V8 automatic - no third gear - intermittent reverse

dmblbit

Active Member
Poor old car refuses to change up into third gear. Reverse works OK when cold, but won't work when car is warm (which can be awkward).

Have checked fluid level using Harvey's recommended method, and fluid is halfway between the two markers. Not sure whether to try putting more in or not.

Fluid looks clean and not burnt or smelly.

I have tried loosening the kick down cable a bit, but it wasn't really under any tension to start off with, and it has made no difference.

I think this might be serous but would appreciate confirmation from those who know please.

Sigh.
 
TOP and REVERSE faults are normally the rear clutch failing or failed. I don't think that with the fluid level you've got adding fluid is going to make any difference, and normally it's the clutch piston seal that fails, reducing pressure and causing the clutches to slip and burn out, and if that's the case the only way to fix it is to remove and dismantle the box and replace parts as required, or fit a replacement reconditioned box.
 
Fluid levels are notoriously difficult to obtain, just check it again to make sure, it's really a two person job, one to select each and every gear in turn and someone up front to dip the stick when back in park.
Remove the dipstick and dry fully ( don't put it back in the tube until your ready for a dip )
and ensure your engine idle is set correctly 600-650 RPM maximum.
If you are certain it's correct then your rear brake band is in need of adjustment
 
Rear band failure will affect REVERSE and engine braking in "1", it won't have any effect on TOP gear.
 
Indeed, but low fluid level will, if he has both low level and band adjustment issue then it's a fix in situ.
Hope this is the case, or as you say it's box out for a clutch fix
 
I've never had a low fluid level stop engagement of TOP, I've read in the WM that low fluid can cause it to drop out of TOP, but I've never experienced it, and low fluid always gives delayed engagement of gears, and there's no mention of that, so I'm sticking with the rear clutch as the cause. I'm sure the OP hopes I'm wrong....
 
I was going to top her up a bit anyway, but haven't got any ATF. Halfords only sell Dexron products so I've ordered Miller Type G on Amazon, which will arrive Monday. Oh well - patience is a virtue . . . . .
 
Double checked fluid level, and it's definitely halfway between H and L. Haven't got any fluid til Monday anyway.

Engine braking in 1 is occasional, but NOT happening most of the time.

Reverse works well enough when cold but not at all when hot.

I'm struggling to get at the rear band adjustment bolt through the stupid little hole in the transmission tunnel - am I just lacking in perseverance, determination, grit etc, or do I need a special tool? Or is it maybe easier to get at from underneath?
 
IIRC the rear band adjuster locknut is 3/4"AF, but the adjuster itself isn't a hex, it's more like a square. If you have intermittant engine braking that points towards a rear band problem, so if you have lost TOP as well then maybe you are working with 2 separate faults.
 
Update: Miller type g transmission fluid arrived and I have topped up and tested, but still no top gear.

I have unlocked the 3/4" locknut (it must have been tightened by a gorilla), but haven't got anything that will move the square adjusting nut which looks like it needs a special tool. An 8mm socket slips round, and 7mm won't go on, so the next closest looks like 5/16" AF, which I don't have (but have ordered).

I understand from Eigthofthem, that even if I am successful in adjusting the rear band, this will not resolve the missing top gear. So Harvey's right I'm afraid - we have two separate faults.

Looks like I need a replacement box :(.
 
I thought I ought to update this thread now that gearbox is back working again. I'll try to be brief. At Harvey's suggestion I got in touch with Andy (eightofthem on this forum) with a view to obtaining a replacement box, as I was sure mine was finished. He persuaded me to try a couple of other things before giving up, so here's what I did under his direction via email and text:
  1. Removed the transmission sump cover and checked all the pipes were properly located - as it turns out they were
  2. Replaced the rear servo with a new one supplied by Andy as the rubber seal was ruined
  3. Took the filter off and cleaned it
  4. Replaced the sump pan with a better one supplied by Andy
  5. Adjusted the kick down cable while could see the business end of it
  6. Reassembled transmission
  7. Adjusted the rear band using a special tool made and supplied by Andy
  8. After refill and test drive we now have functioning reverse, but still no third gear
  9. Back up on the ramps again, and removed the tail
  10. Dismantled and freed up the governor
  11. Re-assembled everything and refilled - again
  12. Test drive 28th March - still no third gear
  13. Ever hopeful, tried again 31st March, and discovered that by selecting 2 with the gear change and then selecting D, hey presto a 2-3 change occurred.
  14. Tried this several times, and after several successful manually induced 2-3 changes, discovered that the car would now do the 2-3 changes without manual interference.
A big big thank you to Andy for all his help with this, and also to Harvey for diagnostics and pointing me in the right direction to get help. It was a bit of a mission, but we got there in the end. Next time I have a few moments free I'll post some pictures.
 
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