J Mod

[Bigmatthew86]

I’ve had my 5.0 swapped Ranger for a while now & never knew what had been done to the transmission. It shifted pretty hard 1-2 so it was obvious something had been done. I bought a new valve body with the sonnax upgraded parts & proceeded to j mod it. I drilled the holes to .100 like the instructions said. I also removed the lower 1-2 spring & removed the 2-3 spring. Trans now actually shifts much softer on the 1-2. 2-3, 3-4, & downshifts have improved. I actually wish the 1-2 was firmer like before. It’s firmer than my stock 2000 mountaineer but it doesn’t chirp 2nd on a wot shift anymore. I need to take the plate out of the stock valve body & see what size holes it has. If you’re running a stock 4r70w I would highly suggest doing it as it is much improved.

 

[franklin2]

I have heard you can have too much of a good thing. Really hard shifting can be hard on the band connections, eventually snapping them.

 

[Bigmatthew86]

I can buy that. I’m going to pull the valve body again. I believe I followed the instructions for a 98+ body so I didn’t address a few holes I should have. I would have been fine with a little easier 1-2 shift but I made it feel stock again. I have the old style pan so I’m going get a newer style with a drain plug. I’ll update after I pull it again.

 

[fastpakr]

What's the source for your transmission? I've got an Explorer 5.0 trans in mine and never found a clear set of JMOD instructions for that valve body.

 

[Bigmatthew86]

It’s a 96 explorer tranny. I bought a valve body off eBay. I too had read the truck valve bodies responded differently to the j mod. I also read where guys just modded the truck separator plate & it was fine.

 

[Bigmatthew86]

Ok I pulled the valve body back off this morning and the holes I didn’t drill are already the size they should be. The old valve body had a transgo gasket so I’m wondering if it has a transgo shift kit in it & that is where the difference is? Where do I go from here? I really just want the 1-2 shift firmer so do I drill that hole out a little larger? I did .10 but can step up to .125.

 

[superj]

no idea but i am going to follow along since we just did a transgo in my wrangler automatic but haven't gotten to actually drive it since it now won't start. stupid jeep

 

[Bigmatthew86]

Got it all back together. I drilled hole #2 out to .125. Also added the newer style pan w/drain. It did what I wanted it to. It shifts how I want it to now, not too hard off the gas & will bark 2nd wot.

 

[JoshT]

Questions, questions, questions...

Finished up the 5.0 AWD swap on my 99 this past weekend and been driving it this week. The shifting has got to improve. Actually it may have this afternoon. after I think that I fixed a big vacuum leak between the throttle body and intake. Doesn;t make sense to me that fixing a vacuum leak in the intake would improve shifting, it definitely felt like it was shifting better. Maybe just a side affect of running better.

Anyhow more improvement would be better and have been skimming over the jmod and shift improvement stuff the last few days recently. Going to have questions.

First, you said you bought a valvebody off eBay. What application was it for? My trans is a 2000 AWD, but I've actually got a "spare" 1998 2wd transmission. I was thinking about using that valvebody as the basis of the modification then swapping it in once done. From what I've read those two transmissions should likely have the same valvebody.

Which Sonnax parts did you buy/use?

So first time around you drilled all the jmod holes to 0.100 inch? That gave improved shifting compared to the Mountaineer, but still soft?

I had others when I forst read your thread a few hours ago, but I can't recall what they were now.

Being an AWD setup I don't know that I want it to chirp second, if it were even able to. Gradual improvement is kind of the route I was figuring to take for the jmod. Minimum recommended sizes and see how it responds, with later upsize for particular shifts where/if desired.

Pretty sure this is going to happen in the near future. I've already got the larger pan 4wd pan and we added a drain plug while it was off. New fluid, filter, and gasket installed. As long as I can keep the fluid clean I should be set to drain, drop the pan, swap, and reassemble.

I guess my biggest hangup at moving forward with this are, can I use the '98 valvebody and what Sonnax (and/or other) parts do I need to order?

 

[Bigmatthew86]

If you want to start off small you can pull the 1-2 bottom accumulator spring. If the pan’s off you don’t even have to drop the valve body for that. That might get you to where you want to be alone. The 00 valve body had many of the holes enlarged already & you probably don’t need to add the sonnax parts unless you just want to. If you have a spare valve body you can definitely do it so when you pull yours you can just swap them out. Mine with a .125 hole for 1-2, & .100 for 2-3, & 3-4 as well as bottom 1-2 spring & 2-3 spring removed shifts exactly how I want it to. It’s not even hard on the 1-2 unless you’re wot. But it’s a lot easier to enlarge a hole that shrink one.