ProteuS Posted August 31, 2014 Share Posted August 31, 2014 I've recently bought a a 4.6 p38 - (really as a future engine donor for my RRC project) but have become quite attached to it. It drove ok when I purchased it although was sometimes a little funny on kickdowns. Then one day on coming onto a slip road and flooring it I ended up with next to no drive. I've trailered it home and it seems to select all gears and in low ratio will drive reverse and forwards a small amount but application of throttle doesn't result in any appreciable speed increase. I've checked the fluid levels cold, with the engine running and they're good. The oil is also red and doesn't smell burned. I intend to change the filter just in case. Does anyone have any probable candidates? It feels like a slipping clutch in a manual so I wondered if both clutch packs had had it, or possible a torque converter issue. Quote Link to comment Share on other sites More sharing options...
dave88sw Posted August 31, 2014 Share Posted August 31, 2014 dont want to teach you to suck eggs or anything but have you been checking the level with the engine running and the box in neutral? Is there any noise with the lack of drive (once had a p38 strip the splines of its viscous coupling in the transfer box, it would move off but if you gunned it, it would just grate and go nowhere)? Quote Link to comment Share on other sites More sharing options...
pete3000 Posted August 31, 2014 Share Posted August 31, 2014 Does it work better manually going up the gears i.e start off in 1,2,3 instead of D? The sprag clutch can go as described on Ashcroft transmission pages http://www.ashcroft-transmissions.co.uk/automatic-gearboxes/zf4hp22.html at the bottom of the page. P38 we have wouldn't do reverse well until it had warmed up, and hesitated on change up's from cold in D, which is another common fault where a filter gets blocked up in the internals (not the one in the sump). Quote Link to comment Share on other sites More sharing options...
ProteuS Posted August 31, 2014 Author Share Posted August 31, 2014 dont want to teach you to suck eggs or anything but have you been checking the level with the engine running and the box in neutral? Is there any noise with the lack of drive (once had a p38 strip the splines of its viscous coupling in the transfer box, it would move off but if you gunned it, it would just grate and go nowhere)? Yeah, cold engine and box, running in neutral, then cycling through all gears and back to neutral. Oil level comes to top dot of the two. There's no noise that I can discern and certainly nothing that gets louder other than the engine on rpm increase. Does it work better manually going up the gears i.e start off in 1,2,3 instead of D? The sprag clutch can go as described on Ashcroft transmission pages http://www.ashcroft-transmissions.co.uk/automatic-gearboxes/zf4hp22.html at the bottom of the page. P38 we have wouldn't do reverse well until it had warmed up, and hesitated on change up's from cold in D, which is another common fault where a filter gets blocked up in the internals (not the one in the sump). Very interesting, no going manually through the gears doesn't help at all. The lowest gear gives some hint of movement but not much at all. (same for D) an incline is about enough to stop its forward motion. I've only had it a couple of times where with a bit of oscillating throttle and it seems to grab and give more drive. Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 1, 2014 Share Posted September 1, 2014 Sounds more like the torque converter to me? How sure are you about the engine's performance? Was it running well? I've had before (with the fuel trims massively out of whack) that I could only move it in low box, and even then very slowly, purely due to the engine running badly. But that was accompanied by a lot of plopping in the exhaust and such, so you would've noticed. Quote Link to comment Share on other sites More sharing options...
ProteuS Posted September 1, 2014 Author Share Posted September 1, 2014 Sounds more like the torque converter to me? How sure are you about the engine's performance? Was it running well? I've had before (with the fuel trims massively out of whack) that I could only move it in low box, and even then very slowly, purely due to the engine running badly. But that was accompanied by a lot of plopping in the exhaust and such, so you would've noticed. I did wonder about the TC . I'm fairly certain about the engines performance. It had been running well and performance was good. It runs smoothly and doens't seem to be struggling Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 1, 2014 Share Posted September 1, 2014 I've heard they can slip transfer box chains, but that's accompanied by a noise! Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 1, 2014 Share Posted September 1, 2014 Yeah, sounds like a machine gun going off. Quote Link to comment Share on other sites More sharing options...
ProteuS Posted September 1, 2014 Author Share Posted September 1, 2014 Yeah, definitely none of that. No unusual sounds and certainly nothing grinding. I'm wondering if it is the filter that is blocked and not allowing enough fluid flow. Although the fluid is pretty clean. I've a new filter on order and will try it just in case. Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 2, 2014 Share Posted September 2, 2014 Definitely worth a try. Is it a Bosch or a GEMS? Quote Link to comment Share on other sites More sharing options...
ProteuS Posted September 2, 2014 Author Share Posted September 2, 2014 It's a GEMS - 1995 Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 2, 2014 Share Posted September 2, 2014 Hmm, don't really know about that one. I know with the Bosch gearbox you can look at which valves are actuated etc via the diagnostics. Not sure how much help that'd be though. Quote Link to comment Share on other sites More sharing options...
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