Lentech VB shift problem

[G-forces]

Background... I rebuilt an ATX with Alto upgrades and installed a Lentech valve body. It is full of Amsoil synthetic (Mercon V compatible) fluid. The trans ran great for about 900 miles. I wasn't aware that Lentech recommends a fluid change after 150 miles when using Alto steels (I was going to change at ~1000). When I changed it this weekend, there was allot of fine grit stuck to the magnet.

Problem... the car would not shift into 1st when "1" was selected, but WILL go into 1st when in "D". However, it would not shift into 2nd when in "D", but will when dropped into "2". Then would slowly (high rpm) go into 3rd when returned to "D". 4th/OD works normally.

I called Lentech and asked if this was a symptom of low line pressure (like from a clogged filter), Len said, "No", that I needed to disassemble the VB and clean it, and change the fluid/filter. I did, buttoned it back up, refilled, and I still have the same problem.

Anybody have any ideas what could be causing this?

Forgot to mention that it SLAMS into 2nd when it goes. There is always a delay going from 1st to 2nd then <bang> it hits 2nd. When going from 3rd to 2nd and back to 3rd, everything operates normally. 1st to 2nd and manual 1st are not working right.

[bustonit]

I'd follow Len's advice. He is the best there is.

[RallyRacer]

Yikes, something is not right.
You don't have to change the fluid at 150miles, and it's certainly not the cause of your problems. I changed it at 3000 miles after my rebuild with the new Altos to let everything wear in, and it's been perfect for 35k miles now.
This concerns me: "When I changed it this weekend, there was allot of fine grit stuck to the magnet."
After 900 miles? When I did the first change after rebuild at 3k, there was very little sediment attached to the magnet. How much of the magnet was covered and how thick of a layer of grit?
When you say it won't shift in manual 1st, do you mean it acts like it is in neutral or a higher gear?
Any CELs? Like "trs out of range"?
Could be a lot of things, I will check the symptoms chart in the transmission manual.

Also when you disassemble the valve body , use new gaskets. Soak the separator plates in gasket remover for 12hrs and peel and scrub the old gaskets off; and do not scrape, gouge, or warp the separator plates.

[G-forces]

Originally Posted by RallyRacer

Yikes, something is not right.
You don't have to change the fluid at 150miles, and it's certainly not the cause of your problems. I changed it at 3000 miles after my rebuild with the new Altos to let everything wear in, and it's been perfect for 35k miles now.
This concerns me: "When I changed it this weekend, there was allot of fine grit stuck to the magnet."
After 900 miles? When I did the first change after rebuild at 3k, there was very little sediment attached to the magnet. How much of the magnet was covered and how thick of a layer of grit?
When you say it won't shift in manual 1st, do you mean it acts like it is in neutral or a higher gear?
Any CELs? Like "trs out of range"?
Could be a lot of things, I will check the symptoms chart in the transmission manual.

Also when you disassemble the valve body , use new gaskets. Soak the separator plates in gasket remover for 12hrs and peel and scrub the old gaskets off; and do not scrape, gouge, or warp the separator plates.

The magnet was completely covered about a 32nd thick.

No CELs, it acks like it's in neutral when in manual 1. It starts in 1st in "D" though. Second takes a long time to engage, then slam. Before it went this bad though, there was already a delay when automatically downshifting from 4th to 2nd at WOT.

Oops, I already disassembled the VB and soaked for a few hours then gently nibbled the stuck side gasket off the separator plate. There were swirl marks but no topography digs or scratches.

[G-forces]

Okay, here's an update, for any of you thinking about a Lentech VB.

I took out the Lentech and swapped back in my old stock VB. Everything is back to normal, shift pressure increase now controlled by tune again, and all shifts are smooth. I sad to report, the problem was the Lentech VB.

Rally... Based on your experience with rebuilds, it sounds like my running it for ~1K miles shouldn't have been an issue for the VB. Based on Len's input, he thought the VB was goobered up with residue (they recommend 150 mile to the first change), but now I'm not so sure he was right (there was no difference after I cleaned it).

I'm going to call Len and see what kind of deal we can arrive at about fixing the "defective" VB. It always did hit second harder from the very beginning. However, since the first time I used it was also the first time I used the whole trans, I though that the harder hit in 2nd could have been due to the tollerences I built into the shift pack... but that is not the case. All shifts feel the same with the old stock VB and equal % increases in pressure via the tune.

What a relief the trans wasn't at fault! But for $500 I was expecting the VB to be right... we'll see.

[Lancer211]

Please continue to update this thread. I've been considering getting a Lentech VB, myself.

[RallyRacer]

Good to hear you got if figured out. I guess you got a defective VB.