Replacement automatic transmission filter review

[Jonathan]

This is a review-in-progress as it only went into my car a hundred miles ago, but I wanted to share how the car has been doing before, after and during.

My car is a Sept 81 build with the automatic trans. I bought the car in 2007. At the time, it had many, many surprises, most small and some medium.

One of those was needing to rebuild the shift computer (governor). My shift computer failed in such a way that it held the gear late, and such would shift from 1st to 2nd at about 55 km/hr and 5,000 RPM and likewise from 2nd to 3rd at about 90 km/hr. Not fun as you can imagine when coupled with a brake system needing an overhaul. I had the rebuilt option from DMCMW put into the car and all has been well since then.

The fluid was changed back then (2009 or so) and I also changed it in 2013 after developing a dipstick tube seal problem/leak. When I fixed the dipstick tube seal, I took the pan off but did not attempt to remove the original filter to inspect nor clean. I was not a big fan of the option of cutting it open to clean and then reassembling it with the copper tube around the outside edge solution.

I would estimate I have put about 10,000 miles on my car since those first couple years when I put close to no miles on it. That included driving it from Ontario to Ohio last summer for DCS. The overwhelming majority of the problems with my car have all been addressed and missing or worn out parts have been replaced, including both mechanical or electrical as well as interior or cosmetic.

A couple weeks ago I found out that something was not right with the transmission. I thought a couple times earlier in the season it felt like it was almost in neutral briefly but passed it off as my imagination or maybe my foot slipped off the gas. Then on my way to meet another owner passing through town, I could no longer ignore it.

I didn't get even a mile away from home and on the main road to where we were meeting, I lose forward power, just like it is in neutral. I realized quick it was happening and got into a parking lot to figure it out. I pull into a spot, shut the car off to see if anything looks leaking or melted. Nothing did and I turned it back on. Wouldn't you know it, my forward power came back! I eased out of the parking lot trying to figure out where I could go to get home or to the restaurant making only right turns among the busy getting home from work crowd filling the streets.

At the next intersection though, I lose power again like it is in neutral and coast into another parking lot. I call the other owner and when he gets to the car, we park together and go into eat nearby. He offers to act as an escort at low speeds taking the back way home and if I lose power again, I'll put the flashers on, pull over, shut the car off and restart it and hope that works to get me home.

It did. I got it back home and as if there were some greater DeLorean force looking out for me, Michael posts his "auto trans filters are now available again" thread that same night. Woo hoo!!

I ordered two before the end of the night and in that next few days before they arrived, drained the fluid and dropped the pan. The fluid looked more or less ok and was still a nice colour and smelled ok too. My filter though... well, you be the judge. Does it look plugged to you?

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By the time the filters arrived in the mail, which they were well packed and in nice condition with the cork gasket and replacement magnet, I had more than a couple chances to email with Michael about my car and the filters. He was very helpful in explaining some of the history on the filters, what went into the remaking of them and some suggestions he learned form his own experiences trying the new ones out.

This may be somewhat of a side note to the filters, but I was also very happy to have had that chance to get to know Michael on a more personal note. For any of you that have been around the forums long enough, you know that none of us are always in our best form. I am for certain guilty of that at times and was thrilled that we both kind of acknowledged it and moved on. Life is too short to judge each other from the past... regardless of any time travel jokes

I got my new filter installed and filled the ATF to the proper level. My pan was off or draining a little longer than typical, so instead of about 4 quarts (litres for me!) I was closer to five going in to get it right. I went on a couple cautious test drives and all has been good so far. I intend on proactively changing the fluid again and perhaps dropping the pan as well to do a visual inspection after a couple hundred miles.

It sometimes goes without saying, so I wanted to make a point of saying it regardless, but Dave Swingle from DMCMW was very helpful in all of this as well. Not sure where I would be without his help, and suggestions on auto trans fluid filter problems is another chapter in his very extensive lesson book.

I am still working through a couple idle related issues with my oxygen sensor so I'm trying not to get jumpy if it feels sluggish when first setting out as I believe these are not directly related to the trans fluid. What I think ultimately happened to my trans when that filter got plugged enough to really pinch off the pressure is that it left an inadequate amount of fluid to operate the hydraulics. Time will tell if I was smart or lucky enough to baby it home and not have had it happen on the highway at higher speeds.

When I turned the car off and on again I think it restored the power temporarily because the sediment that was stuck in there relaxed briefly and then let me drive it further until it got lodged back in there again. That's my theory and I think it is what happened until I prove otherwise.

I will update this thread as time goes on and I get some more miles in the car with this new filter. Ultimately I wanted to share this with you to let you know how my experience went and to thank Michael publicly for taking the time and effort and considerable investment to provide replacement auto trans filters to the community when they had been NLA for so long. Thank you.

EDIT: Here are the replacement filters when they arrived and I unpacked them:

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One additional piece of context for the two weeks leading up to my problems, was that I had the car in the air on ramps with the rear higher than the front while I was under just cleaning the frame and doing other random detailing. I suspect this odd angle might have let the sediment collect all in one spot and that's why the plugging was so dramatic from the time it happened briefly to when it happened in a full blown way. The night I set out to meet the other owner was the first time I drove the car after getting it down earlier that day.

[Nicholas R]

Best of luck! That old filter was definitely in pretty rough shape. I'll be that the majority of auto transmission filters look like this by now...

These filters are really great work. My hat truly is off to Michael for putting the time and effort in to making such a great part that has honestly been way overdue. If I still had an automatic, I would definitely have been one of the first on his list of buyers.

This is one thing I love about this community. Dont get me wrong, we have some really good vendors, but sometimes there are still gaps, and usually we have owners that are willing and capable to fill those gaps. This is a perfect example of that. Anyone that sells DeLorean parts or services DeLoreans should be getting these from Michael by the dozens!

Amazing work Michael and best of luck from here forward Jonathan

[Michael]

Thanks Nick and Jonathan, I am very glad to hear everything is working out.

I would be very interested to know if anyone notices any improvement in the low end response or if it's just my imagination. Here is what I am talking about. Back in the 90's or maybe even early 2000's, there was some concern that the OE filters were just too restrictive. I never paid it much concern considering these cars are 30+ years old now and no issues, but one of the things my manfacturer pointed out was they also felt the mesh filter was a little too dense and wanted to open it up just a little to help flow. Since I had also read this in the DML archives, I went with their recommendation and life went on.

When I started testing the new filter, I noticed a bump in response out of the hole. In the past with the original Renault filter when I left from a stop, the car moved forward immediately but it just didn't seem like I was locked until a second later. Not excatly slipping, just like I had a mini stall converter. The response was slightly delayed. I remember even starting a thread on the subject 7 years ago when I first bought my car wondering if this was normal.

Now when I hit the throttle from a stop, it's much more responsive and quicker to engage now.

During my research, I had read time and time again that people who ran without a filter said the car ran better, which I knew was BS since the transmission filter had nothing in common with the engine performance, but now I think they meant the car's performance in general. My theory is that the OE filter's mesh was so dense, it was on the verge of starving the clutches at idle. They were still wet of course, but it took a second for the pressure(or suction) to get enough fluid to the clutches once the RPM's rose. I don't know how plausible that theory is, just trying to make sense of the improvement.

I did do three transmission services within a few months of each other during testing so it could just be that I effectively flushed out the transmission and that's what made it run so well. Or it could all be in my head so if anyone notices an improvement (or no improvement) in throttle response let me know as I'm curious and it would make a great selling point to boot!

[Lwanmtr]

These look great. Im still getting my engine going and will most likely flush transmission and change filter soon too, so this is on my list to get.

[StanMan PushN 88]

I ordered but haven't had time to swap it out yet. Is this something that's fairly easy to get to? Do you have any pictures of it in place on an actual car by chance a video you can shoot and post showing it and what tools to use (I'm not a mechanic) Does car need to be on a lift and is it something you can get to by sliding underneath car engine?

Thanks,

"Pushing 88"

[Michael]

You would need at least jack stands but I don't like working under them. I prefer a solid and safe lift w/saftey catches.

If you can change your oil you can service your tranny. Drain fluid,(I use a clean pan to drain in and inspect the fluid under a flashlight just to make sure there are no red flags). Remove the 12 or so bolts and remove the pan. 3 bolts hold filter in place. Make sure there is no cork gasket from the old filter on the valve body before fitting new filter. If you have one, clean the old magnet off and place back on filter, the new magnet can go in the pan corner. Also give your valve body and case a visual once over. Look at the o rings and seals and make sure they are in good shape. Clean all gasket material off case and pan, then you will need to clean out the pan entirely and reflatten the mating surface. The surface gets distorted from being tightened down. Use a small hammer or mallet and knock all the humps around the bolt holes down flat.

At this point you either need the pan gasket Josh at DPI sells or use Right Stuff gasket maker. Replace your pan and refill approx. 4 qts. (I'm not sure but if you use gasket maker then you may need to let it set up first before replacing the pan..if so it may take more than 4 qts since the fluid in the valve body will work its way out over time). Once the tranny warms up you can zero in the fluid level.

As far as how tight to tighten the filter and pan, I'm sure the tq. Specs are in the manual but I do not know what they are. Just snug them down good, no need to go overboard and rip threads out.

[Redsquall]

Thanks Michael!

You would need at least jack stands but I don't like working under them. I prefer a solid and safe lift w/saftey catches.

If you can change your oil you can service your tranny. Drain fluid,(I use a clean pan to drain in and inspect the fluid under a flashlight just to make sure there are no red flags). Remove the 12 or so bolts and remove the pan. 3 bolts hold filter in place. Make sure there is no cork gasket from the old filter on the valve body before fitting new filter. If you have one, clean the old magnet off and place back on filter, the new magnet can go in the pan corner. Also give your valve body and case a visual once over. Look at the o rings and seals and make sure they are in good shape. Clean all gasket material off case and pan, then you will need to clean out the pan entirely and reflatten the mating surface. The surface gets distorted from being tightened down. Use a small hammer or mallet and knock all the humps around the bolt holes down flat.

At this point you either need the pan gasket Josh at DPI sells or use Right Stuff gasket maker. Replace your pan and refill approx. 4 qts. (I'm not sure but if you use gasket maker then you may need to let it set up first before replacing the pan..if so it may take more than 4 qts since the fluid in the valve body will work its way out over time). Once the tranny warms up you can zero in the fluid level.

As far as how tight to tighten the filter and pan, I'm sure the tq. Specs are in the manual but I do not know what they are. Just snug them down good, no need to go overboard and rip threads out.

[Michael]

Thanks Michael!

You're welcome! Please note that I have been told that "The Right Stuff" gasket maker can be awfully hard to get to break loose to the point of damaging your pan. Better to be safe and go with Josh's (DPI) silicone gasket.