Results 1 to 8 of 8
  1. #1
    Newbie
    Join Date
    May 2019
    Location
    Brisbane southside
    Posts
    5

    Default Trimatic - no forward gears

    G'day all, I recently bought a motor/box combo (253/trimatic) for a HZ v8 conversion. The box was already bolted up to engine and was supposedly rebuilt. Had new modulator and converter aswell as RTS high volume pan. I was told converter had no fluid and yes I know I should have removed it and filled it before dropping the lot into car but thought It would be fine and just require more fluid.
    Anyway, I've filled it with around 12L of fluid, reading full on the stick when warm and running but I only have reverse, neutral and Park???
    I have worked the selector back and forth through each gear for a solid 30 mins or more with no luck at all and can't find any info online or anyone that's had the same problem? Hoping theres some trimatic gurus on here that can help??
    Cheers.

  2. #2
    254RWHP boat anchor EVL253's Avatar
    Join Date
    Nov 2006
    Location
    bathurst
    Posts
    5,244

    Default

    when i blew one up a lot of years ago it had no forward only reverse.

    the if i remember correctly what its called the servo piston had broken. which means no band apply. which is common.

    need to remove the trans pan. its under a cover in one corner that has 4 bolts to remove. will soon know if its broken.

    DO NOT under any circumstances try to remove the clip holding the servo piston in place if its not broken. its under tension and if it lets go could cause some serious injury!

    have a look through here for a thread called home built trimatics. its where i built mine with help from HQ368. heaps of pictures that show from start to finish on building a trimatic.
    11 second E85 bottle fed boat anchor

  3. #3
    Do you ever leave?
    Join Date
    Jul 2009
    Location
    Sometimes Melbourne
    Posts
    2,419

    Default

    If it is the servo piston blown out, could be for a number of reasons.
    Remove the modulator and see if someone has made the pin longer.....

  4. #4
    Newbie
    Join Date
    May 2019
    Location
    Brisbane southside
    Posts
    5

    Default

    Thanks heaps to those that replied with help, it turns out there was no servo pressure due to loose bolts on the servo cover- they were finger loose! Tensioned them, checked other bolts and put it all back together- hey presto I now have all forward gears!
    Now i have a new problem though, the upshifts are quite harsh and I have no kickdown... it downshifts as I slow down but won't kick down on acceleration or uphill???
    Putting it out to the pros again.
    Appreciate any and all help.

  5. #5
    Do you ever leave?
    Join Date
    Jul 2009
    Location
    Sometimes Melbourne
    Posts
    2,419

    Default

    Loose bolts doesn't fill me with much confidence about the rest of the box
    .
    Shift quality, check vacuum port in manifold is clear first and then modulator pin length, see if it's been altered at all. You'll be able to tell.

    Kick down will most probably be the pedal switch if all wiring is in place and verified. Pedal switch can be reset by pushing the lever all the way forward and then WOT on the accelerator pedal.
    Make sure engine is not running when you do this......lol

  6. #6
    Newbie
    Join Date
    May 2019
    Location
    Brisbane southside
    Posts
    5

    Default

    Re the loose bolts- I know...my thoughts exactly...
    Cheers for the other suggestions mate. To check modulator pin length I just drain fluid and remove modulator?

  7. #7
    Newbie
    Join Date
    May 2019
    Location
    Brisbane southside
    Posts
    5

    Default

    HQ368, should the kickdown switch "feel" spring loaded and slide easily after the resetting procedure you mentioned? Mine doesn't at all.
    I pushed it all the way forward until it met some resistance and clicked, then WOT until it clicked again but it doesn't appear to return to its point of contact with pedal as I think it should.
    Is it common for these to fail or bind up?
    Cheers.

  8. #8
    Do you ever leave?
    Join Date
    Jul 2009
    Location
    Sometimes Melbourne
    Posts
    2,419

    Default

    Modulator pin, just spin it out mate, it'll drain out through there a little. No need to drop the pan.
    If it does have a drain plug then that's obviously the cleanest way.
    Pin will look similar to a roll pin and open both ends.

    Switch doesn't really make contact until almost WOT. I cant recall ever seeing one fail.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Wanted- Trimatic/m20 Speedo cable gears (Sydney)
    By gtrboyy in forum Wanted (cars & items)
    Replies: 12
    Last Post: 08-04-2016, 11:08 PM
  2. ten bolt diff 4.44 gears suit 1 tonner, v8 trimatic
    By b-fair in forum For Sale Items
    Replies: 2
    Last Post: 16-05-2012, 05:57 PM
  3. Forward facing bonnet scoop NSW
    By AGR071 in forum Legislation, and modified car laws
    Replies: 1
    Last Post: 09-05-2011, 09:48 PM
  4. trimatic planetary gears
    By Q boat in forum Holden V8's
    Replies: 11
    Last Post: 17-09-2008, 07:53 PM
  5. holden v8 trimatic speedo gears?
    By rlj308 in forum Holden V8's
    Replies: 16
    Last Post: 07-09-2008, 12:11 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •