissions are like women in their total unpredictability, when you try to help them by doing what you think is the right thing.

That's pretty much how I'm feeling right now. Should've left the transmissionmission alone lol. Though I'm not experiencing the violent shifts fortunately

 

[bkang]

The typical cases I've seen are due to the original fluid becoming more viscous then someone puts fresh, thinner fluid in. If that is what happened, any additive that's a thickener might help, though I would add only a little at a time to see how it responds. If that doesn't work, change the fluid to something else - Honda fluid if that's not what was used.

I think that could be what happened, the old fluid that I had was more viscous or had more friction in it. Both the old fluid and new fluid are Honda OEM transmission fluids

 

[bkang]

I’d really want to know what kind of fluid was used, and if the current fluid level is correct. A 1999 should have a dipstick. The only fluids I would use in this are Honda oem or amsoil. We had 3 Hondas in this age range and all ran well with amsoil. I did not have food luck with the occassional attempt to test another fluid which claimed Honda compatibility. It sounds to me like they used a fluid that was thicker than oem.

Ps. Lucas is just stupid thick oil. I would not use that unless you are certain the line presssures are low. Lubegaurd has been excellent when I’ve used it but it’s not going to address the problem you are describing, I think.

Thanks for the heads up about Lucas. The fluid level is between the low and max fill lines. I may give Lubegard a shot and see how things go. I emailed Lubegard about which additive to use in my case and to see what they say. They recommended Lubegard Synthetic ATF Protectant #60902.

 

[Donald]

I might question if they really used the fluid they said they used. Dealer or Indy shop?

 

[THORROMIG]

LubeGard Red has been my go to over the last 2 decades. I always use a full bottle for the 1st spill and fill. Then add an ounce per quart there after on fills and spills. Helped my 08 Acura TL with a shudder when I bought it with 64K miles. Use it in all my older rides and friends vehicles. Good luck...

 

[CleanSump]

Lubegard and Lubegard Instant Shudder Fixx were almost a requirement for GMs at one time.

 

[MrBubba]

Lubegard and Lubegard Instant Shudder Fixx were almost a requirement for GMs at one time.

There was a TSB for it in regards to the Shudder Fixx.