Thoughts on Lucas transmission stop slip?

Revans381996

Original poster
Member
Dec 18, 2013
41
I wanted to see what our gmtnation community thought about putting Lucas stop slip in our trannies. Personally I put the stuff in my trailblazer when i changed my transmission fluid for the 2nd time. I was dealing with a hard 1-2 shift only when cold but otherwise the tranny shifted fine but after I changed the fluid and put in stop slip my hard cold shift went away completely. So what are your guys's thoughts on this product? Good or bad?
 
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The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Personally, I've heard very very bad things about patch products like radiator stop leak. The way they work is almost guaranteed to have side effects like gunking up DESIRABLE fluid passages.

I've got no hard data or research, but I assume you Googled before using the tranny stop leak. What did YOU find? Asking after you performed a potentially unrecoverable process isn't the best way to proceed.

In general, you should strive to fix the root cause and not apply patch-up products. Not knowing the root cause, and I'm starting to have loose 1-2 shifts at 110K miles, would make me do a bit of research and put in the traditional upgrade parts like a Transgo kit and Vette solenoids. Fix it right if you value the truck.
 

Revans381996

Original poster
Member
Dec 18, 2013
41
First off the product is stop slip not stop leak. I didn't really google anything before using the product I just talked to a few competent mechanics who recommended the stuff. Also a few people on YouTube used it and said it worked well for their vehicle. Like I said, my transmission wasn't having real problems but a little hard shift from 1-2 only when cold but I think that's pretty normal for a transmission with 160,000 miles. I used the product and I believe it helped shift quality a bit so i like the product.
 

kkeo211

Member
Apr 14, 2014
87
I have a bottle of it after my transmission started acting funny (hunting gears on the highway, later found out I was a little low on fluids). It is currently sitting on the shelf, because after buying it, I googled the product and saw all types of reviews. Some swear by it and use it without doubt, some say it will destroy even a health transmission. The reviews on Amazon are 4 stars. I've decided I'll only use it if I have an emergency.
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
My thought on this is that if it did "fix" anything, dealers would be using it for warranty repairs instead of overhauling transmissions with glazed or cooked clutches.

I'm against all additives (seafoam, 44K, techron, etc) so I am a little biased. But, stuff like this does swell up clutches. If there was a transmission slipping issue, and adding this could get someone by for a few weeks to look for a new car/save a few checks for a rebuild/etc, then I'm all for it.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
It is THICK stuff. I like most Lucas stuff, but would not use it unless I was trying to nurse along a busted tranny until rebuild or replacement. It helps hide issues, but does nothing to actually fix anything. I used Tranny Honey to milk along a blazer for over a year. It would start slipping and I would add some more. It worked to stop the slip, but never really fixed the problem and one day the trans just let go completely.
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
MAY03LT said:
My thought on this is that if it did "fix" anything, dealers would be using it for warranty repairs instead of overhauling transmissions with glazed or cooked clutches.

I'm against all additives (seafoam, 44K, techron, etc) so I am a little biased. But, stuff like this does swell up clutches. If there was a transmission slipping issue, and adding this could get someone by for a few weeks to look for a new car/save a few checks for a rebuild/etc, then I'm all for it.

I agree. What does this product do to change the shift? De glaze the clutches? Make the trans fluid slipperier (is that a word?)
Myself I'm VERY wary of trans fluid additives.
Back in the day when rebuilding a trans, we could spot someone who used additives because when the clutches were dis assembled and the seal removed, it was so swelled I used to wonder how it ever fit.
Then again, to get a guy by for a few weeks, a couple of ounces of brake fluid in the trans worked wonders. Swelled the seals, helped the slipping. Wouldn't do that in todays cars.
 

Sparky

Member
Dec 4, 2011
12,927
Yeah, last ditch effort to limp along until replacement. Never really a fix.

My brother used this "engine honey" stuff in his crankcase on his old car to keep the oil PSI high enough at idle because the engine was so worn. Kept it going for over a year that way but eventually it did blow completely.
 

IllogicTC

Member
Dec 30, 2013
3,452
MAY03LT said:
My thought on this is that if it did "fix" anything, dealers would be using it for warranty repairs instead of overhauling transmissions with glazed or cooked clutches.

I'm against all additives (seafoam, 44K, techron, etc) so I am a little biased. But, stuff like this does swell up clutches. If there was a transmission slipping issue, and adding this could get someone by for a few weeks to look for a new car/save a few checks for a rebuild/etc, then I'm all for it.
This makes sense. After all, using less products (whether parts, or fluids) and/or time when fixing a problem under warranty means more in their pocket if they're to be reimbursed by the warranty program, isn't it?

Also, for those whose vehicles are under warranty, I'd take it to the dealer before putting this stuff in it as it may void the warranty. Pretty well have to follow the book and use only genuine GM/ACDelco, Mopar, Motorcraft parts (just using the names for the Big 3, other manufacturers have their own) or they can screw themselves out of their warranty.
 

gmcman

Member
Dec 12, 2011
4,656
How many miles are you at? Tranny's don't last forever so if you are at maybe 130-140K I would recommend replacing the separator plate and install a vette sero and Sonnax super hold servo.

This will add life to the very soft shifting setups we have. I did mine at 167K and 35K miles later no slipping...I had a 2-3 slip at arounf 165K.
 

DocBrown

Member
Dec 8, 2011
501
I'm not a fan of this kind of thing either. When it comes to transmissions, if something isn't right, it needs to be fixed right. Hard shifts, sloppy shifts, and clunks are all part of owning a 4L60E. Best thing I did to mine at 150k was to put in a Transgo shift kit, replace the seperator plate, and replace the plastic actuator pistons. Got rid of the sloppy shifting.

You have an '03. I hope you are using Dex VI and not Dex III. Dex VI is much better, runs cooler, better lubricant, and is backward compatable.
 

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